CVE-2020-5268 Detail

Current 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.


View Analysis Description

Severity



CVSS 3.x Severity and Metrics:

NIST CVSS score
NIST: NVD
Base Score:  7.3 HIGH
Vector:  CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:N

Nist CVSS score does not match with CNA score
CNA:  GitHub, Inc.
Base Score:  6.5 MEDIUM
Vector:  CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:H/I:L/A:N


NVD Analysts use publicly available information to associate vector strings and CVSS scores. We also display any CVSS information provided within the CVE List from the CNA.

Note: It is possible that the NVD CVSS may not match that of the CNA. The most common reason for this is that publicly available information does not provide sufficient detail or that information simply was not available at the time the CVSS vector string was assigned.

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Hyperlink Resource
https://github.com/Sustainsys/Saml2/commit/e58e0a1aff2b1ead6aca080b7cdced55ee6d5241 Patch  Third Party Advisory 
https://github.com/Sustainsys/Saml2/issues/712 Third Party Advisory 
https://github.com/Sustainsys/Saml2/security/advisories/GHSA-9475-xg6m-j7pw Mitigation  Third Party Advisory 
https://www.nuget.org/packages/Sustainsys.Saml2/ Third Party Advisory 

Weakness Enumeration

CWE-ID CWE Name Source
CWE-287 Improper Authentication cwe source acceptance level NIST  
CWE-303 Incorrect Implementation of Authentication Algorithm Reference acceptance level GitHub, Inc.  

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Change History

4 change records found show changes

Quick Info

CVE Dictionary Entry:
CVE-2020-5268
NVD Published Date:
04/21/2020
NVD Last Modified:
05/06/2020
Source:
GitHub, Inc.