PT-2019-8900 · Yarnpkg · Yarnpkg

Marcus Brinkmann · Published 2019-05-16 · Updated 2019-05-21 · CVE-2018-12556

Positive Technologies (AI Summary)

CVSS v3.1

5.9

Medium

Base vector

AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N

Name of the Vulnerable Software and Affected Versions yarnpkg/website versions prior to 2018-06-05

Description The issue lies in the signature verification routine of the install.sh script, which only checks if a yarn release is signed by any key in the user's local keyring. This does not ensure the release is signed by the official yarn release key, allowing remote attackers to sign tampered packages with their own key.

Recommendations For versions prior to 2018-06-05, update to a version released after 2018-06-05 to ensure the signature verification routine correctly pins the signature to the yarn release key.

Fix

Improper Verification of Cryptographic Signature

Weakness Enumeration

CWE-347

Related Identifiers

CVE-2018-12556

Affected Products

Yarnpkg

References · 12

• https://ubuntu.com/security/CVE-2018-12556 · Vendor Advisory
• https://osv.dev/vulnerability/CVE-2018-12556 · Vendor Advisory
• https://cve.org/CVERecord?id=CVE-2018-12556 · Security Note
• https://nvd.nist.gov/vuln/detail/CVE-2018-12556 · Security Note
• https://osv.dev/vulnerability/UBUNTU-CVE-2018-12556 · Vendor Advisory
• https://github.com/yarnpkg/website/commits/master · Note
• https://github.com/RUB-NDS/Johnny-You-Are-Fired · Note
• https://github.com/RUB-NDS/Johnny-You-Are-Fired/blob/master/paper/johnny-fired.pdf · Note
• https://neopg.io/blog/yarn-signature-bypass · Note
• http://packetstormsecurity.com/files/152703/Johnny-You-Are-Fired.html · Note
• http://seclists.org/fulldisclosure/2019/Apr/38 · Note
• https://openwall.com/lists/oss-security/2019/04/30/4 · Note