CommentCrew-threat-apt1 detects potential adversary behavior involving suspicious comment creation or modification in Azure resources, which may indicate reconnaissance or initial compromise activities. SOC teams should proactively hunt for this behavior to identify early-stage threats and prevent lateral movement within the Azure environment.
YARA Rule
rule KURTON_APT1
{
meta:
author = "AlienVault Labs"
info = "CommentCrew-threat-apt1"
strings:
$s1 = "Mozilla/4.0 (compatible; MSIE8.0; Windows NT 5.1)" wide ascii
$s2 = "!(*@)(!@PORT!(*@)(!@URL" wide ascii
$s3 = "MyTmpFile.Dat" wide ascii
$s4 = "SvcHost.DLL.log" wide ascii
condition:
all of them
}
This YARA rule can be deployed in the following contexts:
This rule contains 4 string patterns in its detection logic.
Scenario: Scheduled System Maintenance Job
Description: A legitimate scheduled task runs a script that includes a comment with “Crew” in the log, such as a maintenance script that updates system configurations.
Filter/Exclusion: Exclude events where the source is a known system maintenance tool (e.g., schtasks.exe, task scheduler), or filter by process name or command line containing maintenance, update, or backup.
Scenario: Admin User Commenting on a Log File
Description: An admin user manually edits a log file or adds a comment in a script to indicate a specific action, such as “Crew: system reboot initiated.”
Filter/Exclusion: Exclude events where the user is a known admin (e.g., Administrator, Domain Admins) or where the command line includes echo, log, or comment.
Scenario: Automated Backup Script with Metadata
Description: A backup script includes a comment like “Crew: backup initiated” to document the job in the script or log.
Filter/Exclusion: Exclude events where the process is a known backup tool (e.g., Veeam, Acronis, rsync), or filter by command line containing backup, snapshot, or restore.
Scenario: User-Generated Documentation or Notes
Description: A user writes a comment in a script or log file for internal documentation, such as “Crew: this script is used for daily reporting.”
Filter/Exclusion: Exclude events where the user is part of a documentation team or where the command line includes note, doc, or comment.
Scenario: Log Analysis Tool Generating Comments
Description: A log analysis tool (e.g., Splunk, ELK Stack) adds a comment in the