CVE-2022-36113
Published: 14 September 2022
Summary
CVE-2022-36113 is a medium-severity Path Traversal (CWE-22) vulnerability in Rust-Lang Cargo. Its CVSS base score is 4.6 (Medium).
Operationally, ranked in the top 7.2% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog.
Deeper analysis
Cargo is a package manager for the Rust programming language that extracts package source code into the user's ~/.cargo directory after download. The vulnerability, present in all versions prior to the fix, allows a package to include a .cargo-ok symbolic link; upon successful extraction Cargo writes the string "ok" through that link, overwriting the first two bytes of an arbitrary target file on disk. The issue is tracked as CVE-2022-36113 (CWE-22/CWE-59) with a CVSS 3.1 score of 4.6 and affects the extraction logic rather than build-time execution primitives.
An attacker who can supply a package from an alternate registry can therefore corrupt a chosen file on a victim's machine when the package is fetched and extracted. Because crates.io already rejects such packages server-side, exploitation requires the victim to depend on a malicious crate from a third-party registry; the resulting damage is limited to partial file corruption and is harder to attribute than actions performed by build scripts or procedural macros, which Cargo intentionally permits.
The official advisory states that Rust 1.64 (released 22 September 2022) contains the correction and that back-port patches for 1.63.0 are available in the wg-security-response repository. It recommends that users of alternate registries continue to vet dependencies carefully, noting that the underlying design of Cargo still allows arbitrary code execution via build scripts regardless of this fix. The EPSS score has remained flat at 0.0894 with no observed increase after disclosure.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2022-6934
Vulnerability details
Cargo is a package manager for the rust programming language. After a package is downloaded, Cargo extracts its source code in the ~/.cargo folder on disk, making it available to the Rust projects it builds. To record when an extraction…
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is successful, Cargo writes "ok" to the .cargo-ok file at the root of the extracted source code once it extracted all the files. It was discovered that Cargo allowed packages to contain a .cargo-ok symbolic link, which Cargo would extract. Then, when Cargo attempted to write "ok" into .cargo-ok, it would actually replace the first two bytes of the file the symlink pointed to with ok. This would allow an attacker to corrupt one file on the machine using Cargo to extract the package. Note that by design Cargo allows code execution at build time, due to build scripts and procedural macros. The vulnerabilities in this advisory allow performing a subset of the possible damage in a harder to track down way. Your dependencies must still be trusted if you want to be protected from attacks, as it's possible to perform the same attacks with build scripts and procedural macros. The vulnerability is present in all versions of Cargo. Rust 1.64, to be released on September 22nd, will include a fix for it. Since the vulnerability is just a more limited way to accomplish what a malicious build scripts or procedural macros can do, we decided not to publish Rust point releases backporting the security fix. Patch files are available for Rust 1.63.0 are available in the wg-security-response repository for people building their own toolchain. Mitigations We recommend users of alternate registries to exercise care in which package they download, by only including trusted dependencies in their projects. Please note that even with these vulnerabilities fixed, by design Cargo allows arbitrary code execution at build time thanks to build scripts and procedural macros: a malicious dependency will be able to cause damage regardless of these vulnerabilities. crates.io implemented server-side checks to reject these kinds of packages years ago, and there are no packages on crates.io exploiting these vulnerabilities. crates.io users still need to exercise care in choosing their dependencies though, as remote code execution is allowed by design there as well.
- CWE(s)
Related Threats
No named actor attribution yet. ATT&CK technique mapping in progress for this CVE.
Affected Assets
Mitigating Controls
Likely Mitigating Controls AI
Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.
Validates pathnames and filenames to prevent traversal outside intended directories.