Hackers hijacked the npm account of the Axios package, a JavaScript HTTP client with 100M+ weekly downloads, to deliver remote access trojans to Linux, Windows, and macOS systems.

According to reports from software supply chain security and application security companies Endor Labs, Socket, Aikido, and StepSecurity, the threat actor published  on the Node Package Manager (npm) registry two malicious versions of the package

One malicious variant, [email protected], was published today at 00:21 UTC, while the second one, [email protected], emerged less than an hour later, at 01:00 UTC.

The packages were published without the automated OpenID Connect (OIDC) package origin and no matching GitHub commit appeared, which should trigger an alert immediately.

The researchers say that the threat actor gained access to the package after compromising the npm account of Jason Saayman, the main Axios maintainer.

It is unclear how many downstream projects have been impacted by the supply-chain attack during the nearly three-hour exposure window.

Given that the Axios npm package has around 400 million monthly downloads, the number may be significant.

Axios is an HTTP client for JavaScript applications that manages requests between clients, such as browsers or Node.js apps, and servers. Its purpose is to simplify communication via GET, POST, PUT/PATCH, and DELETE requests.

Infection chain

After getting access to the package, the attacker injected a malicious dependency called plain-crypto-js@^4.2.1 into the package.json file and did not alter the Axios code.

The dependency executes a post-install script during the package’s installation, launching an obfuscated dropper (setup.js) that contacts a command-and-control (C2) server to retrieve a next-stage payload based on the detected operating system.

On Windows, the attack mixes VBScript and PowerShell to run a hidden Command Prompt window and execute a malicious script. The malware copies PowerShell to %PROGRAMDATA%\wt.exe to evade detection and achieve persistence across reboots, then downloads and executes a PowerShell script.

On macOS, the malware uses AppleScript to download a binary to /Library/Caches/com.apple.act.mond, mark it as executable, and run it in the background.

On Linux systems, the dropper fetches a Python-based payload stored at ‘/tmp/ld.py’ and executes it in the background with the nohup (no hang up) command.

In all cases, the malware infected the host with a remote access trojan (RAT), allowing attackers to execute commands and maintain persistence on infected systems.

The RAT can retrieve and execute a base64-encoded binary that it writes in a hidden temp file, execute shell commands via /bin/sh or AppleScript, and enumerate directories on the infected host.

After the infection is completed, the dropper deletes itself, removes the modified package.json, and replaces it with a clean copy to make forensic investigations more difficult.

According to researchers at StepSecurity, the Axios supply-chain attack was not opportunistic, but a carefully planned activity, as "the malicious dependency was staged 18 hours in advance."

The fact that different payloads were delivered based on the detected operating system appears to support this theory, along with the self-destruct action for every artifact.

Currently, there is no information about the threat actor behind the Axios supply-chain attack.

Recently, several high-profile supply-chain attacks were claimed by a group known as TeamPCP. The hackers targeted popular open-source software projects like Telnyx, LiteLLM, and Trivy.

However, the compromise of the Axios package does not have the characteristics of a TeamPCP attack, and security researchers couldn’t link it to a specific threat actor.

Users of Axios are recommended to lock at [email protected] and [email protected], which are the last known clean releases of the popular package.

If compromise is confirmed, rotate all credentials and rebuild environments from a known good state.