LY WGKX wwwszleyucom additional

Hunt Hypothesis

This hypothesis targets the presence of the specific YARA signature LY_WGKX_wwwszleyucom_additional, which likely identifies a low-severity web shell or backdoor component associated with the wwwszleyucom infrastructure. Proactively hunting for this indicator in Azure Sentinel allows the SOC team to detect dormant or low-fidelity footholds in web servers before they are leveraged for lateral movement or privilege escalation.

YARA Rule

rule LY_WGKX_wwwszleyucom_additional: PEiD
{
    strings:
        $a = { 4D 5A ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? 52 53 46 58 }
    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

• Web Application Deployment Artifacts: During routine updates to internal web portals (e.g., SharePoint, Confluence, or custom .NET/Java apps), deployment scripts or build pipelines may temporarily leave configuration files, log dumps, or backup archives containing the string wwwszleyucom (often a typo for www.szleyu.com or a specific vendor domain) in application directories like C:\InetPub\wwwroot or /var/www/html.

  • Filter/Exclusion: Exclude files located in standard web root directories (C:\InetPub\wwwroot\, /var/www/html/, C:\Program Files\Apache Software Foundation\) and files with extensions like .log, .bak, or .tmp created within the last 24 hours.

• Vendor-Specific Support Tools: Third-party support utilities or diagnostic agents from vendors using the domain szleyu.com (or similar typos) may write temporary state files, license checks, or telemetry caches to C:\ProgramData\ or C:\Users\<Admin>\AppData\Local\. These files often contain hardcoded URLs for update checks or support ticket submission.

  • Filter/Exclusion: Exclude files owned by known vendor service accounts (e.g., svc_vendor_support) and located in C:\ProgramData\<VendorName>\ or C:\Users\<Admin>\AppData\Local\<VendorName>\ where the file name matches known vendor tool patterns (e.g., diag_*.dat, license_check.tmp).

• Scheduled Backup and Cleanup Jobs: Enterprise backup solutions (e.g., Veeam, Commvault, or custom PowerShell scripts) may create temporary staging areas for backup catalogs or metadata files. If the backup catalog includes a web application with the URL wwwszleyucom in its metadata or if a cleanup script leaves behind