CVE-2023-40165
Published: 17 August 2023
Summary
CVE-2023-40165 is a high-severity Improper Input Validation (CWE-20) vulnerability in Rubygems Rubygems.Org. Its CVSS base score is 7.4 (High).
Operationally, ranked at the 33.4th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2023-44772
Vulnerability details
rubygems.org is the Ruby community's primary gem (library) hosting service. Insufficient input validation allowed malicious actors to replace any uploaded gem version that had a platform, version number, or gem name matching `/-\d/`, permanently replacing the legitimate upload in the…
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canonical gem storage bucket, and triggering an immediate CDN purge so that the malicious gem would be served immediately. The maintainers have checked all gems matching the `/-\d/` pattern and can confirm that no unexpected `.gem`s were found. As a result, we believe this vulnerability was _not_ exploited. The easiest way to ensure that a user's applications were not exploited by this vulnerability is to check that all of your downloaded .gems have a checksum that matches the checksum recorded in the RubyGems.org database. RubyGems contributor Maciej Mensfeld wrote a tool to automatically check that all downloaded .gem files match the checksums recorded in the RubyGems.org database. You can use it by running: `bundle add bundler-integrity` followed by `bundle exec bundler-integrity`. Neither this tool nor anything else can prove you were not exploited, but the can assist your investigation by quickly comparing RubyGems API-provided checksums with the checksums of files on your disk. The issue has been patched with improved input validation and the changes are live. No action is required on the part of the user. Users are advised to validate their local gems.
- 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.
Security testing and developer training directly verify and enforce proper input validation, reducing exploitability of injection and malformed-data weaknesses.
Security testing and evaluation at multiple SDLC stages directly detects missing or flawed input validation, with the required remediation process ensuring fixes are applied.
Directly implements checks on information inputs to reject invalid data before processing.
Spam protection mechanisms perform filtering and detection on inbound/outbound messages, directly compensating for missing or weak input validation of unsolicited content.