A recent cyber threat has emerged, linked to the nation-state group known as APT28, which has exploited a vulnerability in the Microsoft Windows Print Spooler service to distribute a custom malware variant named GooseEgg. This security flaw, tracked as CVE-2022-38028, received a high CVSS score of 7.8 and has been actively weaponized since at least June 2020, with potential usage dating back to April 2019. Microsoft addressed this vulnerability in October 2022, after it was reported by the U.S. National Security Agency (NSA).
APT28, also referred to as Fancy Bear and Forest Blizzard, has targeted various sectors, specifically focusing on government entities, educational institutions, and transportation services in Ukraine, Western Europe, and North America. Through a refined technique, the group utilized the Print Spooler flaw to escalate privileges and execute malicious scripts.
The malware serves as a post-compromise tool enabling the threat actors to execute commands with elevated permissions. By modifying a JavaScript constraints file, APT28 has effectively gained SYSTEM-level access to compromised systems. As discovered by Microsoft researchers, GooseEgg can trigger exploits and initiate different applications based on specified parameters.
This cyber operation suggests a sophisticated understanding of initial access and privilege escalation tactics aligned with the MITRE ATT&CK framework. By gaining elevated access, APT28 can conduct additional malicious activities such as remote code execution and lateral movement within networks. Specifically, the tactics of privilege escalation and command and control (C2) may have been employed to facilitate these actions.
APT28 operates under the auspices of Unit 26165 of the Russian General Staff Main Intelligence Directorate (GRU). The group, which has been active for almost 15 years, predominantly focuses on intelligence collection to further Russian foreign policy interests. Their recent activities underline an ability to adapt quickly to new exploits, as evidenced by their manipulation of a privilege escalation flaw in Microsoft Outlook and a vulnerability in WinRAR.
The deployment of GooseEgg underscores a calculated effort to infiltrate systems not just for initial access but to sustain long-term control by stealing credentials and sensitive information. GooseEgg, typically distributed via batch scripts, demonstrates a clear strategy to enhance the capabilities of compromised networks.
Simultaneously, the cyber landscape has seen an uptick in phishing attacks from the Gamaredon group, with new variants of their GammaLoad malware. This group uses diverse methods to maintain operational momentum, including DNS fluxing across various communication platforms, indicating an escalation in resources devoted to cyber operations.
As organizations increasingly rely on digital systems for operations, understanding the tactics employed by these advanced persistent threat groups is crucial. Businesses must take proactive measures to mitigate risks associated with such vulnerabilities, ensuring they remain vigilant against potential exploitations and maintain robust cybersecurity defenses.
This incident serves as a potent reminder that cybersecurity remains a critical concern for businesses in all sectors, particularly as threat actors evolve their tactics. Organizations should prioritize ongoing security assessments, implement timely updates, and cultivate a culture of cyber vigilance to counter these sophisticated threats.
