Fake Claude AI Website Distributes Beagle Windows Malware
Patch: Delete any NOVupdate.exe, NOVupdate.exe.dat, and avk.dll from Startup, block license.claude‑pro.com, and run a full AV scan to remove the Beagle backdoor.
Delete any NOVupdate.exe, NOVupdate.exe.dat, and avk.dll from Startup, block license.claude‑pro.com, and run a full AV scan to remove the Beagle backdoor.
Summary
A counterfeit Claude AI site (claude-pro.com) offers a 505 MB MSI installer called Claude‑Pro‑Relay that, when run, drops three startup files: NOVupdate.exe, NOVupdate.exe.dat, and avk.dll. The installer is a trojanized copy of Claude that launches DonutLoader, which injects the Beagle backdoor into memory and installs a PlugX‑style chain for remote access.
The Beagle backdoor exposes a limited command set—uninstall, cmd, upload, download, mkdir, rename, ls, and rm—and communicates with a command‑and‑control server at license.claude‑pro.com over TCP 443 and UDP 8080, protected by a hard‑coded AES key. The C2 host (8.217.190.58) is registered to Alibaba‑Cloud, and the malware has been linked to prior PlugX activity.
Sophos and Malwarebytes identified the campaign, noting that the presence of NOVupdate files in a system’s Startup folder is a strong indicator of compromise. Users are advised to verify downloads against the official Claude portal, avoid sponsored search results, and remove any NOVupdate or avk.dll files to mitigate the threat.
Key changes
- Fake site hosts 505 MB MSI installer that installs NOVupdate.exe, NOVupdate.exe.dat, and avk.dll into Startup
- Installer triggers DonutLoader which deploys the Beagle backdoor
- Beagle backdoor supports commands: uninstall, cmd, upload, download, mkdir, rename, ls, rm
- C2 uses license.claude‑pro.com over TCP 443/UDP 8080 with AES encryption
- C2 IP 8.217.190.58 on Alibaba‑Cloud
- Backdoor uses XOR decryption and PlugX chain
- Presence of NOVupdate files indicates compromise
- Malware is linked to prior PlugX activity