This detection identifies specific file artifacts matching the XCRv012 YARA signature to uncover potential early-stage malware or suspicious executables that may evade standard heuristic scans. Proactively hunting for this indicator in Azure Sentinel allows the SOC team to validate low-severity alerts against actual threat intelligence, ensuring that subtle signs of compromise are not overlooked before they escalate into significant incidents.
rule XCRv012
{
meta:
author="malware-lu"
strings:
$a0 = { 60 9C E8 [4] 8B DD 5D 81 ED [4] 89 9D }
condition:
$a0 at pe.entry_point
}
This YARA rule can be deployed in the following contexts:
This rule contains 1 string patterns in its detection logic.
Here are 4 specific false positive scenarios for the XCRv012 detection rule, including targeted filters and exclusions suitable for an enterprise environment:
Antivirus Scheduled Scans on Shared Drives
\\FileServer\Shared) during off-hours. The YARA rule may flag the high-volume file I/O and signature scanning processes as anomalous execution patterns, triggering XCRv012 when legitimate scan engines access thousands of files simultaneously.C:\Program Files\CrowdStrike\*\csagent.exe or C:\ProgramData\Microsoft\Windows Defender\Platform\<version>\MpCmdRun.exe where the parent process is a scheduled task (Task Scheduler) and the target path contains \Shared.Software Deployment via Configuration Management Tools
ccmsetup.exe (SCCM) or java.exe (Jenkins/Ansible controllers) where the command line arguments contain keywords like /install, /deploy, or -Dconfig.Database Backup and Maintenance Jobs