VIPERTUNNEL Python Backdoor Hidden in Fake DLL, Obfuscated Loader Chain

Gbhackers •Mayura Kathir • April 13, 2026

Hackers are abusing a stealthy Python backdoor called VIPERTUNNEL, hiding it behind a fake DLL file and a multi‑stage obfuscated loader to quietly tunnel traffic out of victim networks. A review of persistence mechanisms revealed a sitecustomize.py file in C:\ProgramData\cp49s\Lib\. This special Python module auto‑loads at interpreter startup and can silently run code without command‑line input. This script used ctypes to […]

The full story

This article is one source in a clustered incident — the cluster page carries the summary, timeline and every other outlet covering it.

VIPERTUNNEL Python Backdoor Exploits Fake DLL for Stealth Access A Python backdoor named VIPERTUNNEL is being utilized by hackers to infiltrate enterprise networks. The malware is concealed within a fake DLL file and employs a multi-stage obfuscated loader to evade detection. Once installed, VIPERTUNNEL establishes a SOCKS5 proxy tunnel to a remote command-and-control server, allowing attackers to maintain persistent access to compromised systems. The backdoor's persistence is achieved through a sitecustomize.py file located in C:\ProgramData\cp49s\Lib\, which executes automatically at Python interpreter startup. This method enables the execution of malicious code without user interaction. Organizations are urged to be vigilant as the malware targets enterprise environments, posing a significant risk to network security. Current status indicates ongoing exploitation of this backdoor, with no specific mitigation measures detailed in the articles. 3 sources 65

Extracted Entities

VIPERTUNNEL Python Backdoor Hidden in Fake DLL, Obfuscated Loader Chain

The full story

Extracted Entities

Attack Types (1)

Malware (1)

MITRE ATT&CK (2)

Tools (1)