Back Bleepingcomputer Hackers abuse Notepad++ plugins to stealthily install malware
Ukraine's CERT has uncovered attacks distributing an archive containing the legitimate Notepad++ application and a malicious utility called LunchPoke disguised as a plugin to establish persistence.
The campaign has been attributed to a threat cluster tracked as UAC-0099, which primarily targets organizations in Ukraine and has previously been linked to providing initial access for attacks carried out by APT44 , also known as Sandworm.
The attackers do not exploit any vulnerability or a supply-chain compromise impacting the popular software.
CERT-UA observed that UAC-0099 changed their modus operandi recently and now delivers a ZIP archive with a VBS script disguised as a PDF document. When launched, the PDF retrieves another compressed file named Evernote.zip.
The second archive contains a complete copy of the legitimate editor Notepad++ version 8.8.3, a malicious plugin (NppExport.dll), a password-protected archive (updater.rar), and the legitimate WinRAR executable.
The VBS script installs the package into a randomly named directory, launches Notepad++, and then loads the malicious NppExport.dll via the application’s normal plugin-loading mechanism.
CERT-UA explains that this DLL is LunchPoke, a tool that creates a scheduled task on Windows and extracts the contents of the RAR file, including RemoteLibUpdater.exe and InitTest.dll .
The executable in the RAR file is BurnyBear, a loader for the DLL file that is the MatchBoil V2 malware loader.
BurnyBear also features a fallback mechanism in case launching RemoteLibUpdater.exe fails, triggering a resource exhaustion attack targeting the host’s RAM and CPU.
The latter creates another scheduled task, updates its configuration and command-and-control (C2) address, and then uses WinRAR to extract downloaded programs.
CERT-UA does not mention the final payloads delivered in the observed attacks, the purpose of the campaign, or the targeted organizations.
The researchers mention CVE-2025-56383 , a DLL hijacking flaw in Notepad++ v8.8.3, the exact version used in these attacks, but note that the Notepad++ team has disputed this issue, claiming that plugin loading is standard functionality.
CERT-UA advises system administrators to update Notepad++ to version 8.9.7, 7-Zip to version 26.02, and WinRAR to version 7.23, to prevent hackers from exploiting known flaws in existing products and enabling stealthy attacks.
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