Steam

BrokenPipe PoC Exploits Steam Client Service for Silent SYSTEM Privilege Escalation on Windows

A new proof-of-concept named BrokenPipe demonstrates how a standard Windows user can escalate privileges to NT AUTHORITY\SYSTEM through the Steam Client Service without requiring administrator credentials or triggering a UAC prompt. The vulnerability stems from insufficient signature validation in VDF installation scripts processed by steamservice.exe, allowing an attacker to control the execution path of a malicious script. The issue affects Steam version 10.96.30.42 on both Windows 10 and Windows 11, though no public CVE has been assigned yet. Valve was notified of the flaw in March, several months prior to public disclosure. The attack is strictly local and requires initial code execution under a standard user account, making it relevant for shared or corporate environments. Security teams are advised to inventory Steam installations, apply application allowlisting, and monitor for anomalous SYSTEM-level processes linked to the service while awaiting an official patch.

TELEPUZ Malware Spreads via ClickFix Social Engineering, Targets Windows with Modular Capabilities and Resilient C2 Infrastructure

Since late April 2026, compromised websites have been distributing the new modular malware TELEPUZ through the ClickFix scheme. Attackers replace standard browser error fixes with instructions that trick users into pasting and executing a PowerShell command from the clipboard, which then downloads an intermediate loader, the Vidar infostealer, and finally TELEPUZ via rundll32.exe. The malware performs extensive environment checks to avoid sandboxes and debuggers before disabling Windows security features, escalating privileges, and persisting as a service inside svchost.exe. For command-and-control, TELEPUZ relies on WebSocket connections with multiple fallback mechanisms, including encrypted links stored in Telegram profiles, Steam accounts, DNS records, and a Polygon smart contract. It offers a wide range of capabilities such as file manipulation, keylogging, screenshot capture, process management, cookie theft from Chromium browsers, and arbitrary JavaScript execution in both Chromium and Firefox. Researchers at Elastic assess TELEPUZ as a malware-as-a-service offering still in early development, evidenced by a limited number of C2 domains yet frequent daily builds and rapid updates hosted on compromised sites in Brazil and India.