Adversaries may clear Windows Event Logs to hide the activity of an intrusion. Windows Event Logs are a record of a computer's alerts and notifications. There are three system-defined sources of events: System, Application, and Security, with five event types: Error, Warning, Information, Success Audit, and Failure Audit.
With administrator privileges, the event logs can be cleared with the following utility commands:
These logs may also be cleared through other mechanisms, such as the event viewer GUI or PowerShell. For example, adversaries may use the PowerShell command <code>Remove-EventLog -LogName Security</code> to delete the Security EventLog and after reboot, disable future logging. Note: events may still be generated and logged in the .evtx file between the time the command is run and the reboot.(Citation: disable_win_evt_logging)
Adversaries may also attempt to clear logs by directly deleting the stored log files within C:\Windows\System32\winevt\logs\.
| Capability ID | Capability Description | Mapping Type | ATT&CK ID | ATT&CK Name | Notes |
|---|---|---|---|---|---|
| CVE-2023-36884 | Microsoft Windows Search Remote Code Execution Vulnerability | secondary_impact | T1070.001 | Clear Windows Event Logs |
Comments
This remote code execution vulnerability in Microsoft Office has been exploited by adversarial groups to distribute ransomware. Attackers use specially crafted Microsoft Office documents to bypass security features, enabling remote code execution without user prompts. These documents are typically delivered through phishing techniques, enticing victims to open them. Once opened, the ransomware encrypts files and demands a ransom for decryption, while also removing system backups and leaving a ransom note threatening data loss if recovery is attempted without the provided decryptor key.
The ransomware further erases system logs and may publish stolen data on leak websites, leading to unauthorized access to sensitive information and potential installation of backdoors for further exploitation. Microsoft addressed this vulnerability in their security updates by introducing measures to make file paths unpredictable, thereby mitigating the exploit chain. Despite these updates, additional vulnerabilities in Microsoft Office and Windows were identified. Security solutions offer protection against these exploits, and findings are shared with cybersecurity alliances to enhance collective defense efforts.
This vulnerability has been exploited by the Russian group Storm-0978, also known as RomCom, who craft specially designed Microsoft Office documents related to the Ukrainian World Congress. These documents bypass Microsoft's Mark-of-the-Web (MotW) security feature, enabling remote code execution without security prompts. The adversary used phishing techniques to deliver these documents, enticing victims to open them. Once opened, the ransomware, known as Underground, executes, encrypting files and demanding a ransom for decryption.
The ransomware further removes shadow copies, terminates MS SQL Server services, and leaves a ransom note threatening data loss if recovery is attempted without their decryptor key. It also erases Windows Event logs and publishes stolen victim data on a data leak website, causing unauthorized access to sensitive information and potential installation of backdoors for further exploitation.
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