Threat Advisory

Advisory for GammaDrop Malware Deployment via Spoofed Emails

Threat: Malware
Threat Actor Name: Gamaredon
Threat Actor Type: APT
Targeted Region: Ukraine
Threat Actor Region: Ukraine
Targeted Sector: Technology & IT, Government & Defense
Criticality: High
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EXECUTIVE SUMMARY

Gamaredon's threat campaign targets Ukrainian state institutions with the goal of data theft. These emails, often spoofed or sent from compromised government accounts, deliver persistent, multi-stage VBScript downloaders that profile the infected system. The attackers' ultimate goal is to steal sensitive information, and the campaign has been ongoing for several months, with new waves emerging at a roughly monthly cadence. The threat actors behind Gamaredon have been exploiting the CVE-2025-8088 vulnerability.[/subscribe_to_unlock_form]

EXECUTIVE SUMMARY

Gamaredon's threat campaign targets Ukrainian state institutions with the goal of data theft. These emails, often spoofed or sent from compromised government accounts, deliver persistent, multi-stage VBScript downloaders that profile the infected system. The attackers' ultimate goal is to steal sensitive information, and the campaign has been ongoing for several months, with new waves emerging at a roughly monthly cadence. The threat actors behind Gamaredon have been exploiting the CVE-2025-8088 vulnerability.[emaillocker id="1283"]

The malware infection chain begins with a spoofed email, which delivers a RAR archive containing a VBScript payload, GammaDrop. This payload fetches a remote HTA file, GammaLoad, from a Cloudflare Workers C2 server and executes it. The HTA file establishes persistence via a RunOnce registry key and beacons victim data to the C2 server, enabling the operator to selectively deliver a tailored payload. The malware also uses a unique, redundant path traversal pattern to bypass WinRAR path traversal mitigations.

Once inside the system, the malware establishes persistence and beacons victim data to the C2 server, allowing the attacker to selectively deliver a tailored payload. Gamaredon's tooling is auto-generated and parameterized per wave, producing samples that vary in their communication parameters with superficial code changes that preserve the same underlying functionality. However, the payload delivered via GammaLoad appears to be operator-controlled and is not automatically served. The attackers have been using a unique, redundant path traversal pattern to bypass WinRAR path traversal mitigations, making it difficult to detect the malware. The campaign has been ongoing, with new waves emerging at a roughly monthly cadence, and organisations should be on high alert to prevent a potential breach.

THREAT PROFILE:

Tactic Technique ID Technique Sub-technique
Resource Development T1583.003 Acquire Infrastructure Virtual Private Server
Initial Access T1566.001 Phishing Spearphishing Attachment
Defense Evasion T1218.005 System Binary Proxy Execution Mshta
Execution T1059.005 Command and Scripting Interpreter Visual Basic
Persistence T1547.001 Boot or Logon Autostart Execution Registry Run Keys / Startup Folder
Defense Evasion T1564.004 Hide Artifacts NTFS File Attributes
Defense Evasion T1027 Obfuscated Files or Information
Initial Access T1078 Valid Accounts
Discovery T1082 System Information Discovery
Discovery T1047 Windows Management Instrumentation
Command and Control T1071.001 Application Layer Protocol Web Protocols
Command and Control T1008 Fallback Channels

REFERENCES:

reports contain further technical details:
https://harfanglab.io/insidethelab/gamaredon-gammadrop-gammaload/

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