sitrof fortis scar

Hunt Hypothesis

This detection targets adversary behavior involving the execution of the Sitorf Fortis Scar malware, which often indicates an initial foothold or lateral movement attempt within the network. The SOC team should proactively hunt for this signature in Azure Sentinel to identify early-stage compromises that may exhibit low severity but possess the potential for significant downstream impact if left unmonitored.

YARA Rule

rule sitrof_fortis_scar {

    meta:
        author = "J from THL <j@techhelplist.com>"
        date = "2018/23"
        reference1 = "https://www.virustotal.com/#/file/59ab6cb69712d82f3e13973ecc7e7d2060914cea6238d338203a69bac95fd96c/community"
	reference2 = "ETPRO rule 2806032, ETPRO TROJAN Win32.Scar.hhrw POST"
	version = 2
        maltype = "Stealer"
        filetype = "memory"

    strings:
	
	$a = "?get&version"
	$b = "?reg&ver="
	$c = "?get&exe"
	$d = "?get&download"
	$e = "?get&module"
	$f = "&ver="
	$g = "&comp="
	$h = "&addinfo="
	$i = "%s@%s; %s %s \"%s\" processor(s)"
	$j = "User-Agent: fortis"

    condition:
        6 of them
}

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 10 string patterns in its detection logic.

• Source Rule

False Positive Guidance

Here are 4 specific false positive scenarios for the sitrof_fortis_scar detection rule in an enterprise environment, including recommended filters and exclusions:

• Endpoint Protection Scanning Cycles

  • Scenario: The YARA rule may trigger during routine file integrity scans performed by endpoint protection agents (e.g., CrowdStrike Falcon, SentinelOne, or Microsoft Defender for Endpoint) when they analyze the sitrof_fortis_scar binary or its associated configuration files in the %ProgramFiles% directory.
  • Filter/Exclusion: Exclude processes where the parent process is the specific EDR service (e.g., csagent.exe, ssosd.exe, or MsMpEng.exe) and the file path matches the known installation directory of the Sitrof Fortis Scar application.

• Scheduled Patch Management Deployments

  • Scenario: Automated patching tools like Microsoft SCCM (Configuration Manager) or Ivanti Endpoint Manager often execute scripts to update the Sitrof Fortis Scar agent during maintenance windows. These deployment tasks involve reading and writing to the application’s registry keys and binary files, which can mimic the detection logic of a new installation or modification event.
  • Filter/Exclusion: Create an exclusion for events occurring between 02:00 and 04:00 UTC on weekdays where the initiating user account is a dedicated service account (e.g., svc-patch-deploy) and the command line arguments contain keywords like /install, /update, or specific SCCM package IDs.

• Administrative Configuration Backups

  • Scenario: System administrators frequently use backup solutions such as Veeam Backup & Replication or Commvault to snapshot critical security tools. When these agents access the sitrof_fortis_scar data directories