Adversaries may manipulate files as part of the CRASHOVERRIDE wiper campaign to exfiltrate data or disrupt systems. SOC teams should proactively hunt for these file manipulation patterns in Azure Sentinel to identify potential wiper activity early and mitigate impact.
YARA Rule
rule dragos_crashoverride_wiperFileManipulation {
meta:
description = "File manipulation actions associated with CRASHOVERRIDE wiper"
author = "Dragos Inc"
reference = "https://dragos.com/blog/crashoverride/CrashOverride-01.pdf"
strings:
$s0 = { 6a 00 68 80 00 00 00 6a 03 6a 00 6a 02 8b f9 68 00 00 00 40 57 ff 15 1c ?? ?? ?? 8b d8 }
$s2 = { 6a 00 50 57 56 53 ff 15 4c ?? ?? ?? 56 }
condition:
all of them
}
This YARA rule can be deployed in the following contexts:
This rule contains 2 string patterns in its detection logic.
Scenario: Scheduled System Maintenance Job
Description: A legitimate scheduled task runs a script that modifies system files during routine maintenance.
Filter/Exclusion: process.name != "schtasks.exe" OR file.path != "C:\Windows\System32\*"
Scenario: Admin Performing File Cleanup
Description: An administrator manually deletes temporary files or logs using tools like del or rm in a command prompt.
Filter/Exclusion: process.name != "cmd.exe" OR file.path != "C:\Windows\Temp\*"
Scenario: Software Update Deployment
Description: A patch management tool like Microsoft Endpoint Configuration Manager (MECM) or SCCM performs file replacement during an update.
Filter/Exclusion: process.name != "msiexec.exe" OR file.path != "C:\Windows\Temp\*"
Scenario: Antivirus Quarantine Operation
Description: Antivirus software like Windows Defender or Bitdefender quarantines malicious files, which may trigger file manipulation alerts.
Filter/Exclusion: process.name != "MsMpEng.exe" OR file.path != "C:\ProgramData\Microsoft\Windows Defender\Quarantine\*"
Scenario: Database Backup and Restore
Description: A database administrator performs a backup or restore operation using tools like sqlcmd or mysqldump, which may involve file manipulation.
Filter/Exclusion: process.name != "sqlcmd.exe" OR file.path != "C:\Program Files\MySQL\*"