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Security Advisories: MDE2OlNlY3VyaXR5QWR2aXNvcnlHSFNBLTk0NzUteGc2bS1qN3B3
Subject Confirmation Method not validated in Saml2 Authentication Services for ASP.NET
Impact
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 tocken to create a log in session.
Patches
Version 1.0.2 and 2.7.0 are patched.
Workarounds
Ensure that any IdentityProvider trusted by the Sustainsys.Saml2 SP only issues bearer tokens if the audience matches the Sustainsys.Saml2 SP.
For more information
If you have any questions or comments about this advisory:
- Comment on #103
- Email us at [email protected] if you think that there are further security issues.
JSON: https://advisories.ecosyste.ms/api/v1/advisories/MDE2OlNlY3VyaXR5QWR2aXNvcnlHSFNBLTk0NzUteGc2bS1qN3B3
Source: GitHub Advisory Database
Origin: Unspecified
Severity: Moderate
Classification: General
Published: over 4 years ago
Updated: almost 2 years ago
CVSS Score: 6.5
CVSS vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:H/I:L/A:N
EPSS Percentage: 0.00131
EPSS Percentile: 0.48737
Identifiers: GHSA-9475-xg6m-j7pw, CVE-2020-5268
References:
- https://github.com/Sustainsys/Saml2/security/advisories/GHSA-9475-xg6m-j7pw
- https://github.com/Sustainsys/Saml2/issues/712
- https://github.com/Sustainsys/Saml2/commit/e58e0a1aff2b1ead6aca080b7cdced55ee6d5241
- https://www.nuget.org/packages/Sustainsys.Saml2/
- https://nvd.nist.gov/vuln/detail/CVE-2020-5268
- https://github.com/advisories/GHSA-9475-xg6m-j7pw
Blast Radius: 1.0
Affected Packages
nuget:Sustainsys.Saml2
Dependent packages: 7Dependent repositories: 0
Downloads: 8,502,554 total
Affected Version Ranges: >= 2.0.0, < 2.7.0, < 1.0.2
Fixed in: 2.7.0, 1.0.2
All affected versions: 0.23.0, 0.24.0, 1.0.0, 1.0.1, 2.0.0, 2.1.0, 2.2.0, 2.3.0, 2.4.0, 2.5.0, 2.6.0
All unaffected versions: 1.0.2, 1.0.3, 2.7.0, 2.8.0, 2.9.0, 2.9.1, 2.9.2, 2.10.0