This detection identifies potential malicious activity where files match the specific signature defined by the aPackv082 YARA rule, indicating the presence of known suspicious artifacts within the environment. A SOC team should proactively hunt for this indicator in Azure Sentinel to validate its relevance across endpoints and prevent low-severity signals from evolving into broader incidents before they escalate.
rule aPackv082
{
meta:
author="malware-lu"
strings:
$a0 = { 1E 06 8C CB BA [2] 03 DA 8D [3] FC 33 F6 33 FF 48 4B 8E C0 8E DB }
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 5 specific false positive scenarios for the aPackv082 detection rule, including suggested filters and exclusions tailored for an enterprise environment:
Scenario: The Microsoft Defender Antivirus (or similar EDR agent) performs a scheduled daily definition update via the MpCmdRun.exe process. This utility often unpacks compressed .cab or .msi files containing new signatures, which triggers the aPackv082 logic due to the presence of embedded archive structures within the update payload.
MpCmdRun.exe (and its child processes) on the specific path C:\Program Files\Windows Defender\MpCmdRun.exe. Alternatively, exclude file paths containing \Microsoft Antimalware\Scan\Definition Updates\ from the rule scope.Scenario: An automated deployment job using System Center Configuration Manager (SCCM) or Microsoft Intune pushes a new application package to endpoints. The client agent extracts .msi installers and associated resource files during the installation phase, creating temporary unpacked directories that match the YARA signature for packed executables.
ccmsetup.exe, AppxPackageInstaller.exe, or smsagenthost.exe. Additionally, create a file path exclusion for the standard SCCM cache directory: C:\Windows\CCMCache\ to prevent alerts on cached installation artifacts.Scenario: The Java Runtime Environment (JRE) launches a scheduled maintenance task that unpacks .jar files or updates internal libraries. Since Java archives are structurally similar to the packed formats detected by aPackv082, legitimate background updates often trigger the rule when the JVM extracts resources into temporary folders.