xHunt APT Group Spies on Kuwait, Leveraging Microsoft Exchange, IIS, and Custom Backdoors
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Key Takeaways
- Targeted operations: xHunt continues its cyber espionage, primarily targeting shipping, transportation, and government entities in Kuwait.
- Custom toolkit: The group uses a unique, evolving set of custom backdoors, often named after characters from the anime series "Hunter x Hunter."
- Exchange server exploitation: A key tactic involves compromising MS Exchange servers to establish persistence and use email drafts for C2communications.
The xHunt cyberespionage group continues to execute sophisticated, persistent attacks, with a primary focus on entities in Kuwait. First observed in 2018, these xHunt APT operations are characterized by a highly targeted approach and a distinctive, custom-built malware toolkit.Â
The Evolving Malware Arsenal
The group has demonstrated proficiency in compromising web-facing servers, particularly Microsoft Exchange and IIS, to gain initial access, the latest report from Picus Security said.Â
A hallmark of xHunt's campaigns is its use of custom PowerShell backdoors, including Hisoka, Sakabota (which provides a Mimikatz binary), Netero, and Killua, and PowerShell-based backdoors TriFive, Snugy (a CASHY200 variant), and BumbleBee.
For credential access, they relied on:
- Brute forcing – using the popular password cracking tool THC-Hydra to brute-force logins for the Remote Desktop Protocol (RDP).
- Application layer protocol – using previously stolen credentials to access email accounts.
- Protocol tunneling – using established SSH tunnels to interact with BumbleBee on internal IIS web servers that were not directly internet-accessible.
- Obfuscated infrastructure – routing access through PIA VPN infrastructure.
The Hisoka and TriFive backdoors communicate via EWS by reading and writing base64-encoded commands in the Drafts or Deleted Items folders of a compromised user's mailbox. This method avoids traditional network-based C2 traffic, making detection more challenging.Â
The group:
- Uses tools like TriFive and Snugy to maintain persistence, often executed via scheduled tasks to evade detection.Â
- Exploits Exchange Web Services (EWS) to facilitate stealthy command-and-control (C2) communications.Â
- Uses the BumbleBee webshell for direct command execution and SSH tunnels for lateral movement within compromised networks.
One of its more novel techniques involved a watering hole attack on a Kuwaiti government website to passively harvest NTLM hashes from visitors, showcasing the group's patience and ingenuity.
Cybersecurity Implications of Advanced APT Tactics
The sustained cyber-espionage in Kuwait by xHunt highlights the increasing sophistication of state-sponsored threat actors.Â
For organizations, particularly those in critical sectors, this reinforces the importance of securing internet-facing applications, implementing robust email security protocols, and monitoring for unusual activity within Exchange environments.Â
Last month, the Iran-linked MuddyWater group launched the Phoenix backdoor espionage campaign, leveraging compromised email accounts, and the PassiveNeuron cyberespionage campaign targeted global organizations with custom APT implants.
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