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Microsoft SharePoint

product · product:microsoft-sharepoint single-sourcesingle-source-victim

Also known as: SharePoint, SharePoint Server

Coverage
10
first 2026-07-02 → last 2026-10-03
Latest activity
2026-10-03
Symantec: Warlock's operator steals SharePoint machine keys, forges signed payloads and ships ransomware via…
Peak priority
high
7 high · 3 notable
Targets
public-sector
sectors: public-sector, healthcare, technology · regions: europe, switzerland, africa
Sources cited
47
28 hosts

Action items (14)

Do-now tasks recorded on the entries about Microsoft SharePoint, newest first. Check the date before acting on an older one.

  • On every on-premises SharePoint Server farm that was reachable from the internet while unpatched, patch it and then rotate the ASP.NET machine keys and restart IIS on all SharePoint servers, as Microsoft's ToolShell guidance says, and look for unexpected .aspx files in the LAYOUTS template directories of every installed SharePoint version and for domain accounts named like SharePoint setup accounts in local Administrators groups.
    2026-10-03Symantec: Warlock's operator steals SharePoint…
  • Patch every Microsoft SharePoint Enterprise Server 2016, Server 2019 and Subscription Edition instance to the 11 August 2026 cumulative update (or later) now, and confirm the separate 9 June 2026 ToolPane-authentication-bypass patch is also applied; its absence is what turns this bug into a pre-authentication chain on servers configured for anonymous access.
    2026-09-26CVE-2026-65660
  • Confirm every on-premises SharePoint farm is at or above the August 2026 build for its line, and every on-prem AD FS server carries the July 2026 cumulative update: CVE-2026-56155, CVE-2026-56164, CVE-2026-55040 and CVE-2026-58644 are all confirmed exploited and KEV-listed. For any farm that was internet-reachable while unpatched, run a compromise assessment for forged-token access rather than closing the ticket on the upgrade.
    2026-07-14CVE-2026-56155 +6
  • Before rotating IIS machine keys on any SharePoint that was internet-reachable, hunt for and evict machine-key harvesters first; CISA warns that rotating keys ahead of eviction lets a resident implant re-harvest the new keys.
    2026-07-14CVE-2026-56155 +6
  • On every internet-reachable on-premises SharePoint farm, search the server-side trace logs back to 2026-08-11 for the issuer-validation message that records an issuer being accepted because no registered token service matched the signing certificate; it fires on the decisive step of this bypass and is the one artefact that separates a forged token from a normal one.
    2026-07-14CVE-2026-56155 +6
9 older action items
  • Apply the May SharePoint update now if you deferred it; CVE-2026-45659 is now KEV-listed as actively exploited despite Microsoft's "Exploitation Less Likely" rating; the fix has shipped since 21 May. Hunt SharePoint/IIS logs for anomalous POST bodies to object-model/API endpoints from Site-Member sessions followed by unexpected w3wp.exe child processes.
    2026-07-02CVE-2026-45659
  • Search every on-premises SharePoint farm in cantonal and communal estates for files created under the web-application or layouts directories between 20 July and 5 August 2026, regardless of current patch level, Graubünden found two planted files on a farm where no account compromise and no data loss were detected, so a clean identity picture does not rule the farm out.
    2026-08-06A second Swiss public-sector SharePoint victim in…
  • Rotate the ASP.NET machine keys on every on-premises SharePoint farm that was internet-reachable during the July exploitation window, and do it after evicting any resident web shell rather than before, a harvester still on the box simply re-reads the new keys.
    2026-08-05Swiss federal SharePoint servers breached…
  • Re-authenticate and reset every service and technical account that holds credentials on an exposed SharePoint farm; these are the accounts least likely to be covered by interactive-logon MFA and the ~200 taken at BIT were user and technical accounts alike.
    2026-08-05Swiss federal SharePoint servers breached…
  • Cross-check your asset inventory for MeshCentral MeshAgent and Zoho Assist Unattended Agent instances that your own management platform did not provision, treating any such agent running as a SYSTEM auto-start service as an incident rather than a hygiene finding; both were the primary command-and-control mechanism in the ransomware engagements Talos describes.
    2026-07-29Cisco Talos IR's quarterly report puts three named…
  • Raise domain-controller security-log retention and forward it off-device: Talos found DC logs retained for only a few hours, and states the resulting gaps prevented determining the initial access vector or exfiltration scope in real engagements; 90 days of centralised retention is the figure it names.
    2026-07-29Cisco Talos IR's quarterly report puts three named…
  • Block or tightly scope the Entra ID device-code authentication flow tenant-wide, ReliaQuest names this the single highest-impact control, because it neutralises the session-token capture regardless of how convincing the vishing pretext is.
    2026-07-10ReliaQuest: new 'Helix' extortion cluster…
  • Alert on a new MFA-authenticator registration occurring within minutes of a device-code sign-in from a residential-proxy IP the account has never used, that co-occurrence is Helix's persistence artifact and is otherwise indistinguishable from normal user activity.
    2026-07-10ReliaQuest: new 'Helix' extortion cluster…
  • Hunt SharePoint/Graph access logs for enumeration using contentclass:STS_Site and wildcard search queries at automation speed from a non-browser (python-requests) user-agent, followed by bulk downloads; the automated-collection stage is the most reliable fingerprint.
    2026-07-10ReliaQuest: new 'Helix' extortion cluster…

Defender insights

What each entry about Microsoft SharePoint tells a defender to do, newest first.

2026-10-03HIGHSymantec: Warlock's operator steals SharePoint machine keys, forges signed payloads and ships ransomware via SYSVOL

Exposure · triage · detection

2026-09-26HIGHexploitedMicrosoft confirms active exploitation of a SharePoint bug it quietly re-rated a month earlier

Triage

2026-09-07NOTABLEInsikt Group: the same six-tool stack followed thirteen unrelated CVEs into Exchange, SharePoint, FortiOS, Cisco IOS XE, F5 BIG-IP, GeoServer and Apache Shiro

2026-07-14HIGHexploitedMicrosoft patches two exploited zero-days on-prem: an AD FS privilege escalation and an unauthenticated SharePoint EoP, both KEV-listed same day

Latest update · triage

2026-07-02HIGHexploitedCVE-2026-45659, Microsoft SharePoint Server: authenticated deserialization RCE, now KEV-listed

2026-08-06HIGHexploitedA second Swiss public-sector SharePoint victim in 48 hours, and the intrusion sat unnoticed for a week

Triage

4 earlier entries carry guidance too, listed under the story timeline below.

Story timeline

  1. 2026-10-03Longlegs (Storm-2603), the developer of Warlock ransomware, still enters through on-premises SharePoint: a water utility, a telecom, a regional government body and a university hit in two months
    active-threatsSymantec: Warlock's operator steals SharePoint machine keys, forges signed payloads and ships ransomware via SYSVOL
  2. 2026-09-26CVE-2026-65660, Microsoft SharePoint: a SafeControls parser-desync lets an authenticated attacker forge a second Register directive and reach RCE via in-memory XAML deserialization, now confirmed exploited (CVSS 8.8)
    trending-vulnerabilitiesMicrosoft confirms active exploitation of a SharePoint bug it quietly re-rated a month earlier
  3. 2026-09-07Recorded Future's H1 2026 Malware and Vulnerability Trends: two clusters reuse an identical post-exploitation tool stack across thirteen and ten unrelated initial CVEs
    researchInsikt Group: the same six-tool stack followed thirteen unrelated CVEs into Exchange, SharePoint, FortiOS, Cisco IOS XE, F5 BIG-IP, GeoServer and Apache Shiro
  4. 2026-08-06Canton Graubünden discloses a SharePoint server breach a day after the Confederation did; the on-premises wave has reached Swiss cantonal government
    active-threatsA second Swiss public-sector SharePoint victim in 48 hours, and the intrusion sat unnoticed for a week
  5. 2026-08-05Switzerland's federal IT provider BIT confirms a SharePoint Server intrusion: ~200 federal user and technical accounts compromised while the July patches were already being installed
    deep-diveSwiss federal SharePoint servers breached mid-patching, ~200 accounts taken, servers now being rebuilt
  6. 2026-07-29Talos IR Trends Q2 2026: ransomware operators ran their command-and-control through legitimate RMM agents, authentication abuse hit two-thirds of engagements, and missing logs stopped root-cause determination outright
    deep-diveCisco Talos IR's quarterly report puts three named intrusion chains on record, led by Sinobi running its command-and-control through a trojanized MeshAgent
  7. 2026-07-18Abbott confirms a Cancer Diagnostics cyber incident; ShinyHunters claims a vished Entra SSO account and 30M+ records
    active-threatsAbbott confirms unauthorized access to its Cancer Diagnostics (Exact Sciences) systems as ShinyHunters claims a helpdesk-vishing to Entra SSO breach
  8. 2026-07-14Microsoft July 2026 Patch Tuesday ships two actively-exploited zero-days, AD FS local EoP (CVE-2026-56155) and unauthenticated SharePoint EoP (CVE-2026-56164)
    trending-vulnerabilitiesMicrosoft patches two exploited zero-days on-prem: an AD FS privilege escalation and an unauthenticated SharePoint EoP, both KEV-listed same day
  9. 2026-07-10'Helix' data-extortion cluster pairs manager-impersonation vishing with device-code phishing and automated SharePoint exfiltration
    active-threatsReliaQuest: new 'Helix' extortion cluster (BlackFile/ShinyHunters lineage) vishes staff into device-code sign-ins, then bulk-loots SharePoint
  10. 2026-07-02CVE-2026-45659, Microsoft SharePoint Server: authenticated deserialization RCE, now KEV-listed
    trending-vulnerabilities

Hunting pivots

Releases covered
Microsoft SharePoint ×4Microsoft SharePoint Enterprise Server 2016 ×3Microsoft SharePoint Server ×3Microsoft SharePoint Server 2019 ×3Microsoft SharePoint Server Subscription Edition ×3Microsoft SharePoint Server 2016
ATT&CK techniques (50 across 14 tactics)

50 techniques observed across 10 entries about this entity, derived from entry metadata and body evidence, never asserted without a published entry behind it · pinned to MITRE ATT&CK v20.0 · compare on the matrix · Navigator layer (JSON)

  • ReconnaissancePhishing for Information · Phishing for Information: Spearphishing Voice
  • Initial AccessValid Accounts · Valid Accounts: Cloud Accounts · Exploit Public-Facing Application · Phishing: Spearphishing Attachment · Phishing: Spearphishing Voice
  • ExecutionCommand and Scripting Interpreter: PowerShell · Command and Scripting Interpreter: Windows Command Shell · Command and Scripting Interpreter: Unix Shell · Hijack Execution Flow: DLL
  • PersistenceValid Accounts · Valid Accounts: Cloud Accounts · Account Manipulation · Account Manipulation: Device Registration · Server Software Component: Web Shell · Create or Modify System Process: Windows Service · Modify Authentication Process: Multi-Factor Authentication
  • Privilege EscalationExploitation for Privilege Escalation · Valid Accounts · Valid Accounts: Cloud Accounts · Account Manipulation · Account Manipulation: Device Registration · Domain or Tenant Policy Modification: Group Policy Modification · Create or Modify System Process: Windows Service
  • StealthMasquerading: Masquerade Account Name · Valid Accounts · Valid Accounts: Cloud Accounts · Exploitation for Stealth · System Binary Proxy Execution: Msiexec · Hide Artifacts: Email Hiding Rules · Hijack Execution Flow: DLL
  • Defense ImpairmentDomain or Tenant Policy Modification: Group Policy Modification · Modify Authentication Process: Multi-Factor Authentication · Disable or Modify Tools
  • Credential AccessOS Credential Dumping: NTDS · Brute Force: Password Spraying · Multi-Factor Authentication Interception · Steal Application Access Token · Unsecured Credentials: Private Keys · Modify Authentication Process: Multi-Factor Authentication · Adversary-in-the-Middle · Forge Web Credentials · Multi-Factor Authentication Request Generation
  • DiscoverySystem Information Discovery · Account Discovery: Domain Account · Domain Trust Discovery
  • Lateral MovementRemote Services: Remote Desktop Protocol · Remote Services: Windows Remote Management · Internal Spearphishing · Use Alternate Authentication Material: Application Access Token · Lateral Tool Transfer
  • CollectionData from Local System · Data from Information Repositories: Sharepoint · Data from Cloud Storage · Adversary-in-the-Middle
  • Command and ControlApplication Layer Protocol: Web Protocols · Web Service · Ingress Tool Transfer · Remote Access Tools · Remote Access Tools: IDE Tunneling
  • ExfiltrationExfiltration Over C2 Channel · Exfiltration Over Web Service
  • ImpactData Encrypted for Impact

Reconnaissance TA0043

T1598Phishing for Information×1

Adversaries may send phishing messages to elicit sensitive information that can be used during targeting. Phishing for information is an attempt to trick targets into divulging information, frequently credentials or other actionable information. Phishing for information is different from Phishing in that the objective is gathering data from the victim rather than executing malicious code.

Evidence: 2026-07-29/talos-ir-trends-q2-2026-rmm-weaponization-auth-abuse · ATT&CK page ↗

T1598.004Phishing for Information: Spearphishing Voice×1

Adversaries may use voice communications to elicit sensitive information that can be used during targeting. Spearphishing for information is an attempt to trick targets into divulging information, frequently credentials or other actionable information. Spearphishing for information frequently involves social engineering techniques, such as posing as a source with a reason to collect information (ex: Impersonation) and/or creating a sense of urgency or alarm for the recipient.

Evidence: 2026-07-18/abbott-exact-sciences-shinyhunters-entra-sso-vishing · ATT&CK page ↗

Initial Access TA0001

T1078Valid Accounts×3

Adversaries may obtain and abuse credentials of existing accounts as a means of gaining Initial Access, Persistence, Privilege Escalation, or Defense Evasion. Compromised credentials may be used to bypass access controls placed on various resources on systems within the network and may even be used for persistent access to remote systems and externally available services, such as VPNs, Outlook Web Access, network devices, and remote desktop. Compromised credentials may also grant an adversary increased privilege to specific systems or access to restricted areas of the network. Adversaries may choose not to use malware or tools in conjunction with the legitimate access those credentials provide to make it harder to detect their presence.

Evidence: 2026-08-05/bit-foitt-swiss-federal-sharepoint-breach-200-accounts · 2026-07-29/talos-ir-trends-q2-2026-rmm-weaponization-auth-abuse · 2026-07-14/microsoft-july-2026-patch-tuesday-two-exploited-zero-days · ATT&CK page ↗

T1078.004Valid Accounts: Cloud Accounts×1

Valid accounts in cloud environments may allow adversaries to perform actions to achieve Initial Access, Persistence, Privilege Escalation, or Defense Evasion. Cloud accounts are those created and configured by an organization for use by users, remote support, services, or for administration of resources within a cloud service provider or SaaS application. Cloud Accounts can exist solely in the cloud; alternatively, they may be hybrid-joined between on-premises systems and the cloud through syncing or federation with other identity sources such as Windows Active Directory.

Evidence: 2026-07-18/abbott-exact-sciences-shinyhunters-entra-sso-vishing · ATT&CK page ↗

T1190Exploit Public-Facing Application×8
T1566.001Phishing: Spearphishing Attachment×1

Adversaries may send spearphishing emails with a malicious attachment in an attempt to gain access to victim systems. Spearphishing attachment is a specific variant of spearphishing. Spearphishing attachment is different from other forms of spearphishing in that it employs the use of malware attached to an email. All forms of spearphishing are electronically delivered social engineering targeted at a specific individual, company, or industry. In this scenario, adversaries attach a file to the spearphishing email and usually rely upon User Execution to gain execution. Spearphishing may also involve social engineering techniques, such as posing as a trusted source.

Evidence: 2026-07-29/talos-ir-trends-q2-2026-rmm-weaponization-auth-abuse · ATT&CK page ↗

T1566.004Phishing: Spearphishing Voice×2

Adversaries may use voice communications to ultimately gain access to victim systems. Spearphishing voice is a specific variant of spearphishing. It is different from other forms of spearphishing in that it employs the use of manipulating a user into providing access to systems through a phone call or other forms of voice communications. Spearphishing frequently involves social engineering techniques, such as posing as a trusted source (ex: Impersonation) and/or creating a sense of urgency or alarm for the recipient.

Evidence: 2026-07-18/abbott-exact-sciences-shinyhunters-entra-sso-vishing · 2026-07-10/helix-data-extortion-devicecode-vishing-sharepoint-exfil · ATT&CK page ↗

Execution TA0002

T1059.001Command and Scripting Interpreter: PowerShell×2

Adversaries may abuse PowerShell commands and scripts for execution. PowerShell is a powerful interactive command-line interface and scripting environment included in the Windows operating system. PowerShell can also be installed on Linux and macOS. Adversaries can use PowerShell to perform a number of actions, including discovery of information and execution of code. Examples include the <code>Start-Process</code> cmdlet which can be used to run an executable and the <code>Invoke-Command</code> cmdlet which runs a command locally or on a remote computer (though administrator permissions are required to use PowerShell to connect to remote systems).

Evidence: 2026-10-03/warlock-longlegs-sharepoint-machinekey-sysvol-ransomware · 2026-09-07/recordedfuture-h1-2026-tool-stack-reuse · ATT&CK page ↗

T1059.003Command and Scripting Interpreter: Windows Command Shell×2

Adversaries may abuse the Windows command shell for execution. The Windows command shell (cmd) is the primary command prompt on Windows systems. The Windows command prompt can be used to control almost any aspect of a system, with various permission levels required for different subsets of commands. The command prompt can be invoked remotely via Remote Services such as SSH.

Evidence: 2026-10-03/warlock-longlegs-sharepoint-machinekey-sysvol-ransomware · 2026-09-07/recordedfuture-h1-2026-tool-stack-reuse · ATT&CK page ↗

T1059.004Command and Scripting Interpreter: Unix Shell×1

Adversaries may abuse Unix shell commands and scripts for execution. Unix shells are the primary command prompt on Linux, macOS, and ESXi systems, though many variations of the Unix shell exist (e.g. sh, ash, bash, zsh, etc.) depending on the specific OS or distribution. Unix shells can control every aspect of a system, with certain commands requiring elevated privileges.

Evidence: 2026-09-07/recordedfuture-h1-2026-tool-stack-reuse · ATT&CK page ↗

T1574.001Hijack Execution Flow: DLL×1

Adversaries may abuse dynamic-link library files (DLLs) in order to achieve persistence, escalate privileges, and evade defenses. DLLs are libraries that contain code and data that can be simultaneously utilized by multiple programs. While DLLs are not malicious by nature, they can be abused through mechanisms such as side-loading, hijacking search order, and phantom DLL hijacking.

Evidence: 2026-10-03/warlock-longlegs-sharepoint-machinekey-sysvol-ransomware · ATT&CK page ↗

Persistence TA0003

T1078Valid Accounts×3

Adversaries may obtain and abuse credentials of existing accounts as a means of gaining Initial Access, Persistence, Privilege Escalation, or Defense Evasion. Compromised credentials may be used to bypass access controls placed on various resources on systems within the network and may even be used for persistent access to remote systems and externally available services, such as VPNs, Outlook Web Access, network devices, and remote desktop. Compromised credentials may also grant an adversary increased privilege to specific systems or access to restricted areas of the network. Adversaries may choose not to use malware or tools in conjunction with the legitimate access those credentials provide to make it harder to detect their presence.

Evidence: 2026-08-05/bit-foitt-swiss-federal-sharepoint-breach-200-accounts · 2026-07-29/talos-ir-trends-q2-2026-rmm-weaponization-auth-abuse · 2026-07-14/microsoft-july-2026-patch-tuesday-two-exploited-zero-days · ATT&CK page ↗

T1078.004Valid Accounts: Cloud Accounts×1

Valid accounts in cloud environments may allow adversaries to perform actions to achieve Initial Access, Persistence, Privilege Escalation, or Defense Evasion. Cloud accounts are those created and configured by an organization for use by users, remote support, services, or for administration of resources within a cloud service provider or SaaS application. Cloud Accounts can exist solely in the cloud; alternatively, they may be hybrid-joined between on-premises systems and the cloud through syncing or federation with other identity sources such as Windows Active Directory.

Evidence: 2026-07-18/abbott-exact-sciences-shinyhunters-entra-sso-vishing · ATT&CK page ↗

T1098Account Manipulation×1

Adversaries may manipulate accounts to maintain and/or elevate access to victim systems. Account manipulation may consist of any action that preserves or modifies adversary access to a compromised account, such as modifying credentials or permission groups. These actions could also include account activity designed to subvert security policies, such as performing iterative password updates to bypass password duration policies and preserve the life of compromised credentials.

Evidence: 2026-10-03/warlock-longlegs-sharepoint-machinekey-sysvol-ransomware · ATT&CK page ↗

T1098.005Account Manipulation: Device Registration×2

Adversaries may register a device to an adversary-controlled account. Devices may be registered in a multifactor authentication (MFA) system, which handles authentication to the network, or in a device management system, which handles device access and compliance.

Evidence: 2026-07-29/talos-ir-trends-q2-2026-rmm-weaponization-auth-abuse · 2026-07-10/helix-data-extortion-devicecode-vishing-sharepoint-exfil · ATT&CK page ↗

T1505.003Server Software Component: Web Shell×5

Adversaries may backdoor web servers with web shells to establish persistent access to systems. A Web shell is a Web script that is placed on an openly accessible Web server to allow an adversary to access the Web server as a gateway into a network. A Web shell may provide a set of functions to execute or a command-line interface on the system that hosts the Web server.

Evidence: 2026-10-03/warlock-longlegs-sharepoint-machinekey-sysvol-ransomware · 2026-09-26/cve-2026-65660-microsoft-sharepoint-safecontrols-bypass-rce · 2026-09-07/recordedfuture-h1-2026-tool-stack-reuse · 2026-07-14/microsoft-july-2026-patch-tuesday-two-exploited-zero-days · 2026-07-02/cve-2026-45659-microsoft-sharepoint-server-authenticated-des · ATT&CK page ↗

T1543.003Create or Modify System Process: Windows Service×1

Adversaries may create or modify Windows services to repeatedly execute malicious payloads as part of persistence. When Windows boots up, it starts programs or applications called services that perform background system functions. Windows service configuration information, including the file path to the service's executable or recovery programs/commands, is stored in the Windows Registry.

Evidence: 2026-07-29/talos-ir-trends-q2-2026-rmm-weaponization-auth-abuse · ATT&CK page ↗

T1556.006Modify Authentication Process: Multi-Factor Authentication×1

Adversaries may disable or modify multi-factor authentication (MFA) mechanisms to enable persistent access to compromised accounts.

Evidence: 2026-07-18/abbott-exact-sciences-shinyhunters-entra-sso-vishing · ATT&CK page ↗

Privilege Escalation TA0004

T1068Exploitation for Privilege Escalation×1

Adversaries may exploit software vulnerabilities in an attempt to elevate privileges. Exploitation of a software vulnerability occurs when an adversary takes advantage of a programming error in a program, service, or within the operating system software or kernel itself to execute adversary-controlled code. Security constructs such as permission levels will often hinder access to information and use of certain techniques, so adversaries will likely need to perform privilege escalation to include use of software exploitation to circumvent those restrictions.

Evidence: 2026-07-14/microsoft-july-2026-patch-tuesday-two-exploited-zero-days · ATT&CK page ↗

T1078Valid Accounts×3

Adversaries may obtain and abuse credentials of existing accounts as a means of gaining Initial Access, Persistence, Privilege Escalation, or Defense Evasion. Compromised credentials may be used to bypass access controls placed on various resources on systems within the network and may even be used for persistent access to remote systems and externally available services, such as VPNs, Outlook Web Access, network devices, and remote desktop. Compromised credentials may also grant an adversary increased privilege to specific systems or access to restricted areas of the network. Adversaries may choose not to use malware or tools in conjunction with the legitimate access those credentials provide to make it harder to detect their presence.

Evidence: 2026-08-05/bit-foitt-swiss-federal-sharepoint-breach-200-accounts · 2026-07-29/talos-ir-trends-q2-2026-rmm-weaponization-auth-abuse · 2026-07-14/microsoft-july-2026-patch-tuesday-two-exploited-zero-days · ATT&CK page ↗

T1078.004Valid Accounts: Cloud Accounts×1

Valid accounts in cloud environments may allow adversaries to perform actions to achieve Initial Access, Persistence, Privilege Escalation, or Defense Evasion. Cloud accounts are those created and configured by an organization for use by users, remote support, services, or for administration of resources within a cloud service provider or SaaS application. Cloud Accounts can exist solely in the cloud; alternatively, they may be hybrid-joined between on-premises systems and the cloud through syncing or federation with other identity sources such as Windows Active Directory.

Evidence: 2026-07-18/abbott-exact-sciences-shinyhunters-entra-sso-vishing · ATT&CK page ↗

T1098Account Manipulation×1

Adversaries may manipulate accounts to maintain and/or elevate access to victim systems. Account manipulation may consist of any action that preserves or modifies adversary access to a compromised account, such as modifying credentials or permission groups. These actions could also include account activity designed to subvert security policies, such as performing iterative password updates to bypass password duration policies and preserve the life of compromised credentials.

Evidence: 2026-10-03/warlock-longlegs-sharepoint-machinekey-sysvol-ransomware · ATT&CK page ↗

T1098.005Account Manipulation: Device Registration×2

Adversaries may register a device to an adversary-controlled account. Devices may be registered in a multifactor authentication (MFA) system, which handles authentication to the network, or in a device management system, which handles device access and compliance.

Evidence: 2026-07-29/talos-ir-trends-q2-2026-rmm-weaponization-auth-abuse · 2026-07-10/helix-data-extortion-devicecode-vishing-sharepoint-exfil · ATT&CK page ↗

T1484.001Domain or Tenant Policy Modification: Group Policy Modification×1

Adversaries may modify Group Policy Objects (GPOs) to subvert the intended discretionary access controls for a domain, usually with the intention of escalating privileges on the domain. Group policy allows for centralized management of user and computer settings in Active Directory (AD). GPOs are containers for group policy settings made up of files stored within a predictable network path `\<DOMAIN>\SYSVOL\<DOMAIN>\Policies\`.

Evidence: 2026-07-29/talos-ir-trends-q2-2026-rmm-weaponization-auth-abuse · ATT&CK page ↗

T1543.003Create or Modify System Process: Windows Service×1

Adversaries may create or modify Windows services to repeatedly execute malicious payloads as part of persistence. When Windows boots up, it starts programs or applications called services that perform background system functions. Windows service configuration information, including the file path to the service's executable or recovery programs/commands, is stored in the Windows Registry.

Evidence: 2026-07-29/talos-ir-trends-q2-2026-rmm-weaponization-auth-abuse · ATT&CK page ↗

Stealth TA0005

T1036.010Masquerading: Masquerade Account Name×1

Adversaries may match or approximate the names of legitimate accounts to make newly created ones appear benign. This will typically occur during Create Account, although accounts may also be renamed at a later date. This may also coincide with Account Access Removal if the actor first deletes an account before re-creating one with the same name.

Evidence: 2026-10-03/warlock-longlegs-sharepoint-machinekey-sysvol-ransomware · ATT&CK page ↗

T1078Valid Accounts×3

Adversaries may obtain and abuse credentials of existing accounts as a means of gaining Initial Access, Persistence, Privilege Escalation, or Defense Evasion. Compromised credentials may be used to bypass access controls placed on various resources on systems within the network and may even be used for persistent access to remote systems and externally available services, such as VPNs, Outlook Web Access, network devices, and remote desktop. Compromised credentials may also grant an adversary increased privilege to specific systems or access to restricted areas of the network. Adversaries may choose not to use malware or tools in conjunction with the legitimate access those credentials provide to make it harder to detect their presence.

Evidence: 2026-08-05/bit-foitt-swiss-federal-sharepoint-breach-200-accounts · 2026-07-29/talos-ir-trends-q2-2026-rmm-weaponization-auth-abuse · 2026-07-14/microsoft-july-2026-patch-tuesday-two-exploited-zero-days · ATT&CK page ↗

T1078.004Valid Accounts: Cloud Accounts×1

Valid accounts in cloud environments may allow adversaries to perform actions to achieve Initial Access, Persistence, Privilege Escalation, or Defense Evasion. Cloud accounts are those created and configured by an organization for use by users, remote support, services, or for administration of resources within a cloud service provider or SaaS application. Cloud Accounts can exist solely in the cloud; alternatively, they may be hybrid-joined between on-premises systems and the cloud through syncing or federation with other identity sources such as Windows Active Directory.

Evidence: 2026-07-18/abbott-exact-sciences-shinyhunters-entra-sso-vishing · ATT&CK page ↗

T1211Exploitation for Stealth×1

Adversaries may exploit vulnerabilities to evade detection by hiding activity, suppressing logging, or operating within trusted or unmonitored components.

Evidence: 2026-07-14/microsoft-july-2026-patch-tuesday-two-exploited-zero-days · ATT&CK page ↗

T1218.007System Binary Proxy Execution: Msiexec×1

Adversaries may abuse msiexec.exe to proxy execution of malicious payloads. Msiexec.exe is the command-line utility for the Windows Installer and is thus commonly associated with executing installation packages (.msi). The Msiexec.exe binary may also be digitally signed by Microsoft.

Evidence: 2026-10-03/warlock-longlegs-sharepoint-machinekey-sysvol-ransomware · ATT&CK page ↗

T1564.008Hide Artifacts: Email Hiding Rules×1

Adversaries may use email rules to hide inbound emails in a compromised user's mailbox. Many email clients allow users to create inbox rules for various email functions, including moving emails to other folders, marking emails as read, or deleting emails. Rules may be created or modified within email clients or through external features such as the <code>New-InboxRule</code> or <code>Set-InboxRule</code> PowerShell cmdlets on Windows systems.

Evidence: 2026-07-29/talos-ir-trends-q2-2026-rmm-weaponization-auth-abuse · ATT&CK page ↗

T1574.001Hijack Execution Flow: DLL×1

Adversaries may abuse dynamic-link library files (DLLs) in order to achieve persistence, escalate privileges, and evade defenses. DLLs are libraries that contain code and data that can be simultaneously utilized by multiple programs. While DLLs are not malicious by nature, they can be abused through mechanisms such as side-loading, hijacking search order, and phantom DLL hijacking.

Evidence: 2026-10-03/warlock-longlegs-sharepoint-machinekey-sysvol-ransomware · ATT&CK page ↗

Defense Impairment TA0112

T1484.001Domain or Tenant Policy Modification: Group Policy Modification×1

Adversaries may modify Group Policy Objects (GPOs) to subvert the intended discretionary access controls for a domain, usually with the intention of escalating privileges on the domain. Group policy allows for centralized management of user and computer settings in Active Directory (AD). GPOs are containers for group policy settings made up of files stored within a predictable network path `\<DOMAIN>\SYSVOL\<DOMAIN>\Policies\`.

Evidence: 2026-07-29/talos-ir-trends-q2-2026-rmm-weaponization-auth-abuse · ATT&CK page ↗

T1556.006Modify Authentication Process: Multi-Factor Authentication×1

Adversaries may disable or modify multi-factor authentication (MFA) mechanisms to enable persistent access to compromised accounts.

Evidence: 2026-07-18/abbott-exact-sciences-shinyhunters-entra-sso-vishing · ATT&CK page ↗

T1685Disable or Modify Tools×1

Adversaries may disable, degrade, or tamper with security tools or applications (e.g., endpoint detection and response (EDR) tools, intrusion detection systems (IDS), antivirus, logging agents, sensors, etc.) to impair or reduce visibility of defensive capabilities. This may include stopping specific services, killing processes, modifying or deleting tool configuration files and Registry keys, or preventing tools from updating. This may also include impairing defenses more broadly by disrupting preventative, detection, and response mechanisms across host, network, and cloud environments.

Evidence: 2026-10-03/warlock-longlegs-sharepoint-machinekey-sysvol-ransomware · ATT&CK page ↗

Credential Access TA0006

T1003.003OS Credential Dumping: NTDS×1

Adversaries may attempt to access or create a copy of the Active Directory domain database in order to steal credential information, as well as obtain other information about domain members such as devices, users, and access rights. By default, the NTDS file (NTDS.dit) is located in <code>%SystemRoot%\NTDS\Ntds.dit</code> of a domain controller.

Evidence: 2026-07-29/talos-ir-trends-q2-2026-rmm-weaponization-auth-abuse · ATT&CK page ↗

T1110.003Brute Force: Password Spraying×1

Adversaries may use a single or small list of commonly used passwords against many different accounts to attempt to acquire valid account credentials. Password spraying uses one password (e.g. 'Password01'), or a small list of commonly used passwords, that may match the complexity policy of the domain. Logins are attempted with that password against many different accounts on a network to avoid account lockouts that would normally occur when brute forcing a single account with many passwords.

Evidence: 2026-10-03/warlock-longlegs-sharepoint-machinekey-sysvol-ransomware · ATT&CK page ↗

T1111Multi-Factor Authentication Interception×1

Adversaries may target multi-factor authentication (MFA) mechanisms, (i.e., smart cards, token generators, etc.) to gain access to credentials that can be used to access systems, services, and network resources. Use of MFA is recommended and provides a higher level of security than usernames and passwords alone, but organizations should be aware of techniques that could be used to intercept and bypass these security mechanisms.

Evidence: 2026-07-29/talos-ir-trends-q2-2026-rmm-weaponization-auth-abuse · ATT&CK page ↗

T1528Steal Application Access Token×1

Adversaries can steal application access tokens as a means of acquiring credentials to access remote systems and resources.

Evidence: 2026-07-10/helix-data-extortion-devicecode-vishing-sharepoint-exfil · ATT&CK page ↗

T1552.004Unsecured Credentials: Private Keys×1

Adversaries may search for private key certificate files on compromised systems for insecurely stored credentials. Private cryptographic keys and certificates are used for authentication, encryption/decryption, and digital signatures. Common key and certificate file extensions include: .key, .pgp, .gpg, .ppk., .p12, .pem, .pfx, .cer, .p7b, .asc.

Evidence: 2026-07-14/microsoft-july-2026-patch-tuesday-two-exploited-zero-days · ATT&CK page ↗

T1556.006Modify Authentication Process: Multi-Factor Authentication×1

Adversaries may disable or modify multi-factor authentication (MFA) mechanisms to enable persistent access to compromised accounts.

Evidence: 2026-07-18/abbott-exact-sciences-shinyhunters-entra-sso-vishing · ATT&CK page ↗

T1557Adversary-in-the-Middle×1

Adversaries may attempt to position themselves between two or more networked devices using an adversary-in-the-middle (AiTM) technique to support follow-on behaviors such as Network Sniffing, Transmitted Data Manipulation, or replay attacks (Exploitation for Credential Access). By abusing features of common networking protocols that can determine the flow of network traffic (e.g. ARP, DNS, LLMNR, etc.), adversaries may force a device to communicate through an adversary controlled system so they can collect information or perform additional actions.

Evidence: 2026-07-29/talos-ir-trends-q2-2026-rmm-weaponization-auth-abuse · ATT&CK page ↗

T1606Forge Web Credentials×1

Adversaries may forge credential materials that can be used to gain access to web applications or Internet services. Web applications and services (hosted in cloud SaaS environments or on-premise servers) often use session cookies, tokens, or other materials to authenticate and authorize user access.

Evidence: 2026-07-14/microsoft-july-2026-patch-tuesday-two-exploited-zero-days · ATT&CK page ↗

T1621Multi-Factor Authentication Request Generation×1

Adversaries may attempt to bypass multi-factor authentication (MFA) mechanisms and gain access to accounts by generating MFA requests sent to users.

Evidence: 2026-07-29/talos-ir-trends-q2-2026-rmm-weaponization-auth-abuse · ATT&CK page ↗

Discovery TA0007

T1082System Information Discovery×1

An adversary may attempt to get detailed information about the operating system and hardware, including version, patches, hotfixes, service packs, and architecture. Adversaries may use this information to shape follow-on behaviors, including whether or not the adversary fully infects the target and/or attempts specific actions. This behavior is distinct from Local Storage Discovery which is an adversary's discovery of local drive, disks and/or volumes.

Evidence: 2026-09-07/recordedfuture-h1-2026-tool-stack-reuse · ATT&CK page ↗

T1087.002Account Discovery: Domain Account×2

Adversaries may attempt to get a listing of domain accounts. This information can help adversaries determine which domain accounts exist to aid in follow-on behavior such as targeting specific accounts which possess particular privileges.

Evidence: 2026-10-03/warlock-longlegs-sharepoint-machinekey-sysvol-ransomware · 2026-07-14/microsoft-july-2026-patch-tuesday-two-exploited-zero-days · ATT&CK page ↗

T1482Domain Trust Discovery×1

Adversaries may attempt to gather information on domain trust relationships that may be used to identify lateral movement opportunities in Windows multi-domain/forest environments. Domain trusts provide a mechanism for a domain to allow access to resources based on the authentication procedures of another domain. Domain trusts allow the users of the trusted domain to access resources in the trusting domain. The information discovered may help the adversary conduct SID-History Injection, Pass the Ticket, and Kerberoasting. Domain trusts can be enumerated using the `DSEnumerateDomainTrusts()` Win32 API call, .NET methods, and LDAP. The Windows utility Nltest is known to be used by adversaries to enumerate domain trusts.

Evidence: 2026-10-03/warlock-longlegs-sharepoint-machinekey-sysvol-ransomware · ATT&CK page ↗

Lateral Movement TA0008

T1021.001Remote Services: Remote Desktop Protocol×1

Adversaries may use Valid Accounts to log into a computer using the Remote Desktop Protocol (RDP). The adversary may then perform actions as the logged-on user.

Evidence: 2026-07-29/talos-ir-trends-q2-2026-rmm-weaponization-auth-abuse · ATT&CK page ↗

T1021.006Remote Services: Windows Remote Management×1

Adversaries may use Valid Accounts to interact with remote systems using Windows Remote Management (WinRM). The adversary may then perform actions as the logged-on user.

Evidence: 2026-07-29/talos-ir-trends-q2-2026-rmm-weaponization-auth-abuse · ATT&CK page ↗

T1534Internal Spearphishing×1

After they already have access to accounts or systems within the environment, adversaries may use internal spearphishing to gain access to additional information or compromise other users within the same organization. Internal spearphishing is multi-staged campaign where a legitimate account is initially compromised either by controlling the user's device or by compromising the account credentials of the user. Adversaries may then attempt to take advantage of the trusted internal account to increase the likelihood of tricking more victims into falling for phish attempts, often incorporating Impersonation.

Evidence: 2026-07-29/talos-ir-trends-q2-2026-rmm-weaponization-auth-abuse · ATT&CK page ↗

T1550.001Use Alternate Authentication Material: Application Access Token×1

Adversaries may use stolen application access tokens to bypass the typical authentication process and access restricted accounts, information, or services on remote systems. These tokens are typically stolen from users or services and used in lieu of login credentials.

Evidence: 2026-07-14/microsoft-july-2026-patch-tuesday-two-exploited-zero-days · ATT&CK page ↗

T1570Lateral Tool Transfer×1

Adversaries may transfer tools or other files between systems in a compromised environment. Once brought into the victim environment (i.e., Ingress Tool Transfer) files may then be copied from one system to another to stage adversary tools or other files over the course of an operation.

Evidence: 2026-10-03/warlock-longlegs-sharepoint-machinekey-sysvol-ransomware · ATT&CK page ↗

Collection TA0009

T1005Data from Local System×1

Adversaries may search local system sources, such as file systems, configuration files, local databases, virtual machine files, or process memory, to find files of interest and sensitive data prior to Exfiltration.

Evidence: 2026-09-07/recordedfuture-h1-2026-tool-stack-reuse · ATT&CK page ↗

T1213.002Data from Information Repositories: Sharepoint×2

Adversaries may leverage the SharePoint repository as a source to mine valuable information. SharePoint will often contain useful information for an adversary to learn about the structure and functionality of the internal network and systems. For example, the following is a list of example information that may hold potential value to an adversary and may also be found on SharePoint:

Evidence: 2026-07-18/abbott-exact-sciences-shinyhunters-entra-sso-vishing · 2026-07-10/helix-data-extortion-devicecode-vishing-sharepoint-exfil · ATT&CK page ↗

T1530Data from Cloud Storage×1

Adversaries may access data from cloud storage.

Evidence: 2026-07-18/abbott-exact-sciences-shinyhunters-entra-sso-vishing · ATT&CK page ↗

T1557Adversary-in-the-Middle×1

Adversaries may attempt to position themselves between two or more networked devices using an adversary-in-the-middle (AiTM) technique to support follow-on behaviors such as Network Sniffing, Transmitted Data Manipulation, or replay attacks (Exploitation for Credential Access). By abusing features of common networking protocols that can determine the flow of network traffic (e.g. ARP, DNS, LLMNR, etc.), adversaries may force a device to communicate through an adversary controlled system so they can collect information or perform additional actions.

Evidence: 2026-07-29/talos-ir-trends-q2-2026-rmm-weaponization-auth-abuse · ATT&CK page ↗

Command and Control TA0011

T1071.001Application Layer Protocol: Web Protocols×2

Adversaries may communicate using application layer protocols associated with web traffic to avoid detection/network filtering by blending in with existing traffic. Commands to the remote system, and often the results of those commands, will be embedded within the protocol traffic between the client and server.

Evidence: 2026-09-07/recordedfuture-h1-2026-tool-stack-reuse · 2026-07-29/talos-ir-trends-q2-2026-rmm-weaponization-auth-abuse · ATT&CK page ↗

T1102Web Service×1

Adversaries may use an existing, legitimate external Web service as a means for relaying data to/from a compromised system. Popular websites, cloud services, and social media acting as a mechanism for C2 may give a significant amount of cover due to the likelihood that hosts within a network are already communicating with them prior to a compromise. Using common services, such as those offered by Google, Microsoft, or Twitter, makes it easier for adversaries to hide in expected noise. Web service providers commonly use SSL/TLS encryption, giving adversaries an added level of protection.

Evidence: 2026-07-29/talos-ir-trends-q2-2026-rmm-weaponization-auth-abuse · ATT&CK page ↗

T1105Ingress Tool Transfer×3

Adversaries may transfer tools or other files from an external system into a compromised environment. Tools or files may be copied from an external adversary-controlled system to the victim network through the command and control channel or through alternate protocols such as ftp. Once present, adversaries may also transfer/spread tools between victim devices within a compromised environment (i.e. Lateral Tool Transfer).

Evidence: 2026-10-03/warlock-longlegs-sharepoint-machinekey-sysvol-ransomware · 2026-09-07/recordedfuture-h1-2026-tool-stack-reuse · 2026-08-06/canton-graubuenden-sharepoint-server-breach · ATT&CK page ↗

T1219Remote Access Tools×1

An adversary may use legitimate remote access tools to establish an interactive command and control channel within a network. Remote access tools create a session between two trusted hosts through a graphical interface, a command line interaction, a protocol tunnel via development or management software, or hardware-level access such as KVM (Keyboard, Video, Mouse) over IP solutions. Desktop support software (usually graphical interface) and remote management software (typically command line interface) allow a user to control a computer remotely as if they are a local user inheriting the user or software permissions. This software is commonly used for troubleshooting, software installation, and system management. Adversaries may similarly abuse response features included in EDR and other defensive tools that enable remote access.

Evidence: 2026-07-29/talos-ir-trends-q2-2026-rmm-weaponization-auth-abuse · ATT&CK page ↗

T1219.001Remote Access Tools: IDE Tunneling×1

Adversaries may abuse Integrated Development Environment (IDE) software with remote development features to establish an interactive command and control channel on target systems within a network. IDE tunneling combines SSH, port forwarding, file sharing, and debugging into a single secure connection, letting developers work on remote systems as if they were local. Unlike SSH and port forwarding, IDE tunneling encapsulates an entire session and may use proprietary tunneling protocols alongside SSH, allowing adversaries to blend in with legitimate development workflows. Some IDEs, like Visual Studio Code, also provide CLI tools (e.g., `code tunnel`) that adversaries may use to programmatically establish tunnels and generate web-accessible URLs for remote access. These tunnels can be authenticated through accounts such as GitHub, enabling the adversary to control the compromised system via a legitimate developer portal.

Evidence: 2026-10-03/warlock-longlegs-sharepoint-machinekey-sysvol-ransomware · ATT&CK page ↗

Exfiltration TA0010

T1041Exfiltration Over C2 Channel×1

Adversaries may steal data by exfiltrating it over an existing command and control channel. Stolen data is encoded into the normal communications channel using the same protocol as command and control communications.

Evidence: 2026-09-07/recordedfuture-h1-2026-tool-stack-reuse · ATT&CK page ↗

T1567Exfiltration Over Web Service×1

Adversaries may use an existing, legitimate external Web service to exfiltrate data rather than their primary command and control channel. Popular Web services acting as an exfiltration mechanism may give a significant amount of cover due to the likelihood that hosts within a network are already communicating with them prior to compromise. Firewall rules may also already exist to permit traffic to these services.

Evidence: 2026-07-29/talos-ir-trends-q2-2026-rmm-weaponization-auth-abuse · ATT&CK page ↗

Impact TA0040

T1486Data Encrypted for Impact×2

Adversaries may encrypt data on target systems or on large numbers of systems in a network to interrupt availability to system and network resources. They can attempt to render stored data inaccessible by encrypting files or data on local and remote drives and withholding access to a decryption key. This may be done in order to extract monetary compensation from a victim in exchange for decryption or a decryption key (ransomware) or to render data permanently inaccessible in cases where the key is not saved or transmitted.

Evidence: 2026-10-03/warlock-longlegs-sharepoint-machinekey-sysvol-ransomware · 2026-07-29/talos-ir-trends-q2-2026-rmm-weaponization-auth-abuse · ATT&CK page ↗

Entries about Microsoft SharePoint (10)

2026-10-03 · view entry permalink →

HIGHNATOB2

Longlegs (Storm-2603), the developer of Warlock ransomware, still enters through on-premises SharePoint: a water utility, a telecom, a regional government body and a university hit in two months

Symantec reports that Longlegs, also known as Storm-2603, develops the Warlock ransomware and attacked at least four organizations in two months: a water utility, a telecommunications provider, a regional government body and a university, in Portuguese- and Spanish-speaking countries (Symantec, 2026-10-01). Symantec says the group typically enters through on-premises SharePoint Server, and that the 2025 ToolShell flaws (CVE-2025-49704, CVE-2025-49706, CVE-2025-53770 and CVE-2025-53771) likely remain in its arsenal alongside newer SharePoint flaws (Symantec, 2026-10-01); BleepingComputer relays the report (BleepingComputer, 2026-10-02).

In the intrusion Symantec walks through, the likely entry was SharePoint exploitation, and on 2026-07-22 PowerShell wrote a web shell into the SharePoint LAYOUTS template directory (Symantec, 2026-10-01). The group drops one into the directories of several SharePoint versions at once; it harvests the farm's ASP.NET machine keys, which the attackers use to forge a validly signed payload that runs code in the SharePoint application pool (Symantec, 2026-10-01). From 2026-07-28 PowerShell commands loading the System.Workflow.ComponentModel assembly, the deserialization gadget behind the forged payload, ran at intervals (Symantec, 2026-10-01). The attackers also used DLL sideloading, fetched installers with msiexec from legitimate cloud file-sharing services, enumerated domain accounts and trusts, added a setup-lookalike domain account to local Administrators on three more hosts, installed Visual Studio Code Insiders as a tunnel service, and ran NetExec for enumeration, credential spraying and remote execution (Symantec, 2026-10-01).

On 2026-07-31 a security-tool killer, pushed with one-line commands that copied a tool set from an internal share, ran on at least 40 hosts in about two hours; its driver is unknown, but in other recent attacks the group used the signed K7RKScan driver (CVE-2025-1055) (Symantec, 2026-10-01). Warlock then ran on at least 33 hosts from the domain's SYSVOL scripts share, with the DFS Replication service (dfsrs.exe) as the parent on three hosts, so SYSVOL replication delivered the payload (Symantec, 2026-10-01).

Triage: Visual Studio Code tunnels are ordinary on developer workstations; the observed pattern is a service installed from a system folder on a host in a domain already showing SharePoint exploitation or an unexpected administrator account (Symantec, 2026-10-01).

In the past two months, Longlegs has attacked at least four organizations, including two critical infrastructure operators (a water utility and a telecommunications provider), a regional government body, and a university.

The webshell's function is to harvest the SharePoint farm's ASP.NET machine keys, which the attackers then use to forge a validly signed payload that achieves remote code execution inside the SharePoint application pool.

In one intrusion against a critical infrastructure operator, the attackers pushed a tool designed to disable security software to at least 40 hosts within about two hours, then deployed Warlock on at least 33 hosts by staging it in the domain's SYSVOL share, where ordinary domain replication delivered it to machines.

Symantec Threat Hunter Team / Carbon Black 2026-10-01

Builds on: Swiss federal SharePoint servers breached mid-patching, ~200 accounts taken, servers now being… · A second Swiss public-sector SharePoint victim in 48 hours, and the intrusion sat unnoticed for…

threat03 Oct 04:41Zsingle-sourceOpen finding →

2026-09-26 · view entry permalink →

HIGHCVE-2026-65660exploitedNATOA1

CVE-2026-65660, Microsoft SharePoint: a SafeControls parser-desync lets an authenticated attacker forge a second Register directive and reach RCE via in-memory XAML deserialization, now confirmed exploited (CVSS 8.8)

CISA added CVE-2026-65660 to its Known Exploited Vulnerabilities catalog on 2026-09-25 (CISA, 2026-09-25), and its KEV catalog data feed carries the field forensicTriage: Yes for this CVE; CISA's own designation for entries where its Forensics Triage Requirements guidance applies before remediation (CISA Known Exploited Vulnerabilities Catalog, JSON feed, 2026-09-25). The same day, Microsoft revised its own CVE record to state plainly: "As of 9/25/2026, Microsoft had reliable evidence of observed attacks against exploitation of this vulnerability" (Microsoft Security Response Center, 2026-09-25), a reversal of the exploitability assessment Microsoft's own advisory carried "at the time of original publication," "Exploitation Less Likely" (Microsoft Security Response Center, 2026-09-25). Microsoft's own revision log separately records a 27 August 2026 update to the record's Impact, CVE Title and FAQs, described only as "an informational change," with no prior value stated. The bug sits in SharePoint's ToolPane.GetPartPreviewAndPropertiesFromMarkup(), which checks a web part's Register directive against the SafeControls allow-list before parsing it; because RegisterDirective.GetHtml() writes attribute values inside double quotes without escaping embedded quote characters, an attacker can split a directive's Src attribute across the quote boundary to smuggle a second, unchecked Register directive into the markup after the SafeControls check has already run, registering an arbitrary .NET class (Viettel Cyber Security, Dinh Ho Anh Khoa, 2026-09-22). Wrapping System.Xaml.XamlServices in an ExpandedWrapper and invoking XamlServices.Parse() on an ObjectDataProvider gadget then yields what the researcher terms an "in-memory webshell", repeatable code execution held entirely in the worker process's memory, with no file written to disk (Viettel Cyber Security, 2026-09-22). The base bug needs only low-privilege authentication and no user interaction (MSRC FAQ, 2026-09-25), and Viettel's public write-up includes the working exploit markup itself; the same researcher separately showed ToolPane's own authentication check can be bypassed via a distinct, already-patched (9 June 2026) flaw, and Canada's Cyber Centre confirms the pair chains to pre-authentication RCE on SharePoint servers configured for anonymous access (Canadian Centre for Cyber Security, AL26-023, 2026-09-24). Fixed since the 11 August 2026 cumulative update, which also disables the vulnerable function by default; the discloser separately states the underlying bug affects SharePoint 2013 as well, a version Microsoft's own CVE record does not address. Canada's Cyber Centre separately flags that SharePoint Enterprise Server 2016 and Server 2019 themselves reached end of life on 15 July 2026 and urges migration to a supported version (Canadian Centre for Cyber Security, AL26-023, 2026-09-24).

Because no file-based web shell is dropped, file-integrity monitoring of the wwwroot tree will not catch this technique. Canada's Cyber Centre recommends monitoring for unusual SharePoint administrative activity or suspicious authenticated access attempts, watching for Microsoft Defender or AMSI detections tied to SharePoint exploitation activity, and conducting ongoing log and security monitoring of SharePoint, IIS, endpoint security and authentication logs (Canadian Centre for Cyber Security, AL26-023, 2026-09-24).

Triage: ordinary SharePoint web-part usage never registers a second, unchecked control after the SafeControls check has already passed on the same request, a Register directive whose Src attribute value contains an embedded, unescaped quote character is itself the anomaly, distinct from routine web-part edits which SharePoint's own markup generation never produces.

As of 9/25/2026, Microsoft had reliable evidence of observed attacks against exploitation of this vulnerability.

Microsoft Security Response Center 2026-09-25

Chained with other SharePoint vulnerabilities, this vulnerability can achieve pre-authentication remote code execution on SharePoint servers configured to permit anonymous access.

Canadian Centre for Cyber Security, AL26-023

An authenticated attacker with low-level access to an affected server could send a specially crafted request to execute code on the server. User interaction is not required.

Microsoft Security Response Center FAQ
vulnerability26 Sep 04:04Zmulti-sourceOpen finding →

2026-09-07 · view entry permalink →

NOTABLENATOB2

Recorded Future's H1 2026 Malware and Vulnerability Trends: two clusters reuse an identical post-exploitation tool stack across thirteen and ten unrelated initial CVEs

Recorded Future's Insikt Group published its H1 2026 Malware and Vulnerability Trends report on 3 September 2026, tracking 215 actively exploited CVEs in the first half of 2026, up 34% from 161 in H1 2025 (Recorded Future, 2026-09-03). Of those, 176 (82%) were network-accessible and 146 (68%) could be exploited without prior authentication; 142 of those 146 combined both properties, and 60 of 82 remote-code-execution CVEs combined network reachability, no authentication requirement and code execution in a single package (Recorded Future, 2026-09-03).

The report's most actionable finding for defenders is that post-exploitation tool-stack reuse persists across otherwise-unrelated initial-access vulnerabilities, regardless of vendor or product family (Recorded Future, 2026-09-03). A cluster the report designates StrikeShark applied an identical six-tool post-exploitation stack (SharkLoader, Cobalt Strike Beacon, FScan, Searchall, Pillager Stealer and SharpGPOAbuse) across thirteen separate CVEs spanning 2016 through 2025, reaching Microsoft Exchange, Microsoft SharePoint, Fortinet FortiOS, Cisco IOS XE, F5 BIG-IP, GeoServer and Apache Shiro (Recorded Future, 2026-09-03); SharkLoader itself was previously profiled by Kaspersky's GReAT, which found it deploying Cobalt Strike via "Perfect DLL Hijacking" in a campaign whose confirmed victims spanned government and diplomatic entities, software developers and organizations in several other sectors and regions (Kaspersky Securelist, 2026-06-24). Separately, Storm-1175 linked Mimikatz, Impacket, PsExec, Rclone and Medusa ransomware across ten different initial CVEs; a China-linked cluster the report designates SHADOW-EARTH-053 separately reused Mimikatz following exploitation of CVE-2021-26855 in Microsoft Exchange Server (Recorded Future, 2026-09-03). Insikt Group mapped 114 of the 215 CVEs to MITRE ATT&CK: exploitation of a public-facing application was associated with 77 CVEs (68%), and 50 of those 77 also co-occurred with PowerShell, Windows Command Shell or Unix Shell execution; every one of the 28 web-shell-associated CVEs also carried the public-facing-application technique. The next most frequently associated post-exploitation behaviors across the mapped CVEs were system-information discovery, collection of data from the local system, transfer of further tooling into the compromised environment, and exfiltration over the command-and-control channel or web-protocol-based C2 traffic (Recorded Future, 2026-09-03).

The report's own defender-facing conclusion is explicit: because the same limited tool stack recurs regardless of which vulnerability supplied the initial foothold, detection engineering should chain exploitation telemetry from public-facing systems through to the post-exploitation behaviors these clusters repeat (credential dumping, remote-service execution via native administration mechanisms, bulk outbound data transfer, and ransomware staging) rather than treating each CVE alert as an isolated, one-off event (Recorded Future, 2026-09-03).

Threat actors reused post-exploitation playbooks across different initial vulnerabilities; StrikeShark applied the same six-tool stack across thirteen CVEs, while Storm-1175 linked credential theft, remote execution, data transfer, and ransomware tooling across ten.

In the StrikeShark campaign, SharkLoader, Cobalt Strike Beacon, FScan, Searchall, Pillager Stealer, and SharpGPOAbuse were linked to the same thirteen CVEs. Those vulnerabilities spanned 2016 through 2025 and affected Microsoft Exchange and SharePoint, Fortinet FortiOS, Cisco IOS XE, F5 BIG-IP, GeoServer, Apache Shiro, and other public-facing technologies.

50 of the 77 CVEs associated with the exploitation of public-facing applications were also linked to PowerShell, Windows Command Shell, or Unix Shell, and all 28 web-shell-associated CVEs also included T1190.

Recorded Future (Insikt Group) 2026-09-03

Builds on: Kaspersky GReAT: "StrikeShark" loader deploys Cobalt Strike via "Perfect DLL Hijacking" against…

annual-report07 Sep 04:43Zsingle-sourceOpen finding →

Earlier coverage (7)

2026-07-14HIGHexploitedupdatedNATOA1Microsoft July 2026 Patch Tuesday ships two actively-exploited zero-days, AD FS local EoP (CVE-2026-56155) and unauthenticated SharePoint EoP (CVE-2026-56164)Microsoft's July 2026 Patch Tuesday (its largest ever by CVE count) fixes two zero-days Microsoft confirms were exploited in the wild and CISA added to KEV the same day: CVE-2026-56155, a local elevation-of-privilege in Active Directory Federation Services (AD FS), and CVE-2026-56164, an unauthenticated, network-reachable elevation-of-privilege in on-prem SharePoint Server 2016/2019/Subscription Edition. Any organization running on-prem AD FS or SharePoint should treat both as emergency patches.2026-07-02HIGHexploitedupdatedCVE-2026-45659, Microsoft SharePoint Server: authenticated deserialization RCE, now KEV-listedCISA flags a SharePoint RCE Microsoft downplayed. CISA added CVE-2026-45659 (SharePoint Server deserialization-of-untrusted-data RCE, CVSS 8.8, Site-Member-authenticated) to its Known Exploited Vulnerabilities catalog on 1 July, the first public confirmation of active exploitation for a bug Microsoft's own advisory still rates "Exploitation Less Likely" and quietly patched on 21 May (Microsoft MSRC). On-prem SharePoint operators who deferred the May fix should treat it as live.2026-08-06HIGHexploitedNATOA2Canton Graubünden discloses a SharePoint server breach a day after the Confederation did; the on-premises wave has reached Swiss cantonal governmentThe IT office of the Swiss canton of Graubünden disclosed on 2026-08-05 (one day after Switzerland's federal IT provider BIT disclosed an intrusion into its own on-premises SharePoint estate) that a SharePoint server hosting the cantonal administration's public web presence was compromised on the afternoon of 29 July 2026. Two files were placed on the cantonal server but their code was not executed, and a first analysis found no compromised accounts and no data exfiltration; confidential and specially-protected personal data are not held on those servers. The canton's IT chief says it could be the same vulnerability found at federal level, but neither Swiss disclosure names a CVE, and the canton shipped an out-of-band update on the evening of 5 August.2026-08-05HIGHexploitedNATOA2Switzerland's federal IT provider BIT confirms a SharePoint Server intrusion: ~200 federal user and technical accounts compromised while the July patches were already being installedThe Bundesamt für Informatik und Telekommunikation (BIT), which runs the Swiss Confederation's own data centres, disclosed on 2026-08-04 that its on-premises Microsoft SharePoint Servers were compromised by unknown actors, presumably through the SharePoint flaws Microsoft disclosed in mid-July 2026, and that the credentials of roughly 200 accounts (user accounts and technical service accounts) were taken. BIT had begun installing the July updates immediately after release; staff spotted anomalies on 28 July and confirmed credential compromise on 31 July. Passwords were reset, internet access to SharePoint is blocked for non-federal users, and the affected servers are being rebuilt from scratch rather than patched in place.2026-07-18NOTABLEupdatedNATOA3Abbott confirms a Cancer Diagnostics cyber incident; ShinyHunters claims a vished Entra SSO account and 30M+ recordsAbbott Laboratories confirmed (2026-07-16) unauthorized access to a limited number of internal systems in its Cancer Diagnostics business (the acquired Exact Sciences unit) only. Separately, the ShinyHunters extortion group claims the intrusion began with a vishing call that compromised a Microsoft Entra ID single-sign-on account, then used it to pull 30M+ records from Entra, ServiceNow, SharePoint, Databricks and Coupa; a claim Abbott has neither confirmed nor attributed. The confirmed incident plus the same vishing-to-cloud-SSO tradecraft this actor uses against SaaS-integrated enterprises makes it relevant to healthcare and any SharePoint/Entra-dependent estate.2026-07-29NOTABLENATOB2Talos IR Trends Q2 2026: ransomware operators ran their command-and-control through legitimate RMM agents, authentication abuse hit two-thirds of engagements, and missing logs stopped root-cause determination outrightCisco Talos Incident Response published its Q2 2026 quarterly report on 2026-07-28. Three named chains carry the operational value: Sinobi ransomware, in Talos IR's first engagement with the group, used a trojanized MeshAgent binary installed as a SYSTEM auto-start service for encrypted-WebSocket C2, held access for about three days, cracked a weak service-account password from ntds.dit, moved by RDP and WinRM, and deployed ransomware across the entire domain through a malicious GPO logon script with rclone staging exfiltration; Warlock (Storm-2603) was seen deploying the Zoho Assist Unattended Agent, a tool Talos had not previously attributed to it; and UAT-11764 runs a QR-code-in-PDF phishing operation that propagates through each compromised mailbox's own contact list. Two findings cut across all of it, authentication abuse appeared in 65% of engagements, and in several cases logging gaps prevented Talos from determining the initial access vector or the scope of exfiltration at all.2026-07-10HIGHNATOB2'Helix' data-extortion cluster pairs manager-impersonation vishing with device-code phishing and automated SharePoint exfiltrationReliaQuest documented a previously unreported data-extortion cluster it calls Helix, assessed as a likely continuation of the BlackFile (UNC6671) and ShinyHunters ecosystems on shared registrar and hosting infrastructure. Operators phone a target impersonating their named manager (spoofed caller-ID), walk them through an Entra ID device-code sign-in that captures a session token without a password and sidesteps Conditional Access, register a new Authenticator within minutes for persistence, then run automated SharePoint enumeration and bulk exfiltration. SharePoint + Entra ID is the default identity/collaboration stack across Swiss and EU public-sector tenants, so the playbook is directly reachable; disabling the device-code flow is the single highest-impact control.

Co-occurring entities

Derived: referenced by the same focused operational entries (weekly summaries and report roundups don't count); ×N counts the shared entries.

Where this entity is cited

  • Threats4
  • Vulns3
  • Deep dive2
  • Research1

Source distribution

  • msrc.microsoft.com9 (19%)
  • bleepingcomputer.com8 (17%)
  • cisa.gov3 (6%)
  • rapid7.com3 (6%)
  • abbott.com1 (2%)
  • admin.ch1 (2%)
  • advisories.ncsc.nl1 (2%)
  • api.first.org1 (2%)
  • other20 (43%)
All cited sources (47)