Cavalry Werewolf hacker group attacks Russian state institutions

SUMMARY :

A Russian government organization was targeted by the Cavalry Werewolf hacker group, aiming to collect confidential information and network data. The attack began with phishing emails containing malware disguised as documents. The group utilized various tools including backdoors, trojans, and modified legitimate programs. They employed open-source software, reverse-shell backdoors, and Telegram API for control. The attackers focused on information gathering, network configuration, and establishing persistence in compromised systems. Their tactics included using Windows built-in tools, modifying the registry, and exploiting public directories for malware deployment. The group's sophisticated approach and diverse toolset highlight the evolving threat landscape for government institutions.

OPENCTI LABELS :

open-source tools,network infiltration,data theft,backdoors,phishing,reverse-shell,russian government,trojan.packed2.49708,backdoor.reverseshell.10,trojan.inject5.57968,trojan.siggen31.54011,backdoor.tunnel.41,trojan.filespynet.5,backdoor.shellnet.1,backdoor.shellnet.2,bat.downloader.1138,telegram api,backdoor.reverseproxy.1,backdoor.siggen2.5463,trojan.packed2.49862,backdoor.rshell.169


AI COMMENTARY :

1. The recent campaign launched by the Cavalry Werewolf hacker group against Russian state institutions underscores the growing sophistication of cyber adversaries targeting government networks. In this attack, the adversaries sought to steal confidential information and network configurations from a high-value government organization. The operation commenced with a meticulously crafted phishing campaign in which emails containing malicious attachments were used to lure unsuspecting employees into opening what appeared to be legitimate documents. Once executed, these files deployed a multi-stage malware arsenal designed to establish a foothold within the victim’s environment and exfiltrate sensitive data.

2. At the heart of this intrusion lies a diverse set of tools and backdoors, including variants such as trojan.packed2.49708, trojan.packed2.49862, backdoor.reverseshell.10, backdoor.rshell.169, and backdoor.reverseproxy.1. Each component played a distinct role in the intrusion lifecycle. The packed trojans served to evade detection by security software, while the reverse-shell and reverse-proxy backdoors enabled the attackers to maintain stealthy, persistent access to compromised systems. The trojan.inject5.57968 and trojan.siggen31.54011 modules were leveraged to inject payloads into legitimate processes, further obfuscating their presence and complicating incident response efforts.

3. The group’s choice of open-source tools and legitimate Windows utilities demonstrates an advanced understanding of operational security. By abusing built-in commands and registry modifications, the attackers sidestepped many endpoint defenses and avoided raising immediate alarms. The backdoor.shellnet.1 and backdoor.shellnet.2 components facilitated covert command execution, while bat.downloader.1138 was used to fetch additional payloads from public directories. The trojan.filespynet.5 payload specialized in harvesting documents and credentials, systematically siphoning data back to remote servers controlled by the threat actors.

4. For command and control, the attackers integrated the Telegram API to orchestrate their remote operations. This choice allowed them to blend malicious traffic with legitimate messaging protocols, making network detection challenging. The backdoor.tunnel.41 and backdoor.siggen2.5463 further supported encrypted communication channels, ensuring that the exfiltrated data and remote commands remained hidden from inspection tools. The use of a reverse-shell strategy, typified by both backdoor.reverseshell.10 and backdoor.rshell.169, granted near-real-time interactive access to compromised hosts for reconnaissance and lateral movement.

5. The operational objectives of Cavalry Werewolf extended beyond simple data theft. By mapping network topologies, altering network configurations, and deploying persistent registry entries, the group sought long-term control over targeted systems. Their sophisticated approach to establishing persistence and leveraging open-source infrastructure highlights the evolving threat landscape facing government institutions. The combination of custom malware variants and legitimate software abuse underscores the importance of a layered defense strategy capable of detecting both known signatures and anomalous behaviors.

6. In light of this incident, organizations must enhance their email gateways with advanced malware sandboxing, implement strict application whitelisting, and maintain real-time monitoring of unusual registry changes. Deploying network segmentation and multi-factor authentication can limit an attacker’s lateral movement and reduce the impact of compromised credentials. Finally, incident response teams should be prepared to identify and dismantle Telegram API‐based command channels, as these have become a favorite among adversaries seeking reliable, covert communications.

7. The Cavalry Werewolf operation targeting Russian government bodies serves as a stark reminder that threat actors will continuously refine their toolsets and tactics. By studying the group’s use of reverse shells, trojan injection, and open-source tools, defenders can better anticipate and counter similar campaigns. Vigilance, collaboration, and proactive security measures remain vital to safeguarding critical infrastructure against such persistent and well-resourced adversaries.


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Cavalry Werewolf hacker group attacks Russian state institutions