Detects Sofacy Malware mentioned in PaloAltoNetworks APT report

Hunt Hypothesis

Sofacy malware is being executed in the environment, leveraging techniques associated with a known APT group to exfiltrate data and establish persistence. SOC teams should proactively hunt for this behavior to identify and mitigate advanced persistent threats before significant data loss occurs.

YARA Rule

rule Sofacy_Jun16_Sample3 
{

    meta:
        description = "Detects Sofacy Malware mentioned in PaloAltoNetworks APT report"
        author = "Florian Roth"
        reference = "http://goo.gl/mzAa97"
        date = "2016-06-14"
        score = 85
        hash1 = "c2551c4e6521ac72982cb952503a2e6f016356e02ee31dea36c713141d4f3785"
   
    strings:
        $s1 = "ASLIiasiuqpssuqkl713h" fullword wide
   
    condition:
        uint16(0) == 0x5a4d and filesize < 200KB and $s1
}

Deployment Notes

This YARA rule can be deployed in the following contexts:

• Microsoft Defender for Endpoint — Custom indicators / advanced hunting
• Email Gateway — Attachment scanning
• File Share Monitoring — Periodic scanning of shared drives
• YARA CLI — Manual threat hunting on endpoints

This rule contains 1 string patterns in its detection logic.

References

• http://goo.gl/mzAa97
• Source Rule

False Positive Guidance

• Scenario: A system administrator is using PowerShell to run a scheduled job for system maintenance, which includes executing a script that matches the known Sofacy malware signature.
  Filter/Exclusion: Exclude processes initiated by the Task Scheduler or PowerShell scripts with a known admin task name (e.g., SystemMaintenanceJob).

• Scenario: A security tool like Splunk is performing a log aggregation task that includes parsing and exporting logs to a file, which inadvertently matches the Sofacy malware detection pattern.
  Filter/Exclusion: Exclude processes associated with Splunk or any known log management tools, or filter based on the file path where logs are stored (e.g., /var/log/splunk/).

• Scenario: A database administrator is using MySQL to run a scheduled backup job, which includes executing a script that contains a string matching the Sofacy malware signature.
  Filter/Exclusion: Exclude processes initiated by MySQL or any backup-related tasks, or filter based on the command line arguments containing backup or snapshot.

• Scenario: A DevOps engineer is using Ansible to deploy configuration changes across the network, and one of the scripts used contains a string that matches the Sofacy malware signature.
  Filter/Exclusion: Exclude processes initiated by Ansible or filter based on the user context (e.g., ansible user or root with a known DevOps task).

• Scenario: A system update task using WSUS (Windows Server Update Services) is running, and the update script includes a string that matches the Sofacy malware signature.
  Filter/Exclusion: Exclude processes related to WSUS or filter based on the command line arguments containing update or patch.