Zimbra Collaboration

Adversaries may scan victims for vulnerabilities that can be used during targeting. Vulnerability scans typically check if the configuration of a target host/application (ex: software and version) potentially aligns with the target of a specific exploit the adversary may seek to use.

Evidence: 2026-08-20/cve-2026-73570-zimbra-snmp-command-injection-exploited · ATT&CK page ↗

Adversaries may upload, install, or otherwise set up capabilities that can be used during targeting. To support their operations, an adversary may need to take capabilities they developed (Develop Capabilities) or obtained (Obtain Capabilities) and stage them on infrastructure under their control. These capabilities may be staged on infrastructure that was previously purchased/rented by the adversary (Acquire Infrastructure) or was otherwise compromised by them (Compromise Infrastructure). Capabilities may also be staged on web services, such as GitHub or Pastebin, or on Platform-as-a-Service (PaaS) offerings that enable users to easily provision applications.

Evidence: 2026-07-24/laundry-bear-zimbra-zero-click-cve-2025-66376 · ATT&CK page ↗

Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network. The weakness in the system can be a software bug, a temporary glitch, or a misconfiguration.

Evidence: 2026-08-23/uat-10147-agentic-ai-exploitation-oob-confirmation · 2026-08-20/cve-2026-73570-zimbra-snmp-command-injection-exploited · 2026-07-25/ta458-roundpress-webmail-zero-days-sogo-cve-2026-8496 · 2026-07-22/zimbra-10-1-20-snmp-command-injection-rce-plus-stored-xss · ATT&CK page ↗

Adversaries may send phishing messages to gain access to victim systems. All forms of phishing are electronically delivered social engineering. Phishing can be targeted, known as spearphishing. In spearphishing, a specific individual, company, or industry will be targeted by the adversary. More generally, adversaries can conduct non-targeted phishing, such as in mass malware spam campaigns.

Evidence: 2026-07-25/ta458-roundpress-webmail-zero-days-sogo-cve-2026-8496 · 2026-07-24/laundry-bear-zimbra-zero-click-cve-2025-66376 · ATT&CK page ↗

Adversaries may abuse the <code>cron</code> utility to perform task scheduling for initial or recurring execution of malicious code. The <code>cron</code> utility is a time-based job scheduler for Unix-like operating systems. The <code> crontab</code> file contains the schedule of cron entries to be run and the specified times for execution. Any <code>crontab</code> files are stored in operating system-specific file paths.

Evidence: 2026-08-20/cve-2026-73570-zimbra-snmp-command-injection-exploited · ATT&CK page ↗

Adversaries may abuse the Windows Task Scheduler to perform task scheduling for initial or recurring execution of malicious code. There are multiple ways to access the Task Scheduler in Windows. The schtasks utility can be run directly on the command line, or the Task Scheduler can be opened through the GUI within the Administrator Tools section of the Control Panel. In some cases, adversaries have used a .NET wrapper for the Windows Task Scheduler, and alternatively, adversaries have used the Windows netapi32 library and Windows Management Instrumentation (WMI) to create a scheduled task. Adversaries may also utilize the Powershell Cmdlet `Invoke-CimMethod`, which leverages WMI class `PS_ScheduledTask` to create a scheduled task via an XML path.

Evidence: 2026-08-23/uat-10147-agentic-ai-exploitation-oob-confirmation · ATT&CK page ↗

Adversaries may abuse command and script interpreters to execute commands, scripts, or binaries. These interfaces and languages provide ways of interacting with computer systems and are a common feature across many different platforms. Most systems come with some built-in command-line interface and scripting capabilities, for example, macOS and Linux distributions include some flavor of Unix Shell while Windows installations include the Windows Command Shell and PowerShell.

Evidence: 2026-07-22/zimbra-10-1-20-snmp-command-injection-rce-plus-stored-xss · ATT&CK page ↗

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: 2026-08-20/cve-2026-73570-zimbra-snmp-command-injection-exploited · ATT&CK page ↗

Adversaries may abuse various implementations of JavaScript for execution. JavaScript (JS) is a platform-independent scripting language (compiled just-in-time at runtime) commonly associated with scripts in webpages, though JS can be executed in runtime environments outside the browser.

Evidence: 2026-07-24/laundry-bear-zimbra-zero-click-cve-2025-66376 · 2026-07-10/zimbra-classic-web-client-code-exec-ncsc-ch · ATT&CK page ↗

Adversaries may exploit software vulnerabilities in client applications to execute code. Vulnerabilities can exist in software due to unsecure coding practices that can lead to unanticipated behavior. Adversaries can take advantage of certain vulnerabilities through targeted exploitation for the purpose of arbitrary code execution. Oftentimes the most valuable exploits to an offensive toolkit are those that can be used to obtain code execution on a remote system because they can be used to gain access to that system. Users will expect to see files related to the applications they commonly used to do work, so they are a useful target for exploit research and development because of their high utility.

Evidence: 2026-07-25/ta458-roundpress-webmail-zero-days-sogo-cve-2026-8496 · 2026-07-24/laundry-bear-zimbra-zero-click-cve-2025-66376 · 2026-07-10/zimbra-classic-web-client-code-exec-ncsc-ch · ATT&CK page ↗

Adversaries may abuse the <code>cron</code> utility to perform task scheduling for initial or recurring execution of malicious code. The <code>cron</code> utility is a time-based job scheduler for Unix-like operating systems. The <code> crontab</code> file contains the schedule of cron entries to be run and the specified times for execution. Any <code>crontab</code> files are stored in operating system-specific file paths.

Evidence: 2026-08-20/cve-2026-73570-zimbra-snmp-command-injection-exploited · ATT&CK page ↗

Adversaries may abuse the Windows Task Scheduler to perform task scheduling for initial or recurring execution of malicious code. There are multiple ways to access the Task Scheduler in Windows. The schtasks utility can be run directly on the command line, or the Task Scheduler can be opened through the GUI within the Administrator Tools section of the Control Panel. In some cases, adversaries have used a .NET wrapper for the Windows Task Scheduler, and alternatively, adversaries have used the Windows netapi32 library and Windows Management Instrumentation (WMI) to create a scheduled task. Adversaries may also utilize the Powershell Cmdlet `Invoke-CimMethod`, which leverages WMI class `PS_ScheduledTask` to create a scheduled task via an XML path.

Evidence: 2026-08-23/uat-10147-agentic-ai-exploitation-oob-confirmation · ATT&CK page ↗

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: 2026-07-24/laundry-bear-zimbra-zero-click-cve-2025-66376 · ATT&CK page ↗

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: 2026-08-23/uat-10147-agentic-ai-exploitation-oob-confirmation · ATT&CK page ↗

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: 2026-08-23/uat-10147-agentic-ai-exploitation-oob-confirmation · 2026-08-20/cve-2026-73570-zimbra-snmp-command-injection-exploited · 2026-07-25/ta458-roundpress-webmail-zero-days-sogo-cve-2026-8496 · ATT&CK page ↗

Adversaries may create or modify systemd services to repeatedly execute malicious payloads as part of persistence. Systemd is a system and service manager commonly used for managing background daemon processes (also known as services) and other system resources. Systemd is the default initialization (init) system on many Linux distributions replacing legacy init systems, including SysVinit and Upstart, while remaining backwards compatible.

Evidence: 2026-08-20/cve-2026-73570-zimbra-snmp-command-injection-exploited · ATT&CK page ↗

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

Evidence: 2026-07-24/laundry-bear-zimbra-zero-click-cve-2025-66376 · ATT&CK page ↗

Adversaries may abuse the <code>cron</code> utility to perform task scheduling for initial or recurring execution of malicious code. The <code>cron</code> utility is a time-based job scheduler for Unix-like operating systems. The <code> crontab</code> file contains the schedule of cron entries to be run and the specified times for execution. Any <code>crontab</code> files are stored in operating system-specific file paths.

Evidence: 2026-08-20/cve-2026-73570-zimbra-snmp-command-injection-exploited · ATT&CK page ↗

Adversaries may abuse the Windows Task Scheduler to perform task scheduling for initial or recurring execution of malicious code. There are multiple ways to access the Task Scheduler in Windows. The schtasks utility can be run directly on the command line, or the Task Scheduler can be opened through the GUI within the Administrator Tools section of the Control Panel. In some cases, adversaries have used a .NET wrapper for the Windows Task Scheduler, and alternatively, adversaries have used the Windows netapi32 library and Windows Management Instrumentation (WMI) to create a scheduled task. Adversaries may also utilize the Powershell Cmdlet `Invoke-CimMethod`, which leverages WMI class `PS_ScheduledTask` to create a scheduled task via an XML path.

Evidence: 2026-08-23/uat-10147-agentic-ai-exploitation-oob-confirmation · ATT&CK page ↗

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: 2026-08-23/uat-10147-agentic-ai-exploitation-oob-confirmation · ATT&CK page ↗

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: 2026-07-24/laundry-bear-zimbra-zero-click-cve-2025-66376 · ATT&CK page ↗

Adversaries may create or modify systemd services to repeatedly execute malicious payloads as part of persistence. Systemd is a system and service manager commonly used for managing background daemon processes (also known as services) and other system resources. Systemd is the default initialization (init) system on many Linux distributions replacing legacy init systems, including SysVinit and Upstart, while remaining backwards compatible.

Evidence: 2026-08-20/cve-2026-73570-zimbra-snmp-command-injection-exploited · ATT&CK page ↗

Adversaries may perform sudo caching and/or use the sudoers file to elevate privileges. Adversaries may do this to execute commands as other users or spawn processes with higher privileges.

Evidence: 2026-08-20/cve-2026-73570-zimbra-snmp-command-injection-exploited · ATT&CK page ↗

Adversaries may attempt to make an executable or file difficult to discover or analyze by encrypting, encoding, or otherwise obfuscating its contents on the system or in transit. This is common behavior that can be used across different platforms and the network to evade defenses.

Evidence: 2026-08-23/uat-10147-agentic-ai-exploitation-oob-confirmation · ATT&CK page ↗

Adversaries may smuggle data and files past content filters by hiding malicious payloads inside of seemingly benign SVG files. SVGs, or Scalable Vector Graphics, are vector-based image files constructed using XML. As such, they can legitimately include `<script>` tags that enable adversaries to include malicious JavaScript payloads. However, SVGs may appear less suspicious to users than other types of executable files, as they are often treated as image files.

Evidence: 2026-07-24/laundry-bear-zimbra-zero-click-cve-2025-66376 · ATT&CK page ↗

Adversaries may match or approximate the name or location of legitimate files, Registry keys, or other resources when naming/placing them. This is done for the sake of evading defenses and observation.

Evidence: 2026-08-20/cve-2026-73570-zimbra-snmp-command-injection-exploited · ATT&CK page ↗

Adversaries may modify file time attributes to hide new files or changes to existing files. Timestomping is a technique that modifies the timestamps of a file (the modify, access, create, and change times), often to mimic files that are in the same folder and blend malicious files with legitimate files.

Evidence: 2026-08-20/cve-2026-73570-zimbra-snmp-command-injection-exploited · ATT&CK page ↗

Adversaries may reflectively load code into a process in order to conceal the execution of malicious payloads. Reflective loading involves allocating then executing payloads directly within the memory of the process, vice creating a thread or process backed by a file path on disk (e.g., Shared Modules).

Evidence: 2026-08-20/cve-2026-73570-zimbra-snmp-command-injection-exploited · ATT&CK page ↗

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

Evidence: 2026-07-24/laundry-bear-zimbra-zero-click-cve-2025-66376 · ATT&CK page ↗

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: 2026-08-23/uat-10147-agentic-ai-exploitation-oob-confirmation · ATT&CK page ↗

Adversaries may use brute force techniques to gain access to accounts when passwords are unknown or when password hashes are obtained. Without knowledge of the password for an account or set of accounts, an adversary may systematically guess the password using a repetitive or iterative mechanism. Brute forcing passwords can take place via interaction with a service that will check the validity of those credentials or offline against previously acquired credential data, such as password hashes.

Evidence: 2026-08-20/cve-2026-73570-zimbra-snmp-command-injection-exploited · ATT&CK page ↗

An adversary may steal web application or service session cookies and use them to gain access to web applications or Internet services as an authenticated user without needing credentials. Web applications and services often use session cookies as an authentication token after a user has authenticated to a website.

Evidence: 2026-07-25/ta458-roundpress-webmail-zero-days-sogo-cve-2026-8496 · 2026-07-24/laundry-bear-zimbra-zero-click-cve-2025-66376 · 2026-07-10/zimbra-classic-web-client-code-exec-ncsc-ch · ATT&CK page ↗

Adversaries may search local file systems and remote file shares for files containing insecurely stored credentials. These can be files created by users to store their own credentials, shared credential stores for a group of individuals, configuration files containing passwords for a system or service, or source code/binary files containing embedded passwords.

Evidence: 2026-08-20/cve-2026-73570-zimbra-snmp-command-injection-exploited · ATT&CK page ↗

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

Evidence: 2026-07-24/laundry-bear-zimbra-zero-click-cve-2025-66376 · ATT&CK page ↗

Adversaries may attempt to get a listing of email addresses and accounts. Adversaries may try to dump Exchange address lists such as global address lists (GALs).

Evidence: 2026-07-24/laundry-bear-zimbra-zero-click-cve-2025-66376 · ATT&CK page ↗

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: 2026-08-20/cve-2026-73570-zimbra-snmp-command-injection-exploited · ATT&CK page ↗

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: 2026-08-20/cve-2026-73570-zimbra-snmp-command-injection-exploited · ATT&CK page ↗

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: 2026-08-20/cve-2026-73570-zimbra-snmp-command-injection-exploited · ATT&CK page ↗

Adversaries may target user email on local systems to collect sensitive information. Files containing email data can be acquired from a user’s local system, such as Outlook storage or cache files.

Evidence: 2026-08-20/cve-2026-73570-zimbra-snmp-command-injection-exploited · ATT&CK page ↗

Adversaries may target an Exchange server, Office 365, or Google Workspace to collect sensitive information. Adversaries may leverage a user's credentials and interact directly with the Exchange server to acquire information from within a network. Adversaries may also access externally facing Exchange services, Office 365, or Google Workspace to access email using credentials or access tokens. Tools such as MailSniper can be used to automate searches for specific keywords.

Evidence: 2026-07-25/ta458-roundpress-webmail-zero-days-sogo-cve-2026-8496 · 2026-07-24/laundry-bear-zimbra-zero-click-cve-2025-66376 · ATT&CK page ↗

Adversaries may setup email forwarding rules to collect sensitive information. Adversaries may abuse email forwarding rules to monitor the activities of a victim, steal information, and further gain intelligence on the victim or the victim’s organization to use as part of further exploits or operations. Furthermore, email forwarding rules can allow adversaries to maintain persistent access to victim's emails even after compromised credentials are reset by administrators. Most email clients allow users to create inbox rules for various email functions, including forwarding to a different recipient. These rules may be created through a local email application, a web interface, or by command-line interface. Messages can be forwarded to internal or external recipients, and there are no restrictions limiting the extent of this rule. Administrators may also create forwarding rules for user accounts with the same considerations and outcomes.

Evidence: 2026-07-22/zimbra-10-1-20-snmp-command-injection-rce-plus-stored-xss · ATT&CK page ↗

Adversaries may use utilities to compress and/or encrypt collected data prior to exfiltration. Many utilities include functionalities to compress, encrypt, or otherwise package data into a format that is easier/more secure to transport.

Evidence: 2026-08-20/cve-2026-73570-zimbra-snmp-command-injection-exploited · ATT&CK page ↗

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: 2026-08-23/uat-10147-agentic-ai-exploitation-oob-confirmation · 2026-08-20/cve-2026-73570-zimbra-snmp-command-injection-exploited · ATT&CK page ↗

Adversaries may communicate using the Domain Name System (DNS) application layer protocol 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: 2026-07-24/laundry-bear-zimbra-zero-click-cve-2025-66376 · ATT&CK page ↗

Adversaries may use a connection proxy to direct network traffic between systems or act as an intermediary for network communications to a command and control server to avoid direct connections to their infrastructure. Many tools exist that enable traffic redirection through proxies or port redirection, including HTRAN, ZXProxy, and ZXPortMap. Adversaries use these types of proxies to manage command and control communications, reduce the number of simultaneous outbound network connections, provide resiliency in the face of connection loss, or to ride over existing trusted communications paths between victims to avoid suspicion. Adversaries may chain together multiple proxies to further disguise the source of malicious traffic.

Evidence: 2026-08-20/cve-2026-73570-zimbra-snmp-command-injection-exploited · ATT&CK page ↗

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: 2026-08-23/uat-10147-agentic-ai-exploitation-oob-confirmation · 2026-08-20/cve-2026-73570-zimbra-snmp-command-injection-exploited · ATT&CK page ↗

Adversaries may steal data by exfiltrating it over an un-encrypted network protocol other than that of the existing command and control channel. The data may also be sent to an alternate network location from the main command and control server.

Evidence: 2026-07-24/laundry-bear-zimbra-zero-click-cve-2025-66376 · ATT&CK page ↗

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: 2026-08-20/cve-2026-73570-zimbra-snmp-command-injection-exploited · ATT&CK page ↗

Adversaries may leverage the compute resources of co-opted systems to complete resource-intensive tasks, which may impact system and/or hosted service availability.

Evidence: 2026-08-20/cve-2026-73570-zimbra-snmp-command-injection-exploited · ATT&CK page ↗

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: 2026-08-20/cve-2026-73570-zimbra-snmp-command-injection-exploited · ATT&CK page ↗