The threat actors behind the zero-day exploitation of a recently-patched security vulnerability in Microsoft Windows have been found to deliver two new backdoors called SilentPrism and DarkWisp. The activity has been attributed to a suspected Russian hacking group called Water Gamayun, which is also known as EncryptHub and LARVA-208. "The threat actor deploys payloads primarily by means of malicious provisioning packages, signed .msi files, and Windows MSC files, using techniques like the IntelliJ runnerw.exe for command execution," Trend Micro researchers Aliakbar Zahravi and Ahmed Mohamed Ibrahim said in a follow-up analysis published last week. Water Gamayun has been linked to the active exploitation of CVE-2025-26633 (aka MSC EvilTwin), a vulnerability in the Microsoft Management Console (MMC) framework, to execute malware by means of a rogue Microsoft Console (.msc) file.

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