As organisations increasingly rely on third-party packages within their development workflows, threat actors are exploiting vulnerabilities in the OSS ecosystem to propagate malicious code and exfiltrate sensitive data.
In the second quarter of 2025, FortiGuard Labs conducted a comprehensive analysis of over 1.4 million Node Package Manager (NPM) and 400,000 Python Package Index (PyPI) packages.
The findings revealed a substantial number of malicious packages, with data exfiltration identified as a common tactic employed by attackers. This underscores the persistent nature of supply chain threats within the OSS landscape.
Key insights from the report indicate that many malicious packages are designed to minimise their code footprint and avoid detection.
For instance, the analysis confirmed that a high percentage of these packages feature low file counts, lack linked repositories, and utilise install scripts to execute malicious actions silently during installation.
Additionally, an increase in obfuscation techniques was noted compared to previous quarters.
Several examples from Q2 2025 exemplify the tactics used by malware authors. Among the malicious PyPI packages identified were simple-mali-pkg-0.1.0 and solana-sdkpy-1.2.5, which employed install scripts and encrypted code to conceal their true intentions. For example, in simple-mali-pkg-0.1.0, the mali.py file executed suspicious code that ultimately aimed to steal credentials and digital wallets.
Similarly, the NPM package postcss-theme-vars-7.0.7 demonstrated malicious behaviour through obfuscated code that targeted sensitive information, including browser profiles and saved passwords. This package highlighted the ongoing persistence of data theft campaigns within the OSS ecosystem, as the threat evolved with variations in its implementation.
The analysis reinforces previous observations that the exploitation of OSS repositories for malware distribution remains a significant threat. While the core tactics of attackers have not evolved dramatically, their reliance on established techniques—such as minimising file counts and employing obfuscation—continues to pose serious risks.
To mitigate these threats, organisations are urged to enhance their awareness and understanding of OSS supply chain vulnerabilities.
Strengthening defences and implementing continuous monitoring practices are critical steps toward safeguarding against potential risks associated with malicious packages in open-source environments.
As the OSS landscape continues to expand, so too does the attack surface for supply chain threats, necessitating vigilance and proactive measures.
