Cyber Espionage Alliance: Turla Exploits Gamaredon’s Access in Attacks on Ukraine
A startling evolution in cyber warfare tactics has been uncovered, revealing an unprecedented collaboration between two of Russia’s most prominent Advanced Persistent Threat (APT) groups. In a series of targeted attacks against a Ukrainian defense organization, the highly sophisticated Turla group was observed using network access previously gained by the prolific Gamaredon group.
This development marks a significant shift in the operational tactics of state-sponsored threat actors, suggesting a new level of cooperation and specialization. While Gamaredon is known for its widespread, “noisy” campaigns to establish initial footholds, Turla is infamous for its stealthy, surgical strikes aimed at long-term espionage.
The “Foot in the Door”: Gamaredon’s Initial Breach
The attack chain begins with Gamaredon, an APT group known for its relentless phishing campaigns. Using spear-phishing emails containing malicious documents or LNK files, the group successfully compromises target systems. Once inside, their malware establishes persistence, creating a stable backdoor into the victim’s network.
In this operational model, Gamaredon’s primary role was to secure the initial network compromise. Their methods, while effective at gaining access, often generate significant security alerts. However, this initial, less sophisticated breach serves as a crucial stepping stone for a far more dangerous threat.
The Escalation: Turla Deploys Its Advanced Arsenal
Once Gamaredon established a presence, a different, more advanced set of activities began. Security researchers observed that Turla operators leveraged this pre-existing access to deploy their own highly sophisticated espionage tools. Instead of conducting their own risky initial breach operations, Turla effectively used Gamaredon’s access as an entry point.
This hand-off allowed Turla to bypass the initial, most visible stages of an attack and proceed directly to its core mission: intelligence gathering. The primary payload deployed by Turla was a variant of its signature malware, designed for stealth and long-term persistence.
A Closer Look at Turla’s Espionage Toolkit
After gaining access, Turla deployed a new, custom delivery mechanism to install its malware. This involved a .NET executable that, when run, would launch a VBScript. This script then executed the final payload in memory, a technique used to evade detection by security software that scans files on disk.
The primary payload was the notorious Kazuar backdoor, a complex tool used for long-term intelligence gathering. Kazuar provides its operators with extensive remote control over a compromised system, enabling them to steal sensitive documents, log keystrokes, and execute further commands. Its deployment signifies a serious, high-level espionage objective.
A Game-Changer for Cyber Defense
The collaboration between a high-volume, low-sophistication group like Gamaredon and a high-stealth, surgical group like Turla has profound implications for cybersecurity:
- Complicated Attribution: It becomes difficult to determine who is ultimately responsible for the attack. Is it the group that gained initial access or the one that exploited it? This tactic complicates attribution and allows highly skilled groups to operate with an additional layer of obfuscation.
- Specialized Roles: This suggests a specialization of duties among threat groups, where some act as “access brokers” for others. This creates a more efficient and dangerous cybercrime ecosystem.
- Heightened Threat Level: An initial compromise by a group like Gamaredon can no longer be dismissed as a low-level threat. It could be the precursor to a far more severe attack by an elite APT group.
How to Defend Against Layered Cyber Threats
This new paradigm requires a defense-in-depth security strategy that accounts for multi-stage, multi-operator attacks. Organizations must assume that any breach could be exploited by a more advanced actor.
- Strengthen Initial Defenses: Since these attacks often start with phishing, implementing advanced email security filters and robust employee training is the first critical line of defense.
- Assume Breach and Hunt for Threats: Do not stop at cleaning up an initial infection. Utilize Endpoint Detection and Response (EDR) tools to actively hunt for secondary payloads, unusual network traffic, and evidence of lateral movement.
- Enforce Network Segmentation: By segmenting your network, you can make it significantly harder for attackers who gain an initial foothold on one machine to move laterally and access more critical systems.
- Maintain Vigilant Monitoring: Continuously monitor for indicators of compromise (IoCs) associated with both prolific access brokers like Gamaredon and elite APTs like Turla. A seemingly minor alert could be the signal of a much larger intrusion.
The alliance between Gamaredon and Turla is a clear signal that the landscape of cyber espionage is constantly evolving. Defenders must adapt their strategies to recognize that even a common threat can be the gateway to a far more devastating and targeted attack.
Source: https://securityaffairs.com/182404/apt/eset-uncovers-gamaredon-turla-collaboration-in-ukraine-cyberattacks.html
