Cybersecurity researchers have identified malicious packages on the open-source Python Package Index (PyPI) repository that deliver an information stealing malware called WhiteSnake Stealer on Windows systems.
The malware-laced packages are named nigpal, figflix, telerer, seGMM, fbdebug, sGMM, myGens, NewGends, and TestLibs111. They have been uploaded by a threat actor named "WS."
"These packages incorporate Base64-encoded source code of PE or other Python scripts within their setup.py files," Fortinet FortiGuard Labs said in an analysis published last week.
"Depending on the victim devices' operating system, the final malicious payload is dropped and executed when these Python packages are installed."
While Windows systems are infected with WhiteSnake Stealer, compromised Linux hosts are served a Python script designed to harvest information. The activity, which predominantly targets Windows users, overlaps with a prior campaign that JFrog and Checkmarx disclosed last year.
"The Windows-specific payload was identified as a variant of the [...] WhiteSnake malware, which has an Anti-VM mechanism, communicates with a C&C server using the Tor protocol, and is capable of stealing information from the victim and executing commands," JFrog noted in April 2023.
It's also designed to capture data from web browsers, cryptocurrency wallets, and apps like WinSCP, CoreFTP, Windscribe, Filezilla, AzireVPN, Snowflake, Steam, Discord, Signal, and Telegram.
Checkmarx is tracking the threat actor behind the campaign under the moniker PYTA31, stating the end goal is to exfiltrate sensitive and particularly crypto wallet data from the target machines.
Some of the newly published rogue packages have also been observed incorporating clipper functionality to overwrite clipboard content with attacker-owned wallet addresses to carry out unauthorized transactions. A few others have been configured to steal data from browsers, applications, and crypto services.
Fortinet said the finding "demonstrates the ability of a single malware author to disseminate numerous info-stealing malware packages into the PyPI library over time, each featuring distinct payload intricacies."
The disclosure comes as ReversingLabs discovered two malicious packages on the npm package registry that have been found to leverage GitHub to store Base64-encrypted SSH keys stolen from developer systems on which they were installed.
