A new supply chain attack has been observed targeting Azure developers through the use of over 218 malicious NPM packages. The goal of these malicious packages appears to be to steal personal identifiable information on the developer’s system where it is executed.

The attack works through typosquatting, which occurs when threat actors publish malicious packages with names mimicking legitimate libraries in an effort to trick users into installing them. In this case, the threat actor created dozens of malicious counterparts with the same name as their existing @azure scope packages but without the scope name in the NPM software registry. For example, if users were to attempt to install the legitimate @azure/core-tracing package, but upon installation omitted the @azure prefix, they would end up installing the malicious package instead. Each malicious package was uploaded using a unique username to avoid raising suspicion and used high version numbers to attempt to carry out a dependency confusion attack. This attack occurs when the build process of an application automatically pulls a malicious version of a private module into it, due to there being a higher version of the software available that is deemed the “latest” version for that package.

When executed, the malicious packages in question were seen listing directories and gathering information on the user’s current directory and IP addresses related to network interfaces and DNS servers. All of this information was then exfiltrated to a hardcoded remote server. All 218 packages have been removed from the NPM registry, with each one having been downloaded around 50 times prior to removal.