Batten Down Your Packages: Mitigation Guidance for Supply Chain Compromise

Open source software supply chain compromises (attacks where malicious code is inserted into popular software libraries) have grown significantly in 2025-2026, with threat actors targeting repositories like PyPI, npm, and Docker Hub to distribute malware at scale. These attacks are easier to execute than traditional supply chain compromises but are discovered more quickly once deployed. Google's Threat Intelligence Group and Mandiant tracked multiple large-scale campaigns, including one by UNC6780 that used stolen credentials and another by MIDNIGHT NEPTUNE that compromised the axios package to deploy backdoors (hidden remote access tools).