The detection rule identifies potential malicious activity associated with a specific MD5 hash, which may indicate the presence of a known or unknown adversary payload. SOC teams should proactively hunt for this behavior in Azure Sentinel to identify and mitigate early-stage threats that may evade traditional detection methods.
YARA Rule
rule md5_f797dd5d8e13fe5c8898dbe3beb3cc5b {
strings: $ = "echo(\"FILE_Bad\");"
condition: any of them
}This YARA rule can be deployed in the following contexts:
Scenario: A system backup tool (e.g., Veeam, Acronis) generates a temporary file with the MD5 hash f797dd5d8e13fe5c8898dbe3beb3cc5b during a backup process.
Filter/Exclusion: Check for file paths containing backup, snapshot, or temp directories, or filter by process name like veeam.exe or acronis.exe.
Scenario: A scheduled job (e.g., Windows Task Scheduler or cron job) runs a legitimate script or tool (e.g., rsync, tar, or PowerShell) that temporarily creates a file with the same MD5 hash.
Filter/Exclusion: Filter based on process owner (e.g., SYSTEM, root, or specific service accounts), or check for presence of scheduled task names or cron job entries.
Scenario: A legitimate software update (e.g., Microsoft Windows Update, Adobe Acrobat Updater) includes a file with the MD5 hash f797dd5d8e13fe5c8898dbe3beb3cc5b as part of its installation package.
Filter/Exclusion: Filter based on file paths containing update, patch, or installer, or check for known update service processes like wuauclt.exe or updater.exe.
Scenario: A system management tool (e.g., Microsoft Intune, SCCM, or Puppet) generates a temporary file during configuration deployment that matches the hash.
Filter/Exclusion: Filter by process names like ccmexec.exe, puppet.exe, or intunewsm.exe, or check for file paths containing config, deployment, or management.
Scenario: A legitimate log file (e.g., from