KBySV022shoooo

Hunt Hypothesis

This YARA rule targets specific binary patterns or code artifacts that may indicate the presence of a low-severity threat or known malware variant within Azure workloads. Proactively hunting for these signatures allows the SOC team to identify dormant or stealthy compromises before they escalate into more impactful incidents.

YARA Rule

rule KBySV022shoooo
{
      meta:
		author="malware-lu"
strings:
		$a0 = { 68 [4] E8 01 00 00 00 C3 C3 11 55 07 8B EC B8 [4] E8 }

condition:
		$a0 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: A developer or DevOps engineer runs a local build script or CI/CD pipeline agent (e.g., Jenkins, GitLab Runner, or Azure DevOps Agent) that compiles source code containing the specific string pattern or binary signature defined by KBySV022shoooo.

  • Filter/Exclusion: Exclude processes where the parent process is a known build tool (e.g., msbuild.exe, dotnet.exe, npm.exe, python.exe executing a build script) or where the file path resides in standard build directories (e.g., \builds\, \artifacts\, \node_modules\).

• Scenario: An automated backup or archival job (e.g., Veeam, Commvault, or Windows Server Backup) scans or restores a large number of files, including legacy applications or data archives that contain the YARA-matched signature as part of their embedded metadata or code.

  • Filter/Exclusion: Exclude events where the initiating process is a known backup agent (e.g., veeam.exe, commvault.exe, wbadmin.exe) or where the file extension matches common archive formats (.zip, .tar, .7z, .bak).

• Scenario: A software vendor’s auto-updater (e.g., Adobe Creative Cloud, JetBrains Toolbox, or Visual Studio Installer) downloads and installs a new version of an application. The newly installed executable or DLL matches the YARA rule because it is a known, signed component of the legitimate software package.

  • Filter/Exclusion: Exclude files that are digitally signed by a trusted vendor certificate (e.g., Adobe Inc., JetBrains s.r.o., Microsoft Corporation) and where the file path is within the vendor’s standard installation directory (e.g., C:\Program Files\Adobe\, `C:\Users\