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kjur/jsrsasign · Security

RSA-PSS signature validation vulnerability by prepending zeros in jsrsasign

GHSA ID
GHSA-q3gh-5r98-j4h3
CVE ID
CVE-2020-14968
Severity
critical
Published
Updated
CVSS
9.8 · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CVSS v3
9.8 · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Description

Impact

Jsrsasign can verify RSA-PSS signature which value can expressed as BigInteger. When there is a valid RSA-PSS signature value, this vulnerability is also accept value with prepending zeros as a valid signature.

  • If you are not use RSA-PSS signature validation, this vulnerability is not affected.
  • Risk to accept a forged or crafted message to be signed is low.
  • Risk to raise memory corruption is low since jsrsasign uses BigInteger class.

Patches

Users using RSA-PSS signature validation should upgrade to 8.0.17.

Workarounds

Reject RSA-PSS signatures with unnecessary prepending zeros.

References

https://github.com/kjur/jsrsasign/security/advisories/GHSA-q3gh-5r98-j4h3 https://github.com/kjur/jsrsasign/issues/438 https://nvd.nist.gov/vuln/detail/CVE-2020-14968 https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2020-14968 https://vuldb.com/?id.157125 https://kjur.github.io/jsrsasign/api/symbols/RSAKey.html#.verifyWithMessageHashPSS

CWEs

  • CWE-119 · Improper Restriction of Operations within the Bounds of a Memory Buffer

References