Threat Advisory

Remcos RAT Delivered via Phishing Campaign Disguises Malware as GST Debit Note

Threat: Phishing Campaign
Targeted Region: India
Targeted Sector: Technology & IT
Criticality: High
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EXECUTIVE SUMMARY:

A phishing campaign is actively targeting users in India by disguising malware as a routine GST debit note. The attack delivers a powerful remote access tool called Remcos RAT through a cleverly constructed multi-stage loader, giving attackers deep and persistent control over infected systems. The infection begins when an unsuspecting victim receives a phishing email carrying a malicious archive attachment.[/subscribe_to_unlock_form]

EXECUTIVE SUMMARY:

A phishing campaign is actively targeting users in India by disguising malware as a routine GST debit note. The attack delivers a powerful remote access tool called Remcos RAT through a cleverly constructed multi-stage loader, giving attackers deep and persistent control over infected systems. The infection begins when an unsuspecting victim receives a phishing email carrying a malicious archive attachment.[emaillocker id="1283"]

Once extracted, the archive drops a file named "GST Debit Note Apr_26 .com," which turns out to be a executable. The file is both packed and unsigned, and it contains embedded Turkish-language artifacts while disguising itself as a legitimate brick-building game to appear completely harmless. The campaign does not stop at Remcos. Further investigation revealed that similar samples linked to the same infrastructure were also delivering Agent Tesla, Phantom Stealer, Dark Cloud, Red Line Stealer, MassLogger variants, Formbook, xworm, and Snake keyloggers.

This strongly points to a loader-as-a-service model, where the delivery infrastructure stays consistent and only the final payload changes. The sheer breadth of this operation makes it a serious and ongoing threat to businesses and individuals across the region.

THREAT PROFILE:

Tactic Technique Id Technique Sub-technique
Initial access T1566.001 Phishing Spearphishing Attachment
Execution T1059.001 Command and Scripting Interpreter PowerShell
Persistence T1547.001 Boot or Logon Autostart Execution Registry Run Keys / Startup Folder
Defence Evasion T1027 Obfuscated Files or Information -
Defence Evasion T1036.005 Masquerading Match Legitimate Resource Name or Location
Credential access T1555.003 Credentials from Password Stores Credentials from Web Browsers
Collection T1005 Data from Local System -
Command and control T1071.001 Application Layer Protocol Web Protocols
Exfiltration T1041 Exfiltration Over C2 Channel -

REFERENCES:

The following reports contain further technical details:
https://labs.k7computing.com/index.php/a-multi-stage-steganographic-loader-campaign-deploying-diverse-payloads-globally/

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