PT-2020-18358 · Sustainsys+1 · Sustainsys.Saml2+2

Anders Abel

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Published

2020-04-21

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Updated

2020-05-06

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CVE-2020-5268

CVSS v3.1

6.5

Medium

VectorAV:N/AC:H/PR:L/UI:R/S:C/C:H/I:L/A:N
Name of the Vulnerable Software and Affected Versions Saml2 Authentication Services for ASP.NET versions before 1.0.2 Saml2 Authentication Services for ASP.NET versions 2.0.0 through 2.6.0
Description 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. 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.
Recommendations For versions before 1.0.2, update to version 1.0.2 to resolve the issue. For versions 2.0.0 through 2.6.0, update to version 2.7.0 to resolve the issue. As a temporary workaround, ensure that any IdentityProvider trusted by the Sustainsys.Saml2 SP only issues bearer tokens if the audience matches the Sustainsys.Saml2 SP.

Fix

Improper Authentication

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Weakness Enumeration

Related Identifiers

CVE-2020-5268
GHSA-9475-XG6M-J7PW

Affected Products

Asp.Net
Saml2 Authentication Services For Asp.Net
Sustainsys.Saml2