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JWS and JWT signature validation vulnerability with special characters

High severity GitHub Reviewed Published Jun 23, 2022 in kjur/jsrsasign • Updated Jan 27, 2023

Package

npm jsrsasign (npm)

Affected versions

>= 4.8.0, < 10.5.25

Patched versions

10.5.25

Description

Impact

Jsrsasign supports JWS(JSON Web Signatures) and JWT(JSON Web Token) validation. However JWS or JWT signature with non Base64URL encoding special characters or number escaped characters may be validated as valid by mistake.

For example, even if a string of non Base64URL encoding characters such as !@$% or \11 is inserted into a valid JWS or JWT signature value string, it will still be a valid JWS or JWT signature by mistake.

When jsrsasign's JWS or JWT validation is used in OpenID connect or OAuth2, this vulnerability will affect to authentication or authorization.

By our internal assessment, CVSS 3.1 score will be 8.6.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:H/A:N

Patches

Users validate JWS or JWT signatures should upgrade to 10.5.25.

Workarounds

Validate JWS or JWT signature if it has Base64URL and dot safe string before
executing JWS.verify() or JWS.verifyJWT() method.

ACKNOWLEDGEMENT

Thanks to Adi Malyanker and Or David for this vulnerability report. Also thanks for Snyk security team for this coordination.

References

https://github.com/kjur/jsrsasign/releases/tag/10.5.25
GHSA-3fvg-4v2m-98jf kjur's advisories
GHSA-3fvg-4v2m-98jf github advisories
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2022-25898
https://kjur.github.io/jsrsasign/api/symbols/KJUR.jws.JWS.html#.verifyJWT
https://kjur.github.io/jsrsasign/api/symbols/KJUR.jws.JWS.html#.verify
https://kjur.github.io/jsrsasign/api/symbols/global__.html#.isBase64URLDot
https://github.com/kjur/jsrsasign/wiki/Tutorial-for-JWS-verification
https://github.com/kjur/jsrsasign/wiki/Tutorial-for-JWT-verification
https://security.snyk.io/vuln/SNYK-JS-JSRSASIGN-2869122

References

@kjur kjur published to kjur/jsrsasign Jun 23, 2022
Published to the GitHub Advisory Database Jun 25, 2022
Reviewed Jun 25, 2022
Published by the National Vulnerability Database Jul 1, 2022
Last updated Jan 27, 2023

Severity

High

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Changed
Confidentiality
None
Integrity
High
Availability
None

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:H/A:N

EPSS score

1.298%
(86th percentile)

Weaknesses

CVE ID

CVE-2022-25898

GHSA ID

GHSA-3fvg-4v2m-98jf

Source code

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