Checks for the presence of known debug tools

Hunt Hypothesis

The presence of known debug tools may indicate an adversary attempting to analyze or manipulate system behavior during an initial compromise. SOC teams should proactively hunt for this behavior in Azure Sentinel to identify potential early-stage reconnaissance or persistence activities.

YARA Rule

rule anti_dbgtools {
    meta:
        author = "x0r"
        description = "Checks for the presence of known debug tools"
	version = "0.1"
    strings:
        $f1 = "procexp.exe" nocase
        $f2 = "procmon.exe" nocase
        $f3 = "processmonitor.exe" nocase
        $f4 = "wireshark.exe" nocase
        $f5 = "fiddler.exe" nocase
        $f6 = "windbg.exe" nocase
        $f7 = "ollydbg.exe" nocase
        $f8 = "winhex.exe" nocase
        $f9 = "processhacker.exe" nocase
        $f10 = "hiew32.exe" nocase
        $c11 = "\\\\.\\NTICE"
        $c12 = "\\\\.\\SICE"
        $c13 = "\\\\.\\Syser"
        $c14 = "\\\\.\\SyserBoot"
        $c15 = "\\\\.\\SyserDbgMsg"
    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 15 string patterns in its detection logic.

• Source Rule

False Positive Guidance

• Scenario: System administrators use Process Monitor (ProcMon) to troubleshoot application performance issues.
  Filter/Exclusion: Exclude processes with ProcessMonitor.exe or ProcMon.exe in the process name.

• Scenario: Developers use GDB (GNU Debugger) for local debugging of C/C++ applications during development.
  Filter/Exclusion: Exclude processes with gdb.exe or processes running in a development environment (e.g., IDE or Visual Studio).

• Scenario: A scheduled job runs Wireshark to capture network traffic for analysis.
  Filter/Exclusion: Exclude processes launched via scheduled tasks with Wireshark.exe or tshark.exe in the command line.

• Scenario: Windows Debuggers like WinDbg are used for kernel-level troubleshooting during incident response.
  Filter/Exclusion: Exclude processes with windbg.exe or processes initiated by the Windows Debugger service.

• Scenario: Remote Desktop Services (RDS) or Terminal Services use debug tools for session monitoring or logging.
  Filter/Exclusion: Exclude processes associated with mstsc.exe, tsclient.exe, or running under the Remote Desktop Services user context.