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kjur/jsrsasign · Security

RSA PKCS#1 decryption vulnerability with prepending zeros in jsrsasign

GHSA ID
GHSA-xxxq-chmp-67g4
CVE ID
CVE-2020-14967
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 supports RSA PKCS#1 v1.5 (i.e. RSAES-PKCS1-v1_5) and RSA-OAEP encryption and decryption. Its encrypted message is represented as BigInteger. When there is a valid encrypted message, a crafted message with prepending zeros can be decrypted by this vulnerability.

  • If you don't use RSA PKCS1-v1_5 or RSA-OAEP decryption, this vulnerability is not affected.
  • Risk to forge contents of encrypted message is very low.
  • Risk to raise memory corruption is low since jsrsasign uses BigInteger class.

Patches

Users using RSA PKCS1-v1_5 or RSA-OAEP decryption should upgrade to 8.0.18.

Workarounds

Reject RSA PKCS1-v1_5 or RSA-OAEP encrypted message with unnecessary prepending zeros.

References

https://nvd.nist.gov/vuln/detail/CVE-2020-14967 https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2020-14967 https://vuldb.com/?id.157124 https://kjur.github.io/jsrsasign/api/symbols/KJUR.crypto.Cipher.html#.decrypt https://github.com/kjur/jsrsasign/issues/439

CWEs

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

References