Key moments
In a significant development for the software community, two malicious versions of the popular JavaScript HTTP client library axios were published on npm on March 31, 2026. The versions, v1.14.1 and v0.30.4, were live for approximately 2 hours and 53 minutes and 2 hours and 15 minutes, respectively, before being removed shortly after discovery.
The malicious versions were published using compromised credentials belonging to a lead maintainer of axios. This breach allowed attackers to inject a malicious package, plain-crypto-js@4.2.1, as a dependency, which was designed to evade detection by appearing legitimate. The attack was pre-staged across roughly 18 hours before the malicious versions went live, indicating a high level of planning and sophistication.
According to reports, the attack involved a cross-platform Remote Access Trojan (RAT) targeting macOS, Windows, and Linux environments. The RAT dropper executes a postinstall script that contacts a command-and-control server, posing a serious risk to users who inadvertently installed the malicious versions. The attack resulted in observed execution in 3% of affected environments, raising alarms within the developer community.
axios is the most popular JavaScript HTTP client library, boasting over 100 million weekly downloads and being utilized in approximately 80% of cloud and code environments. This widespread usage makes the software an attractive target for cybercriminals. The incident underscores the vulnerabilities inherent in the software supply chain and the potential for widespread impact when such vulnerabilities are exploited.
StepSecurity, the organization that detected the attack, utilized its AI Package Analyst and Harden-Runner tools to identify the malicious activity. The detection was crucial, as it allowed for a swift response to mitigate potential damage. The organization has advised all users to audit their environments for any potential execution of the compromised versions.
Experts have noted that “there are zero lines of malicious code inside axios itself, and that’s exactly what makes this attack so dangerous.” This highlights the complexity of supply chain attacks, where the integrity of the main software is not compromised, but rather the dependencies are manipulated to introduce vulnerabilities.
As the community grapples with the implications of this attack, organizations are urged to remain vigilant. The connection to the maintainer’s account was marked as anomalous, as it had never appeared in any prior workflow run, further emphasizing the need for enhanced security measures in software development practices.
While the immediate threat has been addressed with the removal of the malicious packages, the incident serves as a stark reminder of the ongoing risks associated with software supply chains. Organizations must prioritize security audits and implement robust monitoring systems to safeguard against similar attacks in the future.
