ExeSafeguard v10 simonzh h additional

Hunt Hypothesis

This YARA rule targets specific executable file characteristics associated with the “simonzh” signature, potentially indicating the presence of a known or emerging malware strain or a tool used for post-exploitation activities. Proactively hunting for these indicators in Azure Sentinel allows the SOC to identify compromised endpoints or dropped payloads early, reducing the dwell time of low-severity threats that might otherwise evade standard behavioral detections.

YARA Rule

rule ExeSafeguard_v10_simonzh_h_additional: PEiD
{
    strings:
        $a = { C0 5D EB 4E EB 47 DF 69 4E 58 DF 59 74 F3 EB 01 DF 75 EE 9A 59 9C 81 C1 E2 FF FF FF EB 01 DF 9D FF E1 E8 51 E8 EB FF FF FF DF 22 3F 9A C0 81 ED 19 18 40 00 EB 48 EB 47 DF 69 4E 58 DF 59 79 EE EB 01 DF 78 E9 DF 59 9C 81 C1 E5 FF FF FF 9D FF E1 EB 51 E8 EE FF FF FF DF BA A3 22 3F 9A C0 60 EB 4D EB 47 DF 69 4E 58 DF 59 79 F3 EB 01 DF 78 EE DF 59 9C 81 C1 E5 FF FF FF 9D FF E1 EB 51 E8 EE FF FF FF E8 BA A3 22 3F 9A C0 8D B5 EE 19 40 00 EB 47 EB 47 DF 69 4E 58 DF 59 7A EE EB 01 DF 7B E9 DF 59 9C 81 C1 E5 FF FF FF 9D FF E1 EB 51 E8 EE FF FF FF DF 22 3F 9A C0 8B FE EB 4C EB 47 DF 69 4E 58 DF 59 74 F2 EB 01 DF 75 ED 0F 59 9C 81 C1 E5 FF FF FF 9D FF E1 EB 51 E8 EE FF FF FF E8 BA A3 22 3F 9A C0 B9 2B CB 00 00 EB 4B EB 47 DF 69 4E 58 DF 59 78 EF }
    condition:
        $a at pe.entry_point

}

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: Execution of the ExeSafeguard utility by a DevOps engineer during a routine CI/CD pipeline deployment to verify binary integrity or apply specific safeguarding patches to application executables.
  • Filter/Exclusion: Exclude if the parent process is a known build agent (e.g., jenkins.exe, agent.exe, vstsagent.exe) or if the command line arguments contain specific flags like /verify or /patch associated with the deployment script.
• Scenario: A scheduled maintenance task running ExeSafeguard via Task Scheduler to periodically scan and protect critical service binaries (e.g., sqlservr.exe, iisexpress.exe) against tampering.
  • Filter/Exclusion: Exclude if the parent process is svchost.exe (specifically the Task Scheduler service) and the working directory matches the standard application installation path (e.g., C:\Program Files\... or C:\Windows\System32\...).
• Scenario: An IT administrator manually running ExeSafeguard from a command prompt to debug why a specific application binary is being blocked by the safeguard policy, often invoked with verbose logging flags.
  • Filter/Exclusion: Exclude if the process is launched from a terminal emulator (e.g., cmd.exe, powershell.exe, wt.exe) and the user account belongs to a privileged group (e.g., Domain Admins, IT_Support) with the command line containing debug flags like -v or --log.
• Scenario: A third-party endpoint protection agent or custom security tooling using ExeSafeguard as a helper binary to perform hash verification or digital signature checks on newly downloaded or updated executables.
  • Filter/Exclusion: Exclude if the parent process