CVE-2020-5268 Information

Description

In Saml2 Authentication Services for ASP.NET versions before 1.0.2 and between 2.0.0 and 2.6.0 there is a vulnerability in how tokens are validated in some cases. Saml2 tokens are usually used as bearer tokens - a caller that presents a token is assumed to be the subject of the token. There is also support in the Saml2 protocol for issuing tokens that is tied to a subject through other means e.g. holder-of-key where possession of a private key must be proved. The Sustainsys.Saml2 library incorrectly treats all incoming tokens as bearer tokens even though they have another subject confirmation method specified. This could be used by an attacker that could get access to Saml2 tokens with another subject confirmation method than bearer. The attacker could then use such a token to create a log in session. This vulnerability is patched in versions 1.0.2 and 2.7.0.

CVSS Vector

CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:N

Reference

https://github.com/Sustainsys/Saml2/commit/e58e0a1aff2b1ead6aca080b7cdced55ee6d5241 https://github.com/Sustainsys/Saml2/issues/712 https://github.com/Sustainsys/Saml2/security/advisories/GHSA-9475-xg6m-j7pw https://www.nuget.org/packages/Sustainsys.Saml2/

Attack Complexity

LOW

Privileges Required

LOW

User Interaction Required

LOW

Scope

REQUIRED

Confidentiality Impact

UNCHANGED

Integrity Impact

HIGH

Availability Impact

HIGH

Base Score

NONE

Base Severity

7.3