Fake Notepad++ Plugin Delivers MATCHBOIL.V2 in UAC-0099 Attacks

The Computer Emergency Response Team of Ukraine (CERT-UA) has warned of a new campaign that involves the use of a malicious program that's dressed up as a Notepad++ plugin to compromise Windows systems. The activity has been attributed by the agency to a threat cluster it tracks as UAC-0099, a Russia-aligned group that has previously observed weaponizing security flaws in WinRAR software to

According to CERT-UA, the Russia-aligned threat cluster UAC-0099 is abusing the Notepad++ plugin loading mechanism, delivering a fake plugin that installs LunchPoke, which then deploys BurnyBear and a modified MatchBoil V2 implant via InitTest.dll.[1][2] The campaign relies on phishing emails, ZIP archives, double-extension VBS files, and persistence via scheduled tasks to compromise Windows systems.[1][2] From a RealGround perspective, this illustrates how adversaries can weaponize trusted extensibility mechanisms and third-party components, a pattern directly analogous to AI model/plugin ecosystems and agent toolchains. Organizations should extend SBOM and supply-chain controls to AI-related plugins, extensions, and tools, verifying provenance, monitoring for unauthorized DLLs or agent tools, and integrating continuous code-signing and dependency integrity checks into their AI development and deployment pipelines.