// For flags

CVE-2020-5268

Subject Confirmation Method not validated in Saml2 Authentication Services for ASP.NET

Severity Score

7.3
*CVSS v3.1

Exploit Likelihood

*EPSS

Affected Versions

*CPE

Public Exploits

0
*Multiple Sources

Exploited in Wild

-
*KEV

Decision

-
*SSVC
Descriptions

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.

En Saml2 Authentication Services para las versiones ASP.NET en versiones anteriores a la 1.0.2, y entre 2.0.0 y 2.6.0, existe una vulnerabilidad en la forma en que se validan los tokens en algunos casos. Los tokens Saml2 generalmente se usan como token de portador: se supone que una persona que llama que presenta un token es el sujeto del token. También hay soporte en el protocolo Saml2 para emitir tokens vinculados a un sujeto a través de otros medios, p. titular de la clave donde debe demostrarse la posesión de una clave privada. La biblioteca Sustainsys.Saml2 trata incorrectamente todos los tokens entrantes como tokens de portador, aunque tengan otro método de confirmación de sujeto especificado. Esto podría ser utilizado por un atacante que podría obtener acceso a los tokens Saml2 con otro método de confirmación de sujeto que el portador. El atacante podría usar ese token para crear una sesión de inicio de sesión. Esta vulnerabilidad está parcheada en las versiones 1.0.2 y 2.7.0.

*Credits: N/A
CVSS Scores
Attack Vector
Network
Attack Complexity
Low
Privileges Required
Low
User Interaction
Required
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
None
Attack Vector
Network
Attack Complexity
High
Privileges Required
Low
User Interaction
Required
Scope
Changed
Confidentiality
High
Integrity
Low
Availability
None
Attack Vector
Network
Attack Complexity
Medium
Authentication
Single
Confidentiality
Partial
Integrity
Partial
Availability
None
* Common Vulnerability Scoring System
SSVC
  • Decision:-
Exploitation
-
Automatable
-
Tech. Impact
-
* Organization's Worst-case Scenario
Timeline
  • 2020-01-02 CVE Reserved
  • 2020-04-21 CVE Published
  • 2023-03-07 EPSS Updated
  • 2024-08-04 CVE Updated
  • ---------- Exploited in Wild
  • ---------- KEV Due Date
  • ---------- First Exploit
CWE
  • CWE-287: Improper Authentication
  • CWE-303: Incorrect Implementation of Authentication Algorithm
CAPEC
Affected Vendors, Products, and Versions
Vendor Product Version Other Status
Vendor Product Version Other Status <-- --> Vendor Product Version Other Status
Sustainsys
Search vendor "Sustainsys"
 Saml2
Search vendor "Sustainsys" for product "Saml2"
 < 1.0.2
Search vendor "Sustainsys" for product "Saml2" and version " < 1.0.2"
-
Affected
Sustainsys
Search vendor "Sustainsys"
 Saml2
Search vendor "Sustainsys" for product "Saml2"
 >= 2.0.0 < 2.7.0
Search vendor "Sustainsys" for product "Saml2" and version " >= 2.0.0 < 2.7.0"
-
Affected