IndiaWhiskey

Hunt Hypothesis

This detection identifies potential adversary activity involving the specific malware signature defined by the IndiaWhiskey YARA rule within the Azure Sentinel environment. Proactive hunting is essential to validate the presence of this threat early and assess its impact before it escalates into a more severe incident, despite the current low severity rating.

YARA Rule

rule IndiaWhiskey
{
	meta:
		copyright = "2015 Novetta Solutions"
		author = "Novetta Threat Research & Interdiction Group - trig@novetta.com"		
		Source = "0c729deec341267c5a9a2271f20266ac3b0775d70436c7770ddc20605088f3b4"
		Description = "Winsec Installer"
		
	strings:
	/*
		// Service installation code
		FF 15 68 30 40 00  call    ds:wsprintfA
		83 C4 18           add     esp, 18h
		8D 85 FC FE FF FF  lea     eax, [ebp+var_104]
		56                 push    esi
		56                 push    esi
		56                 push    esi
		56                 push    esi
		56                 push    esi
		50                 push    eax
		6A 01              push    1
		// some variants have these two lines added
		5E                 pop     esi
		56                 push    esi

		6A 02              push    2
		68 20 01 00 00     push    120h
		68 FF 01 0F 00     push    0F01FFh
		FF 75 0C           push    [ebp+arg_4]
		FF 75 08           push    [ebp+arg_0]
		
		// some variants have the next line as a push {reg} or push {stack var}
		53                 push    ebx
		//or
		FF 75 FC           push    [ebp+var_4]

		FF 15 E4 49 40 00  call    CreateServiceA
	*/

	$a = {FF 15 [4] 83 C4 18 8D [5] 5? 5? 5? 5? 5? 5? 6A 01	[0-2] 6A 02 68 20 01 00 00 68 FF 01 0F 00 FF 75 ?? FF 75 ?? (5? | FF 75 ??) FF 15}

	condition:
		$a in ((pe.sections[pe.section_index(".text")].raw_data_offset)..(pe.sections[pe.section_index(".text")].raw_data_offset + pe.sections[pe.section_index(".text")].raw_data_size))
}

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.

• Source Rule

False Positive Guidance

Here are 5 specific false positive scenarios for the IndiaWhiskey detection rule in an enterprise environment, along with suggested filters or exclusions:

• Scheduled Antivirus Definition Updates via WSUS

  • Scenario: The Windows Update Service (wuauserv.exe) downloads and installs large security definition updates from Microsoft Update servers located in the region covered by the IndiaWhiskey logic. These updates often involve temporary file extraction and execution patterns that mimic the rule’s signature for legitimate administrative maintenance.
  • Filter/Exclusion: Add an exclusion for wuauserv.exe when the parent process is svchost.exe (specifically the “NetworkService” group) and the destination IP belongs to the Microsoft Update CDN range (e.g., 137.254.x.x).

• Automated Backup Jobs using Veeam or Commvault

  • Scenario: Enterprise backup agents running nightly jobs create temporary staging files and execute compression scripts that match the IndiaWhiskey YARA pattern. This is common when backing up SQL databases or virtual machine snapshots where large data blocks are processed in a manner similar to the rule’s detection logic.
  • Filter/Exclusion: Exclude processes named VeeamAgent.exe (or commvault_agent.exe) and their child processes (vbragent.exe, cvdbsrvr.exe) originating from the “Backup-Server” OU, provided the file path contains \Program Files\Veeam\.

• Endpoint Detection and Response (EDR) Self-Scans

  • Scenario: The organization’s EDR solution (e.g., CrowdStrike Falcon or Microsoft Defender for Endpoint) performs a scheduled “Quick Scan” or “Deep Scan.” During this process, the EDR engine injects code into running processes to analyze memory and file integrity, which frequently triggers the IndiaWh