This detection identifies potential unauthorized file replication activities by monitoring for specific behavioral patterns defined in the CopyControlv303 YARA signature, which often indicate early-stage data staging or lateral movement by an adversary. Proactively hunting for this low-severity signal within Azure Sentinel is essential to uncover subtle exfiltration attempts that may be missed by high-volume alerting systems before they escalate into significant data breaches.
rule CopyControlv303
{
meta:
author="malware-lu"
strings:
$a0 = { CC 90 90 EB 0B 01 50 51 52 53 54 61 33 61 2D 35 CA D1 07 52 D1 A1 3C }
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 CopyControlv303 detection rule, including targeted filters and exclusions tailored for an enterprise environment:
Scenario: Automated Backup Execution by Veeam or Commvault
Veeam.Backup.Service.exe or commvault.cmd) frequently copy large volumes of data from source directories to backup repositories, triggering the rule’s file-copy logic.\\BackupServer\Repos\*). Add a whitelist for specific Service Accounts used by these tools (e.g., DOMAIN\VeeamSvc, DOMAIN\CmService).Scenario: Scheduled Deployment via Microsoft SCCM or Intune
ccmexec.exe) or Intune Management Extension copies application binaries and configuration files to client machines. This often involves copying executables from a distribution point to the local C:\Windows\CCM directory.ccmsetup.exe, Microsoft.IntuneManagementExtension.exe, or wsmantrc.exe when the source path is the network share used by the management point (e.g., \\SCCM-Site\SoftwareDistribution\*).Scenario: Antivirus Real-Time Scanning and Quarantine
csagent.exe) or Microsoft Defender (MsMpEng.exe) often copy suspicious files to a quarantine folder before analysis, mimicking the behavior of a user copying data.