Polish banking malware

Hunt Hypothesis

Polish banking malware is likely being used to exfiltrate sensitive financial data through covert network communications. SOC teams should proactively hunt for this behavior in Azure Sentinel to identify and mitigate potential financial theft before significant damage occurs.

YARA Rule

rule Hsdfihdf: banking malware 
{
meta:
	author = "Adam Ziaja <[email protected]> http://adamziaja.com"
	date = "2014-04-06"
	description = "Polish banking malware"
	hash0 = "db1675c74a444fd35383d9a45631cada"
	hash1 = "f48ba39df38056449a3e9a1a7289f657"
	filetype = "exe"
strings:
	$s0 = "ANSI_CHARSET"
	$s1 = "][Vee_d_["
	$s2 = "qfcD:6<"
	$s3 = "%-%/%1%3%5%7%9%;%"
	$s4 = "imhzxsc\\WWKD<.)w"
	$s5 = "Vzlarf\\]VOZVMskf"
	$s6 = "JKWFAp\\Z"
	$s7 = "<aLLwhg"
	$s8 = "bdLeftToRight"
	$s9 = "F/.pTC7"
	$s10 = "O><8,)-$ "
	$s11 = "mjeUB>D.'8)5\\\\vhe["
	$s12 = "JGiVRk[W]PL("
	$s13 = "zwWNNG:8"
	$s14 = "zv7,'$"
	$a0 = "#hsdfihdf"
	$a1 = "polska.irc.pl"
	$b0 = "[email protected]"
	$b1 = "[email protected]"
	$b2 = "[email protected]"
	$c0 = "cyberpunks.pl"
	$c1 = "kaper.phrack.pl"
	$c2 = "serwer.uk.to"
	$c3 = "ns1.ipv4.hu"
	$c4 = "scorebot.koth.hu"
	$c5 = "esopoland.pl"
condition:
	14 of ($s*) or all of ($a*) or 1 of ($b*) or 2 of ($c*)
}

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 26 string patterns in its detection logic.

• Source Rule

False Positive Guidance

• Scenario: Scheduled System Maintenance Job
  Description: A legitimate system maintenance job (e.g., schtasks.exe or Task Scheduler) is running a script that mimics the behavior of Polish banking malware, such as downloading or executing payloads.
  Filter/Exclusion: Exclude tasks associated with known system maintenance tools (e.g., schtasks.exe with TaskName containing “Maintenance” or “Cleanup”).

• Scenario: Admin Performing Remote Desktop Session
  Description: An administrator is using Remote Desktop Protocol (RDP) to access a server, and the session is flagged due to unusual network activity or file access patterns.
  Filter/Exclusion: Exclude RDP sessions by checking the ProcessName field for mstsc.exe or rdpclip.exe, or by filtering based on the User field for known admin accounts.

• Scenario: Legitimate File Download from Trusted Repository
  Description: A user is downloading a legitimate file (e.g., a banking tool or script) from a trusted internal repository (e.g., using wget or curl), which triggers the detection due to similar file hashes or network behavior.
  Filter/Exclusion: Exclude downloads from internal repositories by checking the SourceIP or URL field against known internal IP ranges or repository URLs.

• Scenario: PowerShell Script for System Monitoring
  Description: A PowerShell script (e.g., powershell.exe) is being used by the IT department to monitor system performance or log file activity, which may resemble the behavior of malware.
  Filter/Exclusion: Exclude PowerShell scripts by checking the CommandLine field for known monitoring tools (e.g., Get-EventLog, Get-Service, or scripts with Monitoring in the command).

• Scenario: Antivirus or EDR Tool Performing Full Scan