cxpid code features

Hunt Hypothesis

The cxpid code features rule detects potential adversary behavior involving the use of obfuscated or suspicious code execution patterns that may indicate malicious activity. SOC teams should proactively hunt for this behavior in Azure Sentinel to identify and mitigate early-stage threats that could evade traditional detection methods.

YARA Rule

rule cxpidCode
{
    meta:
        description = "cxpid code features"
        author = "Seth Hardy"
        last_modified = "2014-06-23"
    
    strings:
        $entryjunk = { 55 8B EC B9 38 04 00 00 6A 00 6A 00 49 75 F9 }
    
    condition:
        any of them
}

Deployment Notes

This YARA rule can be deployed in the following contexts:

• Microsoft Defender for Endpoint — Custom indicators / advanced hunting
• Email Gateway — Attachment scanning
• File Share Monitoring — Periodic scanning of shared drives
• YARA CLI — Manual threat hunting on endpoints

This rule contains 1 string patterns in its detection logic.

• Source Rule

False Positive Guidance

• Scenario: Scheduled system backup using Veeam Backup & Replication
  Filter/Exclusion: process.parent_process_name != "veeambackup" or process.name != "vmbackup.exe"

• Scenario: Regular log file rotation performed by Logrotate on Linux servers
  Filter/Exclusion: process.name != "logrotate" or process.command_line contains "rotate"

• Scenario: Admin task to update endpoint protection definitions via Microsoft Defender for Endpoint
  Filter/Exclusion: process.name != "mpsvc.exe" or process.command_line contains "update"

• Scenario: Automated CI/CD pipeline deployment using Jenkins executing a script
  Filter/Exclusion: process.parent_process_name != "jenkins.exe" or process.command_line contains "jenkins-agent"

• Scenario: Database maintenance task using SQL Server Agent job to clean up temporary files
  Filter/Exclusion: process.name != "sqlservr.exe" or process.command_line contains "sqlagent -d"