Sonatype, a software supply chain security company, this week released the Q2 2025 edition of its Open Source Malware Index, uncovering 16,279 malicious open source packages across major ecosystems including npm and PyPI. This quarter’s count brings the total number of open source malware packages Sonatype has discovered to 845,204. Compared to the end of the same quarter last year, the total volume of malware logged by Sonatype has surged 188%, underscoring the growing sophistication and scale of attacks aimed at developers, software teams, and CI/CD pipelines.
“Attackers are no longer simply experimenting with open source. The numbers are telling us that threat actors have identified data as the most profitable target, and developers as the easiest way in,” said Brian Fox, CTO and co-founder of Sonatype. “Developers and security teams must be vigilant, as threats increasingly hide in plain sight within everyday tools and dependencies.”
Exfiltration remains the most prevalent threat vector, accounting for 55% of all malicious packages discovered. In Q2 alone, more than 4,400 packages were specifically designed to steal sensitive data, including secrets, personally identifiable information (PII), passwords, access tokens, and API keys. These attacks increasingly target the critical intersection of developer tools and production environments, where a single leak can compromise entire systems.
While data exfiltration holds the top spot, Sonatype analysts observed a notable uptick in malware focused on data corruption, with such threats doubling in frequency to represent more than 3% of all malicious packages — more than 400 unique instances in Q2 2025. These packages aim to damage files, inject malicious code, or otherwise sabotage applications and infrastructure.
Malware built for cryptomining comprised 5% of all packages in Q2, marking a slight decline from the previous quarter. This trend may reflect a shift in attacker focus from resource exploitation to more insidious goals such as credential theft and long-term infiltration.
Notably, Lazarus Group, an Advanced Persistent Threat (APT) associated with the North Korean government, was associated with 107 packages discovered by Sonatype in Q2 2025 that collectively have more than 30,050 known downloads. This demonstrates that some of the most sophisticated threat groups in the world are leveraging open source to accomplish cyber espionage, financial cybercrime, and more.
Sonatype’s Open Source Malware Index draws from its proprietary behavioral and automated malware detection systems, actively monitoring and analyzing activity across ecosystems such as npm, PyPI, Maven Central, and more.
The company said its Repository Firewall helped customers prevent 5,354,199 open source malware attacks in Q2 of this year, with 89% of those attacks facing financial services organizations.