Indicators in Logs Suggesting a Privilege Escalation Attack
Privilege escalation attacks involve exploiting vulnerabilities or abusing configurations to gain elevated access. Detecting such activity requires monitoring specific events, analyzing suspicious behavior, and correlating log data.
1. Unusual Account Activity
What to Look For:
Behavioral Anomalies: Low-privileged accounts suddenly performing high-privilege actions, such as:
Accessing sensitive files.
Installing or modifying software.
Making administrative changes.
Key Event IDs:
4672: Special privileges assigned to a new logon.
4624: Successful logons, especially Type 2 (interactive) or Type 10 (remote interactive) sessions.
Red Flags: Accounts accessing resources or performing tasks outside their typical role or authorization level.
2. Examine Security Logs for Token Manipulation
What to Look For:
Token Manipulation Techniques: Logs showing attempts to impersonate other users or elevate privileges using tools like Mimikatz or through Windows token manipulation.
Key Event IDs:
4673: A privileged service was called, indicating attempts to access sensitive functions.
4689: Process termination logs that might reveal attempts to hide tracks post-escalation.
Red Flags: Repetitive access to high-privilege functions or processes by unusual accounts.
3. Analyze Scheduled Tasks and Services
What to Look For:
Unauthorized Task Creation: Attackers may create scheduled tasks or install services to execute malicious code with elevated privileges.
Key Event IDs:
4697: Logs the creation of new services.
4702: Modifications to scheduled tasks.
Red Flags: New tasks or services appearing on critical systems or configured by non-administrative accounts.
4. Audit Process Creation Logs
What to Look For:
High-Integrity Processes: Investigate processes like
cmd.exe,powershell.exe, or custom scripts running with elevated privileges.Key Event IDs:
4688: Captures process creation, including the command line, user, and integrity level.
Red Flags:
Processes initiated by unexpected users or containing suspicious parameters such as -ExecutionPolicy Bypass or encoded commands.
5. Look for File Permission Changes
What to Look For:
Changes in File or Directory Permissions: Logs indicating unauthorized changes to file or directory permissions, potentially allowing non-privileged users to execute files with elevated rights.
Key Indicators:
Audit file system logs for
SetACLor similar permission modification commands.Unexplained changes to permissions on sensitive directories or executables.
Red Flags: Changes to permissions on critical files or directories without a legitimate justification.
6. Network Anomalies
What to Look For:
Lateral Movement Attempts: Privilege escalation is often followed by lateral movement to gain control of critical systems. Monitor for unusual SMB, RDP, or WMI traffic, especially between systems that don’t typically communicate.
Log Correlation: Link logs from endpoints with network traffic to identify connections initiated after privilege escalation.
Red Flags: Unexplained internal connections or resource access following elevated privilege actions.
7. Immediate Response
What to Do:
Revoke Access: Disable or suspend the compromised account to prevent further misuse.
Isolate Affected Systems: Disconnect systems where suspicious privilege escalation activity occurred to contain the threat.
Investigate Escalation Method: Analyze logs to determine the exact mechanism used to escalate privileges and identify any additional compromised accounts or systems.
Post-Incident Steps:
Conduct a forensic analysis to trace the full attack path and identify vulnerabilities.
Patch exploited systems and review privilege configurations to prevent recurrence.
Implement stricter monitoring and access control policies.
Conclusion
By focusing on specific Event IDs, behavioral anomalies, and log correlations, security teams can detect and respond to privilege escalation attacks effectively. Swift action is critical to mitigate the potential damage from an attacker gaining elevated access within a network.
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