Control32

Hunt Hypothesis

The Control32 rule detects potential adversary behavior involving the execution of suspicious 32-bit control mechanisms that may be used to manipulate or bypass system restrictions. SOC teams should proactively hunt for this behavior in Azure Sentinel to identify early-stage compromises that may evade traditional detection methods.

YARA Rule

rule Control32 {
    meta:
        author = "Jaume Martin"
    condition:
        hash.md5(0, filesize) == "b3dc808fc7cb4492669ec019911ef22a"
}

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
• Source Rule

False Positive Guidance

• Scenario: Legitimate system update via Windows Update
  Filter/Exclusion: process.name != "wuauclt.exe" or process.name != "svchost.exe"

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

• Scenario: Admin task to configure group policy via gpupdate
  Filter/Exclusion: process.name != "gpupdate.exe" or process.name != "services.exe"

• Scenario: Antivirus scan using Bitdefender
  Filter/Exclusion: process.name != "bdagent.exe" or process.name != "bdtray.exe"

• Scenario: Log management tool (e.g., Splunk) collecting logs
  Filter/Exclusion: process.name != "splunkd.exe" or process.name != "splunkforwarder.exe"