Ethical Hacking News
Gamaredon, a Russia-linked APT group, has launched a modular spy campaign on Ukrainian targets using a previously unpatched vulnerability in WinRAR to gain initial access. The campaign features a layered threat model with various stages of execution, each utilizing different techniques and evasion methods to remain stealthy. This threat highlights the ongoing cat-and-mouse game between cybersecurity professionals and APT groups like Gamaredon. To stay updated on this ongoing threat, readers can follow Sekoia's intelligence feed for the latest information.
Gamaredon, a Russia-linked APT group, has been actively deploying a modular spy campaign on Ukrainian targets. The group uses a previously unpatched vulnerability in WinRAR to gain initial access and employs a complex infection chain with multiple layers. Gamaredon's modular design allows it to persistently evade detection and stay stealthy even when defenders attempt to clean one layer. The group has been using sophisticated tactics such as embedding tracking pixels, exploiting vulnerabilities, and weaponizing USB drives for physical propagation. Gamaredon's new campaign involves fileless operations, making it challenging for defenders to detect and respond to the attack. A complete wipe is the safest remediation path for any host confirmed infected by this chain due to the dead-drop resolution. The Sekoia report reveals a standardized nomenclature using the "Gamma" prefix, providing valuable insight into Gamaredon's complex operations.
The world of cyber espionage has witnessed numerous sophisticated attacks in recent years, but one threat actor stands out for its sheer adaptability and resilience - Gamaredon. In a recent report published by Sekoia, the researchers revealed that this Russia-linked Advanced Persistent Threat (APT) group has been actively deploying a modular spy campaign on Ukrainian targets, leveraging a previously un patched vulnerability in WinRAR to gain initial access.
The report highlights the complexity of Gamaredon's infection chain, which hops through various layers before arriving at an operator-controlled server. Each resolved URL gets written to the registry for the next stage to read, ensuring that the malware remains stealthy and evasive even when defenders attempt to clean one layer. The group's modular design allows it to persistently evade detection, making it a formidable opponent in the world of cyber espionage.
The Sekoia report reveals that Gamaredon has been using certain techniques for a long time, such as embedding 1√ó1 tracking pixels to validate victim engagement, exploiting archive path traversal vulnerabilities, and weaponizing USB drives for physical propagation. These tactics demonstrate a level of sophistication that is unmatched by many other APT groups.
However, what's new in this campaign is the infrastructure concealment: running almost entirely in memory, storing payloads in ADS, resolving C2s through Telegram and Cloudflare, and exfiltrating data in HTTP headers rather than request bodies. This shift towards fileless operations makes it increasingly challenging for defenders to detect and respond to the attack.
Sekoia notes that for any host confirmed infected by this chain, a complete wipe is the safest remediation path, because GammaWorm's dead-drop resolution lets operators push fresh payloads faster than cleaning attempts can keep up. This highlights the ongoing cat-and-mouse game between cybersecurity professionals and APT groups like Gamaredon.
The report also reveals that for any host confirmed infected by this chain, a complete wipe is the safest remediation path, because GammaWorm's dead-drop resolution lets operators push fresh payloads faster than cleaning attempts can keep up. This highlights the ongoing cat-and-mouse game between cybersecurity professionals and APT groups like Gamaredon.
Sekoia has now aligned the naming under a single taxonomy using the “Gamma” prefix: GammaPhish for initial access, GammaLoad for staging, GammaWorm for propagation, GammaSteel for data theft, and GammaWipe for destruction. This standardized nomenclature provides valuable insight into the complex operations of Gamaredon.
In January 2026, the experts observed the threat actor using a weaponized XHTML file, likely delivered as a spearphishing attachment. Opening it silently triggers a 1×1 pixel tracking request to a Supabase endpoint, confirming to the operator that the victim opened the lure. This tracking technique dates back to at least 2018, which tells you something about how little Gamaredon needs to innovate when the basics still work.
The XHTML then uses HTML smuggling to deliver a RAR archive that exploits CVE-2025-8088, a critical path traversal flaw in WinRAR patched in version 7.13. The archive looks like it contains one PDF but actually contains two files: the visible decoy and an HTA file that path-traversal extracts directly into the user’s Windows Startup folder.
Upon execution, the HTA file leverages mshta.exe to call a remote payload hosted on a C2 server. Sekoia couldn’t retrieve GammaLoad directly from this stage because C2 servers were unresponsive during testing but forensic artifacts from compromised hosts filled in the picture.
The full indicator set, including file hashes for GammaPhish and GammaWorm, dead drop resolver URLs, and the single confirmed C2 IP are published at the end of the Sekoia report. The full indicator set is available through Sekoia’s intelligence feed. Readers can stay updated on this ongoing threat by following Sekoia's intelligence feed.
Related Information:
https://www.ethicalhackingnews.com/articles/Gamaredons-Modular-Malware-Campaign-A-Layered-Threat-to-Global-Security-ehn.shtml
https://securityaffairs.com/193112/intelligence/gamaredon-uses-winrar-vulnerability-to-launch-modular-spy-campaign-on-ukrainian-targets.html
Published: Thu Jun 4 07:05:52 2026 by llama3.2 3B Q4_K_M
