A complicated backdoor malware marketing campaign has emerged focusing on Home windows customers by means of a weaponized model of SteamCleaner, a official open-source utility designed to wash junk information from the Steam gaming platform.
The malware establishes persistent entry to compromised methods by deploying malicious Node.js scripts that keep steady communication with command-and-control servers, enabling attackers to execute arbitrary instructions remotely.
The risk actors have weaponized the official SteamCleaner instrument, which has not acquired updates since September 2018, by injecting malicious code into the unique supply and distributing it by means of fraudulent web sites posing as unlawful software program repositories.
Customers looking for cracked software program or keygens are redirected to GitHub repositories internet hosting the malware, which is delivered as Setup.exe.
The malicious installer is signed with a legitimate digital certificates from Taiyuan Jiankang Expertise Co., Ltd., lending false legitimacy to the 4.66MB package deal and permitting it to bypass preliminary safety scrutiny.
Upon execution, the malware installs itself within the C:Program FilesSteam Cleaner listing, deploying a number of parts together with Steam Cleaner.exe (3,472KB), configuration information, and batch scripts.
SteamCleaner supply code launched on Github (Supply – ASEC)
ASEC safety researchers recognized that the attackers maintained the unique SteamCleaner performance whereas incorporating subtle anti-sandbox detection mechanisms.
The malware performs in depth environmental checks together with system info evaluation, port enumeration, WMI queries, and course of monitoring.
When a sandboxed surroundings is detected, the malware executes solely the official cleansing performance with out triggering malicious conduct.
The payload supply mechanism depends on encrypted PowerShell instructions embedded inside the malware.
Malware signature and attribute info (Supply – ASEC)
These instructions orchestrate the set up of Node.js on the sufferer’s system and subsequently obtain two distinct malicious scripts from separate command-and-control infrastructure.
Each scripts are registered with the Home windows Activity Scheduler to make sure persistence, executing robotically at system startup and repeating each hour thereafter.
Command-and-Management Communication Protocol
The 2 Node.js scripts set up bidirectional communication channels with their respective C2 servers by means of structured JSON payloads.
When connecting to the C2 infrastructure, the malware transmits complete system reconnaissance knowledge together with OS sort and model, hostname, system structure, and a singular machine identifier derived from the gadget GUID.
The primary script, put in at C:WCM{UUID}UUID and registered as Microsoft/Home windows/WCM/WiFiSpeedScheduler, connects to a number of C2 domains together with rt-guard[.]com, 4tressx[.]com, kuchiku[.]digital, and screenner[.]com.
This script downloads information from attacker-specified URLs and executes them utilizing CMD or PowerShell processes.
The second script operates from C:WindowsSetting{UUID}UUID with the duty title Microsoft/Home windows/Prognosis/Beneficial DiagnosisScheduler, speaking with aginscore[.]com.
This variant employs extra aggressive obfuscation strategies and executes instructions immediately by means of Node[.]js’s native shell execution perform.
The C2 communication happens by means of two major endpoints: /d for receiving instructions and /e for transmitting execution outcomes.
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