md5 3ccdd51fe616c08daafd601589182d38

Hunt Hypothesis

The detection rule identifies potential malicious activity associated with a specific MD5 hash, which may indicate the presence of unknown or low-severity threats. SOC teams should proactively hunt for this behavior in Azure Sentinel to uncover hidden or evasive threats that may not be captured by traditional detection methods.

YARA Rule

rule md5_3ccdd51fe616c08daafd601589182d38 {
    strings: $ = "eval(xxtea_decrypt"
    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
• Source Rule

False Positive Guidance

• Scenario: A system update or patching tool (e.g., Windows Update, SCCM) downloads a legitimate file with the MD5 hash 3ccdd51fe616c08daafd601589182d38 as part of its update process.
  Filter/Exclusion: Check the file path against known update directories (e.g., C:\Windows\Temp, C:\Windows\SoftwareDistribution, or registry keys like HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\WindowsUpdate).

• Scenario: A backup or synchronization tool (e.g., Veeam, rsync, or Azure Backup) transfers a file with the same MD5 hash during routine operations.
  Filter/Exclusion: Filter based on file paths related to backup directories (e.g., C:\Backup, D:\Synced_Files) or check the process name against known backup tools.

• Scenario: A scheduled administrative task (e.g., via Task Scheduler or PowerShell) runs a script or executable that legitimately uses the hash 3ccdd51fe616c08daafd601589182d38 for a known, benign purpose.
  Filter/Exclusion: Exclude processes running under known administrative tasks or check the command line arguments for expected script names or parameters.

• Scenario: A legitimate software installation or deployment tool (e.g., Ansible, Puppet, or Chef) uses a file with the MD5 hash during package distribution.
  Filter/Exclusion: Filter based on file paths in known deployment directories (e.g., C:\ProgramData\DeploymentTools, C:\Temp\InstallFiles) or check the source of the file against trusted repositories.

• Scenario: A user or admin manually runs a script or executable (e.g., `powers