This detection identifies potential adversary activity involving the unpacking of beta patch files that may contain embedded malicious logic or obfuscated payloads designed to evade static analysis. A proactive hunt is essential in Azure Sentinel to uncover early-stage reconnaissance attempts where attackers leverage legitimate-looking updates to establish a foothold before triggering higher-severity alerts.
rule Upackv032BetaPatchDwing
{
meta:
author="malware-lu"
strings:
$a0 = { BE 88 01 [2] AD 50 ?? AD 91 F3 A5 }
condition:
$a0
}
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 Upackv032BetaPatchDwing detection rule, along with targeted filtering strategies:
Scenario: Scheduled Antivirus Definition Updates via GPO
Upackv032 beta module, which matches the YARA signature due to its specific binary structure and embedded metadata strings.ccmexec.exe (SCCM Agent) or the parent process svchost.exe running under the “System” account. Additionally, restrict the rule trigger to exclude file paths containing \Program Files\Symantec\Symantec Endpoint Protection\Data.Scenario: Deployment of Internal .NET Framework Patches
msiexec installer to unpack and apply a beta patch layer that includes the Upackv032 component as part of the runtime library installation, triggering the rule during the extraction phase.msiexec /i or msiexec /a. Furthermore, filter out alerts originating from the specific service account svc-deployment-admin and file paths located within the temporary deployment directory C:\Temp\AnsibleDeploy.Scenario: Automated Backup of Development Build Artifacts