This is a cross-post of the official security advisory. The official advisory contains a signed version with our PGP key, as well.

The Rust Security Response WG and the crates.io team were notified on 2022-05-02 of the existence of the malicious crate rustdecimal, which contained malware. The crate name was intentionally similar to the name of the popular rust_decimal crate, hoping that potential victims would misspell its name (an attack called "typosquatting").

To protect the security of the ecosystem, the crates.io team permanently removed the crate from the registry as soon as it was made aware of the malware. An analysis of all the crates on crates.io was also performed, and no other crate with similar code patterns was found.

Keep in mind that the rust_decimal crate was not compromised, and it is still safe to use.

Analysis of the crate

The crate had less than 500 downloads since its first release on 2022-03-25, and no crates on the crates.io registry depended on it.

The crate contained identical source code and functionality as the legit rust_decimal crate, except for the Decimal::new function.

When the function was called, it checked whether the GITLAB_CI environment variable was set, and if so it downloaded a binary payload into /tmp/git-updater.bin and executed it. The binary payload supported both Linux and macOS, but not Windows.

An analysis of the binary payload was not possible, as the download URL didn't work anymore when the analysis was performed.

Recommendations

If your project or organization is running GitLab CI, we strongly recommend checking whether your project or one of its dependencies depended on the rustdecimal crate, starting from 2022-03-25. If you notice a dependency on that crate, you should consider your CI environment to be compromised.

In general, we recommend regularly auditing your dependencies, and only depending on crates whose author you trust. If you notice any suspicious behavior in a crate's source code please follow the Rust security policy and report it to the Rust Security Response WG.

Acknowledgements

We want to thank GitHub user @safinaskar for identifying the malicious crate in this GitHub issue.