The Mini Duke Implant by APT29 is a high-impact adversary behavior that indicates a persistent, stealthy compromise, often used for long-term data exfiltration and command and control. SOC teams should proactively hunt for this behavior in Azure Sentinel to identify and mitigate advanced persistent threats before significant data loss occurs.
YARA Rule
rule IMPLANT_11_v12 {
meta:
description = "Mini Duke Implant by APT29"
author = "US CERT"
reference = "https://www.us-cert.gov/ncas/current-activity/2017/02/10/Enhanced-Analysis-GRIZZLY-STEPPE"
date = "2017-02-10"
score = 85
strings:
$STR1 = {63 74 00 00} // ct
$STR2 = {72 6F 74 65} // rote
$STR3 = {75 61 6C 50} // triV
$STR4 = {56 69 72 74} // Plau
$STR5 = { e8 00 00 00 00 }
$STR6 = { 64 FF 35 00 00 00 00 }
$STR7 = {D2 C0}
$STR8 = /\x63\x74\x00\x00.{3,20}\x72\x6F\x74\x65.{3,20}\x75\x61\x6C\x50.{3,20}\x56\x69\x72\x74/
condition:
(uint16(0) == 0x5A4D) and #STR5 > 4 and all of them
}This YARA rule can be deployed in the following contexts:
This rule contains 8 string patterns in its detection logic.
Scenario: Scheduled System Maintenance Task
Description: A legitimate scheduled task runs a script that includes PowerShell commands similar to those used by Mini Duke.
Filter/Exclusion: Exclude tasks with TaskName containing “Maintenance” or “SystemUpdate” and check for TaskScheduler source.
Scenario: Admin Performing Remote PowerShell Management
Description: An administrator uses PowerShell remoting to manage remote systems, which may include commands that resemble Mini Duke’s C2 communication.
Filter/Exclusion: Exclude events where ProcessName is powershell.exe and CommandLine includes -Command with Invoke-Command or Enter-PSSession.
Scenario: Database Backup Job Using PowerShell
Description: A database backup script uses PowerShell to interact with SQL Server, which may include command-line arguments that match Mini Duke’s behavior.
Filter/Exclusion: Exclude events where ProcessName is powershell.exe and CommandLine includes sqlcmd or Invoke-Sqlcmd.
Scenario: Log Collection and Analysis Tool Execution
Description: A log analysis tool like Splunk or ELK Stack runs a script that uses PowerShell to parse logs, which may include similar command structures.
Filter/Exclusion: Exclude events where ProcessName is splunk.exe, elasticsearch.exe, or logstash.exe and check for known log analysis tool signatures.
Scenario: Software Update Deployment via Group Policy
Description: A Group Policy Object (GPO) triggers a script that uses PowerShell to deploy updates, which may include command-line arguments that resemble Mini Duke’s C2.
Filter/Exclusion: Exclude events where ProcessName is gpupdate.exe or GroupPolicy.exe and check for PolicyName containing “Update” or “Patch”.