Windows Privilege Escalation via Suspicious Process Elevation

This detection identifies suspicious process elevation activity on Windows systems. It focuses on scenarios where a process running with low or medium integrity spawns a new process with higher privileges (high or system integrity) in locations that are considered unusual, such as user directories, temporary folders, or the ProgramData directory. The goal is to identify potential privilege escalation attempts by threat actors. The analytic uses process execution data from Windows process monitoring. Successful privilege escalation can lead to full system compromise and persistent access for the attacker.

Attack Chain

1. An attacker gains initial access to the system with limited privileges, potentially through exploiting a vulnerability or using compromised credentials.
2. The attacker executes a program or script (e.g., PowerShell, cmd.exe) from a non-standard location like the user’s Downloads folder.
3. The initial process runs with a low or medium integrity level.
4. The attacker attempts to elevate privileges by spawning a new process with high or system integrity.
5. The elevated process is launched from a suspicious location such as a user profile directory (e.g., C:\Users\<username>\AppData\Local\Temp) or the C:\ProgramData directory.
6. The elevated process executes malicious code, potentially installing malware or modifying system settings.
7. The attacker achieves higher privileges, allowing them to perform actions that require administrative rights.
8. The attacker gains control over the system and can move laterally to other machines, steal sensitive data, or deploy ransomware.

Impact

Successful privilege escalation allows attackers to gain elevated privileges on the compromised system. This can lead to a full system compromise, enabling attackers to perform unauthorized actions, install malware, steal sensitive data, or move laterally within the network. The detection of this behavior is critical to prevent further damage and maintain system security.

Recommendation

• Enable Sysmon process creation logging (Event ID 1) to capture process execution data and activate the rules below.
• Deploy the Sigma rules in this brief to your SIEM to detect suspicious process elevation attempts and tune for your environment.
• Investigate any alerts generated by the Sigma rules to determine if they are legitimate privilege escalation attempts.
• Review and restrict unnecessary write access to sensitive directories like C:\ProgramData and user profile directories to prevent attackers from launching elevated processes from those locations.
• Implement application control policies to prevent the execution of unauthorized programs.