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Fortinet FortiGate

product · product:fortinet-fortigate single-source-national-cert

Coverage
2
first 2026-06-18 → last 2026-10-11
Latest activity
2026-10-08
FBI and Secret Service: FortiBleed is still active, locks admins out of FortiGates and feeds ransomware…
Peak priority
high
2 high
Targets
public-sector
sectors: public-sector, finance, telco · regions: europe
Sources cited
12
8 hosts

Action items (3)

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

Defender insights

What each entry about Fortinet FortiGate tells a defender to do, newest first.

2026-06-18HIGHexploitedFBI and Secret Service: FortiBleed is still active, locks admins out of FortiGates and feeds ransomware affiliates

Exposure · detection

2026-08-09HIGHA mobile-carrier private APN, shared by a wind farm and a heat plant, carried an attacker from a substation firewall to the turbine controls

Triage

Story timeline

  1. 2026-08-09CERT Polska: a second Polish CHP plant was shut down on 29 December 2025 through the distribution operator's private APN, the first real-world use of that path into an OT network
    deep-diveA mobile-carrier private APN, shared by a wind farm and a heat plant, carried an attacker from a substation firewall to the turbine controls
  2. 2026-06-18FortiBleed: an active credential-compromise campaign against internet-facing FortiGate firewalls, now locking administrators out and supplying ransomware affiliates
    active-threatsFBI and Secret Service: FortiBleed is still active, locks admins out of FortiGates and feeds ransomware affiliates

Hunting pivots

Releases covered
Fortinet FortiGate ×2
ATT&CK techniques (18 across 12 tactics)

18 techniques observed across 2 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)

  • ReconnaissanceActive Scanning
  • Resource DevelopmentAcquire Infrastructure
  • Initial AccessValid Accounts · Valid Accounts: Default Accounts · External Remote Services
  • PersistenceValid Accounts · Valid Accounts: Default Accounts · External Remote Services · Create Account: Local Account
  • Privilege EscalationValid Accounts · Valid Accounts: Default Accounts
  • StealthIndicator Removal · Valid Accounts · Valid Accounts: Default Accounts
  • Credential AccessOS Credential Dumping · Brute Force: Password Cracking · Brute Force: Password Spraying · Brute Force: Credential Stuffing
  • DiscoveryNetwork Service Discovery · Account Discovery
  • Lateral MovementRemote Services: SSH
  • Command and ControlProtocol Tunneling
  • ExfiltrationExfiltration Over C2 Channel
  • ImpactAccount Access Removal · Disk Wipe: Disk Structure Wipe

Reconnaissance TA0043

T1595Active Scanning×1

Adversaries may execute active reconnaissance scans to gather information that can be used during targeting. Active scans are those where the adversary probes victim infrastructure via network traffic, as opposed to other forms of reconnaissance that do not involve direct interaction.

Evidence: 2026-06-18/fortibleed-73-932-internet-facing-fortigate-devices-exposed · ATT&CK page ↗

Resource Development TA0042

T1583Acquire Infrastructure×1

Adversaries may buy, lease, rent, or obtain infrastructure that can be used during targeting. A wide variety of infrastructure exists for hosting and orchestrating adversary operations. Infrastructure solutions include physical or cloud servers, domains, and third-party web services. Some infrastructure providers offer free trial periods, enabling infrastructure acquisition at limited to no cost. Additionally, botnets are available for rent or purchase.

Evidence: 2026-06-18/fortibleed-73-932-internet-facing-fortigate-devices-exposed · ATT&CK page ↗

Initial Access TA0001

T1078Valid Accounts×2

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: 2026-08-09/cert-polska-private-apn-pivot-into-ot-chp-plant-shutdown · 2026-06-18/fortibleed-73-932-internet-facing-fortigate-devices-exposed · ATT&CK page ↗

T1078.001Valid Accounts: Default Accounts×1

Adversaries may obtain and abuse credentials of a default account as a means of gaining Initial Access, Persistence, Privilege Escalation, or Defense Evasion. Default accounts are those that are built-into an OS, such as the Guest or Administrator accounts on Windows systems. Default accounts also include default factory/provider set accounts on other types of systems, software, or devices, including the root user account in AWS, the root user account in ESXi, and the default service account in Kubernetes.

Evidence: 2026-08-09/cert-polska-private-apn-pivot-into-ot-chp-plant-shutdown · ATT&CK page ↗

T1133External Remote Services×2

Adversaries may leverage external-facing remote services to initially access and/or persist within a network. Remote services such as VPNs, Citrix, and other access mechanisms allow users to connect to internal enterprise network resources from external locations. There are often remote service gateways that manage connections and credential authentication for these services. Services such as Windows Remote Management and VNC can also be used externally.

Evidence: 2026-08-09/cert-polska-private-apn-pivot-into-ot-chp-plant-shutdown · 2026-06-18/fortibleed-73-932-internet-facing-fortigate-devices-exposed · ATT&CK page ↗

Persistence TA0003

T1078Valid Accounts×2

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: 2026-08-09/cert-polska-private-apn-pivot-into-ot-chp-plant-shutdown · 2026-06-18/fortibleed-73-932-internet-facing-fortigate-devices-exposed · ATT&CK page ↗

T1078.001Valid Accounts: Default Accounts×1

Adversaries may obtain and abuse credentials of a default account as a means of gaining Initial Access, Persistence, Privilege Escalation, or Defense Evasion. Default accounts are those that are built-into an OS, such as the Guest or Administrator accounts on Windows systems. Default accounts also include default factory/provider set accounts on other types of systems, software, or devices, including the root user account in AWS, the root user account in ESXi, and the default service account in Kubernetes.

Evidence: 2026-08-09/cert-polska-private-apn-pivot-into-ot-chp-plant-shutdown · ATT&CK page ↗

T1133External Remote Services×2

Adversaries may leverage external-facing remote services to initially access and/or persist within a network. Remote services such as VPNs, Citrix, and other access mechanisms allow users to connect to internal enterprise network resources from external locations. There are often remote service gateways that manage connections and credential authentication for these services. Services such as Windows Remote Management and VNC can also be used externally.

Evidence: 2026-08-09/cert-polska-private-apn-pivot-into-ot-chp-plant-shutdown · 2026-06-18/fortibleed-73-932-internet-facing-fortigate-devices-exposed · ATT&CK page ↗

T1136.001Create Account: Local Account×1

Adversaries may create a local account to maintain access to victim systems. Local accounts are those configured by an organization for use by users, remote support, services, or for administration on a single system or service.

Evidence: 2026-06-18/fortibleed-73-932-internet-facing-fortigate-devices-exposed · ATT&CK page ↗

Privilege Escalation TA0004

T1078Valid Accounts×2

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: 2026-08-09/cert-polska-private-apn-pivot-into-ot-chp-plant-shutdown · 2026-06-18/fortibleed-73-932-internet-facing-fortigate-devices-exposed · ATT&CK page ↗

T1078.001Valid Accounts: Default Accounts×1

Adversaries may obtain and abuse credentials of a default account as a means of gaining Initial Access, Persistence, Privilege Escalation, or Defense Evasion. Default accounts are those that are built-into an OS, such as the Guest or Administrator accounts on Windows systems. Default accounts also include default factory/provider set accounts on other types of systems, software, or devices, including the root user account in AWS, the root user account in ESXi, and the default service account in Kubernetes.

Evidence: 2026-08-09/cert-polska-private-apn-pivot-into-ot-chp-plant-shutdown · ATT&CK page ↗

Stealth TA0005

T1070Indicator Removal×1

Adversaries may selectively delete or modify artifacts generated to reduce indications of their presence and blend in with legitimate activity. Rather than broadly removing evidence, adversaries may target specific artifacts that appear anomalous or are likely to draw scrutiny, while leaving sufficient data intact to maintain the appearance of normal system behavior.

Evidence: 2026-08-09/cert-polska-private-apn-pivot-into-ot-chp-plant-shutdown · ATT&CK page ↗

T1078Valid Accounts×2

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: 2026-08-09/cert-polska-private-apn-pivot-into-ot-chp-plant-shutdown · 2026-06-18/fortibleed-73-932-internet-facing-fortigate-devices-exposed · ATT&CK page ↗

T1078.001Valid Accounts: Default Accounts×1

Adversaries may obtain and abuse credentials of a default account as a means of gaining Initial Access, Persistence, Privilege Escalation, or Defense Evasion. Default accounts are those that are built-into an OS, such as the Guest or Administrator accounts on Windows systems. Default accounts also include default factory/provider set accounts on other types of systems, software, or devices, including the root user account in AWS, the root user account in ESXi, and the default service account in Kubernetes.

Evidence: 2026-08-09/cert-polska-private-apn-pivot-into-ot-chp-plant-shutdown · ATT&CK page ↗

Credential Access TA0006

T1003OS Credential Dumping×1

Adversaries may attempt to dump credentials to obtain account login and credential material, normally in the form of a hash or a clear text password. Credentials can be obtained from OS caches, memory, or structures. Credentials can then be used to perform Lateral Movement and access restricted information.

Evidence: 2026-06-18/fortibleed-73-932-internet-facing-fortigate-devices-exposed · ATT&CK page ↗

T1110.002Brute Force: Password Cracking×1

Adversaries may use password cracking to attempt to recover usable credentials, such as plaintext passwords, when credential material such as password hashes are obtained. OS Credential Dumping can be used to obtain password hashes, this may only get an adversary so far when Pass the Hash is not an option. Further, adversaries may leverage Data from Configuration Repository in order to obtain hashed credentials for network devices.

Evidence: 2026-06-18/fortibleed-73-932-internet-facing-fortigate-devices-exposed · 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: 2026-06-18/fortibleed-73-932-internet-facing-fortigate-devices-exposed · ATT&CK page ↗

T1110.004Brute Force: Credential Stuffing×1

Adversaries may use credentials obtained from breach dumps of unrelated accounts to gain access to target accounts through credential overlap. Occasionally, large numbers of username and password pairs are dumped online when a website or service is compromised and the user account credentials accessed. The information may be useful to an adversary attempting to compromise accounts by taking advantage of the tendency for users to use the same passwords across personal and business accounts.

Evidence: 2026-06-18/fortibleed-73-932-internet-facing-fortigate-devices-exposed · ATT&CK page ↗

Discovery TA0007

T1046Network Service Discovery×1

Adversaries may attempt to get a listing of services running on remote hosts and local network infrastructure devices, including those that may be vulnerable to remote software exploitation. Common methods to acquire this information include port, vulnerability, and/or wordlist scans using tools that are brought onto a system.

Evidence: 2026-08-09/cert-polska-private-apn-pivot-into-ot-chp-plant-shutdown · ATT&CK page ↗

T1087Account Discovery×1

Adversaries may attempt to get a listing of valid accounts, usernames, or email addresses on a system or within a compromised environment. This information can help adversaries determine which accounts exist, which can aid in follow-on behavior such as brute-forcing, spear-phishing attacks, or account takeovers (e.g., Valid Accounts).

Evidence: 2026-06-18/fortibleed-73-932-internet-facing-fortigate-devices-exposed · ATT&CK page ↗

Lateral Movement TA0008

T1021.004Remote Services: SSH×1

Adversaries may use Valid Accounts to log into remote machines using Secure Shell (SSH). The adversary may then perform actions as the logged-on user.

Evidence: 2026-08-09/cert-polska-private-apn-pivot-into-ot-chp-plant-shutdown · ATT&CK page ↗

Command and Control TA0011

T1572Protocol Tunneling×1

Adversaries may tunnel network communications to and from a victim system within a separate protocol to avoid detection/network filtering and/or enable access to otherwise unreachable systems. Tunneling involves explicitly encapsulating a protocol within another. This behavior may conceal malicious traffic by blending in with existing traffic and/or provide an outer layer of encryption (similar to a VPN). Tunneling could also enable routing of network packets that would otherwise not reach their intended destination, such as SMB, RDP, or other traffic that would be filtered by network appliances or not routed over the Internet.

Evidence: 2026-08-09/cert-polska-private-apn-pivot-into-ot-chp-plant-shutdown · 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: 2026-06-18/fortibleed-73-932-internet-facing-fortigate-devices-exposed · ATT&CK page ↗

Impact TA0040

T1531Account Access Removal×2

Adversaries may interrupt availability of system and network resources by inhibiting access to accounts utilized by legitimate users. Accounts may be deleted, locked, or manipulated (ex: changed credentials, revoked permissions for SaaS platforms such as Sharepoint) to remove access to accounts. Adversaries may also subsequently log off and/or perform a System Shutdown/Reboot to set malicious changes into place.

Evidence: 2026-08-09/cert-polska-private-apn-pivot-into-ot-chp-plant-shutdown · 2026-06-18/fortibleed-73-932-internet-facing-fortigate-devices-exposed · ATT&CK page ↗

T1561.002Disk Wipe: Disk Structure Wipe×1

Adversaries may corrupt or wipe the disk data structures on a hard drive necessary to boot a system; targeting specific critical systems or in large numbers in a network to interrupt availability to system and network resources.

Evidence: 2026-08-09/cert-polska-private-apn-pivot-into-ot-chp-plant-shutdown · ATT&CK page ↗

Entries about Fortinet FortiGate (2)

2026-06-18 · view entry permalink →

HIGHexploitedupdatedNATOA1

FortiBleed: an active credential-compromise campaign against internet-facing FortiGate firewalls, now locking administrators out and supplying ransomware affiliates

A dataset branded "FortiBleed" was reported on 2026-06-18, containing 73,932 unique FortiGate management URLs, roughly 75,000 devices across 194 countries and 21,632 domains, paired with valid VPN and administrative credentials (BleepingComputer, 2026-06-18). Fortinet's position is that this is not a new Fortinet vulnerability: it believes threat actors are reusing credentials from previous incidents and using brute force against devices with weak password hygiene and no multi-factor authentication (Fortinet PSIRT, 2026-06-19). BleepingComputer reports researcher Bob Diachenko's claim that a Russian-speaking multi-operator group harvested the credentials, cracked intercepted SSL VPN hashes on a 45-GPU cluster and moved laterally into internal Active Directory environments, with several organisations fully compromised; Diachenko says he drew this from files the attackers left exposed on the same server (BleepingComputer, 2026-06-18); Arctic Wolf is separately tracking the FortiBleed campaign's reach across 194 countries (Arctic Wolf, 2026-06-17). The technique class is valid-account abuse following credential access, not exploitation of a fresh CVE.

which abuses FortiOS's built-in diagnose sniffer packet functionality to capture authentication traffic traversing compromised FortiGate devices

BleepingComputer

we believe the activity involves threat actors reusing credentials from previous incidents and employing brute-force techniques against devices with weak password hygiene and no multi-factor authentication (MFA)

SecurityWeek

The FBI says that in some incidents, the threat actor creates administrator accounts and uses their privileges to delete existing admin accounts or change their passwords, denying victims access to their devices.

Some groups benefiting from this are INC/Lynx ransomware and Payload ransomware.

BleepingComputer
Updaterun 2026-06-20-4cfd00efregionssourcestagsbody

The FortiBleed SSL VPN credential-harvesting campaign has grown from the 73,932 internet-facing FortiGate devices reported on 2026-06-18 to 86,644 confirmed compromised credentials across 194 countries, and CISA has published a hardening alert (SecurityWeek, 2026-06-19; CISA, 2026-06-18).

The new detail is methodology and impact, as researcher Bob Diachenko claims it: the operators intercept SSL VPN authentication, crack the hashes on a 45-GPU cluster managed through Hashtopolis and pivot into internal Active Directory environments (SecurityWeek, 2026-06-19; BleepingComputer, 2026-06-18). CISA's alert urges terminating active sessions and resetting credentials, storing administrator logins with PBKDF2, reviewing logs, enabling phishing-resistant MFA and locking down management access (SecurityWeek, 2026-06-19). Fortinet advises checking for unexpected administrator access from an unknown IP and reviewing domain controller logs for lateral movement (Fortinet PSIRT, 2026-06-19).

Updaterun 2026-06-23-165387f6evidencesectorssourcesbody

New analysis published 2026-06-22 gives a more detailed description of the tool chain behind the FortiBleed credential-harvesting campaign. SOCRadar's report, as BleepingComputer describes it, alleges a purpose-built Golang tool, FortigateSniffer, that abuses FortiOS's built-in diagnose sniffer packet command to capture authentication traffic on a compromised FortiGate, with a component named SNIFTRAN reconstructing the captured traffic into PCAP files and a Python toolkit extracting cleartext credentials, password hashes, Kerberos tickets and NTLM authentication material from them, across 24 protocols (BleepingComputer, 2026-06-22).

Fortinet's PSIRT response confirms the campaign uses no new vulnerability: it reuses credentials from the previously-disclosed CVE-2026-24858, CVE-2025-59718 and CVE-2025-59719 plus brute force against devices lacking strong passwords and MFA (Fortinet PSIRT, 2026-06-19; SecurityWeek, 2026-06-22). Reported tradecraft includes a distributed 36-GPU cluster rented from a GenAI company for offline cracking of the harvested hashes, according to researcher Kevin Beaumont (BleepingComputer, 2026-06-22), where Diachenko's earlier claim was a 45-GPU cluster managed through Hashtopolis (BleepingComputer, 2026-06-18); SOCRadar characterises the operators as Russian-speaking (SOCRadar, 2026-06-16).

The delta for defenders is a concrete detection surface that earlier coverage lacked: the tool connects to the FortiGate over SSH and launches the diagnose sniffer packet command (BleepingComputer, 2026-06-22), so hunt for unexpected invocations of that command on the appliance; because harvested Active Directory credentials are the downstream prize, any directory account a FortiBleed-corpus device authenticated against deserves to be treated as exposed, with domain controller logs reviewed for unusual access by those accounts (Fortinet PSIRT, 2026-06-19). Upgrade to firmware with PBKDF2 password hashing to make offline cracking expensive, terminate active sessions, enable MFA and disable external management access.

Updaterun 2026-10-08T0404Z-inteltitleheadlinesummarytagsentitiestechniquesaffected_productsclassificationsourcesevidencesourcing_noteactionsbody

A joint advisory of the FBI and the U.S. Secret Service (JCSA-20261006-01, 2026-10-06) calls FortiBleed an active, global credential-compromise campaign against internet-facing FortiGate firewalls and SSL VPN gateways, cites SOCRadar for more than 86,644 compromised devices in 194 countries, and says attackers are continuing to scan exposed devices with previously obtained credentials (FBI and U.S. Secret Service, 2026-10-06). The operators scan exposed SSL VPN portals, run credential stuffing and password spraying from earlier Fortinet leak dumps and infostealer logs, pull password hashes and session tokens from compromised devices and crack the hashes offline with Hashcat and Hashtopolis on a rented GPU cluster; the advisory ties the success to reused or leaked credentials and a legacy SHA-256 password storage (FBI and U.S. Secret Service, 2026-10-06).

What the advisory adds is the lockout. On a compromised firewall the actors create administrator accounts that were not there before and, in some cases, delete existing accounts or change their passwords, so the owners cannot log in and recovery needs steps beyond patching and password resets (FBI and U.S. Secret Service, 2026-10-06; BleepingComputer, 2026-10-07). Cracked credentials are enriched and validated by scripts that filter out honeypots and rank targets by revenue and network structure; with verified credentials the attackers enumerate Active Directory accounts and spray passwords to find privileged users, and the operation packages working VPN configurations and target lists for sale, the role of an initial-access broker (FBI and U.S. Secret Service, 2026-10-06). The advisory says the chain has been an initial entry point for ransomware affiliates, currently INC/Lynx and Payload (FBI and U.S. Secret Service, 2026-10-06); SOCRadar had linked FortiBleed to INC and Lynx in July after reaching both groups' negotiation panels on a server used in the campaign (BleepingComputer, 2026-10-07).

The advisory's measures: restrict external management through trusted hosts, a local-in policy or no internet administration at all; terminate all administrative and VPN sessions and reset all Fortinet VPN and administrator passwords; require phishing-resistant MFA on remote access and administrator accounts; review users, configuration and REST API keys for entries nobody created, removing unknown keys and refreshing the legitimate ones; enforce PBKDF2 for administrator password storage per Fortinet's guidance for FortiOS 7.2.11 and later; and review firewall, VPN, authentication and domain controller logs for lateral movement (FBI and U.S. Secret Service, 2026-10-06). On the FortiGate itself, in analyst judgement, the administrator accounts, passwords and REST API keys the advisory says to review are recorded in the device's configuration and administrator audit log, which is where an unexpected change shows.

Correctionrun 2026-10-11T1307Z-auditactionsbody

The FBI and Secret Service advisory tells operators to review firewall, VPN, authentication and domain controller logs and to check users, configuration and REST API keys for entries nobody created (FBI and U.S. Secret Service, 2026-10-06); it does not name specific Windows event ids or a domain-wide credential rotation, which earlier hunting guidance here attached to the campaign. The mapping of those checks to the FortiGate's own configuration and administrator audit log is a reading of the advisory, not part of it.

incident18 Jun 05:10Zmulti-sourceOpen finding →

2026-08-09 · view entry permalink →

HIGHNATOA2

CERT Polska: a second Polish CHP plant was shut down on 29 December 2025 through the distribution operator's private APN, the first real-world use of that path into an OT network

CERT Polska published a follow-up analysis on 2026-08-08 of the coordinated 29 December 2025 attacks on Poland's energy sector, adding a victim its January report did not carry: a smaller combined heat and power plant supplying heat to roughly 50,000 residents, whose industrial control systems came under attack at about 07:00 that morning (CERT Polska, 2026-08-08). The analysis took more than three months, which is why the case was held back from the initial report published on 30 January 2026 (CERT Polska, 2026-08-08). The head of CERT Polska, Marcin Dudek, presented the case at DEF CON in parallel with publication (CERT Polska, 2026-08-08). The report carries no actor attribution.

The finding that generalises beyond Poland is the access path. Substations that connect renewable generation to the distribution grid commonly carry cellular routers whose SIM cards sit in a private APN, a carrier-operated private mobile network the distribution system operator uses to reach the remote terminal unit at each site, in this case over DNP3.0 (CERT Polska, 2026-08-08). The operator's requirements covered the serial path to the RTU but said nothing about the router's own administrative interface, so the Teltonika RUTX50 at the compromised wind farm sat with its serial link to the RTU on one interface and an Ethernet link into a VLAN behind the already-compromised central firewall on the other (CERT Polska, 2026-08-08). CERT Polska states this is the first instance it knows of in which a private APN was the route into an OT network, made possible by a configuration that let arbitrary devices inside the APN talk to one another, a configuration its surveys found common in Poland and which it believes is widely deployed in other countries (CERT Polska, 2026-08-08).

The chain ran as follows. Every compromised wind-farm substation in the original wave (more than 30 grid connection points) used a FortiGate as both VPN concentrator and firewall, with the VPN interface reachable from the internet and accepting accounts defined on the device itself without multi-factor authentication; the attacker held administrative privileges on the device and likely used them to obtain a VPN account with reach across all network segments (CERT Polska, 2026-08-08). From inside, the attacker logged into the Teltonika router over SSH repeatedly during December 2025 and tunnelled from it into the private APN; how the router password was obtained could not be determined, and whether a flaw in the device was used is likewise unresolved (CERT Polska, 2026-08-08). From 18 December the attacker scanned the APN for VNC and HTTP services and for the S7 and Modbus industrial protocols, and found a WAGO PFC200 controller exposing a web administration interface on its WAN side, reachable from the APN and still on the default credentials for the admin account; SSH was not enabled on that interface by default, and the sequence in the carrier's logs indicates the attacker enabled it through the web interface before tunnelling onward into the heat plant's OT network, to which the controller had connectivity for both the SCADA systems and the segments holding process-control devices (CERT Polska, 2026-08-08).

Reconnaissance inside the plant ran from 18 to 25 December. Repeated attempts to reach the firewall's LAN-side web interface using the account names admin, user and a username belonging to the company that deploys telecontrol systems at renewable sites all failed, and were retried three days later without success (CERT Polska, 2026-08-08). On Sunday 21 December, eight days before the attack, the attacker scanned for S7 on 102/TCP, Modbus on 502/TCP, CODESYS on 11740/TCP and RTSP on 554/TCP alongside RDP, VNC and web services, and in one subnet the scan began at the address of the SCADA system itself, which CERT Polska reads as evidence of earlier reconnaissance having already identified the high-value targets (CERT Polska, 2026-08-08). On Christmas Day the attacker established successful S7 connections to three Siemens PLCs, most plausibly to prepare the destructive step (CERT Polska, 2026-08-08).

On 29 December activity inside the plant network ran from about 05:30 to about 10:10, meaning the operator's recovery work beginning around 07:30 started while the attacker was still present (CERT Polska, 2026-08-08). The first action after tunnelling through the WAGO controller was to open the SCADA server's web interface, then reach an S7-300 over the S7 protocol, repeating the sequence against an S7-1200 and an S7-1500 (CERT Polska, 2026-08-08). According to statements from plant personnel the PLCs were switched to STOP mode and protected with a password blocking both operating-state changes and control-logic modification, shutting down the steam turbine and the process-water treatment system and interrupting cogeneration; prompt operator response held it to a short outage with no interruption to customer heat or electricity supply (CERT Polska, 2026-08-08). The attacker also reconfigured seven Moxa serial device servers and three Moxa switches (factory reset, password changed, addresses moved to unreachable values such as 127.0.0.1) and the timing of the HTTP requests supports a high-confidence assessment that this was automated (CERT Polska, 2026-08-08). Connections to two ABB ACS variable frequency drives were observed with no determinable effect, and attempts against Schneider Electric ATV 6xx drives failed because the attacker targeted 80/TCP while those interfaces listened elsewhere (CERT Polska, 2026-08-08).

Two recovery lessons sit in the anti-forensics. The attacker corrupted the partition table of the WAGO controller used as the gateway, and the operator's own factory reset did not repair it, leaving the device unbootable and its logs unrecoverable; the Teltonika router was factory-reset about thirty minutes after the last plant activity and its address set to 127.0.0.1, and the FortiGate was factory-reset last of all, destroying the logs from the initial entry point (CERT Polska, 2026-08-08). The investigation only recovered router evidence because RutOS versions before 7.07 keep the event database through a factory reset (CERT Polska, 2026-08-08). On the plant side, restoring the Siemens controllers to factory settings and reloading logic backups shortened the outage but deleted the controllers' own logs, and Siemens ProductCERT confirmed they could not be recovered (CERT Polska, 2026-08-08).

Triage: an engineering contractor doing legitimate remote maintenance also logs into a cellular router and reaches PLCs over S7, so neither event alone separates the two. The discriminators here are direction and sequence, the session enters from the APN side of a device whose administrative interface was never meant to face it, port scanning precedes the PLC access by days, and the run-state change is followed within minutes by configuration writes to unrelated serial servers and switches. This plant's operators initially read the shutdown as contractor error during scheduled maintenance and reported it for information only; CERT Polska opened an investigation anyway because it knew of similar events, which is what turned an unexplained failure into a confirmed intrusion (CERT Polska, 2026-08-08).

To the best of our knowledge, the use of a private APN to gain access to the OT network was the first instance of this attack vector being observed in a real-world cyberattack.

The attack was made possible, among other factors, by a misconfiguration that allowed arbitrary devices within the private APN network to communicate with one another.

Surveys conducted among organizations using similar solutions indicated that this configuration was commonly encountered in Poland.

CERT Polska (NASK) 2026-08-08
incident09 Aug 04:42Zsingle-source · national CERTOpen finding →

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