CVE-2023-41890: Sustainsys.Saml2 Insufficient Identity Provider Issuer Validation
Impact When a response is processed, the issuer of the Identity Provider is not sufficiently validated. This could allow a malicious identity provider to craft a Saml2 response that is processed as if issued by another identity provider. It is also possible for a malicious end user to cause stored state intended for one identity provider to be used when processing the response from another provider.
An application is impacted if they rely on any of these features in their authentication/authorization logic: the issuer of the generated identity and claims items in the stored request state (AuthenticationProperties)
Patches Patched in version 2.9.2 and 1.0.3. All previous versions are vulnerable.
Workarounds The AcsCommandResultCreated notification can be used to add the validation required if an upgrade to patched packages is not possible.
References The patch is linked to https://github.com/Sustainsys/Saml2/issues/712 and https://github.com/Sustainsys/Saml2/issues/713
Other sources
Sustainsys.Saml2 library adds SAML2P support to ASP.NET web sites, allowing the web site to act as a SAML2 Service Provider. Prior to versions 1.0.3 and 2.9.2, when a response is processed, the issuer of the Identity Provider is not sufficiently validated. This could allow a malicious identity provider to craft a Saml2 response that is processed as if issued by another identity provider. It is also possible for a malicious end user to cause stored state intended for one identity provider to be used when processing the response from another provider. An application is impacted if they rely on any of these features in their authentication/authorization logic: the issuer of the generated identity and claims; or items in the stored request state (AuthenticationProperties). This issue is patched in versions 2.9.2 and 1.0.3. The AcsCommandResultCreated notification can be used to add the validation required if an upgrade to patched packages is not possible.
— NVD
Affected Software
Remediation
Patch Available
Patch Available
Event History
Frequently Asked Questions
What is CVE-2023-41890?
CVE-2023-41890 is a vulnerability in the Sustainsys.Saml2 library that allows a malicious identity provider to craft a Saml2 response that is processed as if issued by another identity provider.
How does CVE-2023-41890 impact ASP.NET web sites?
CVE-2023-41890 allows a malicious identity provider or end user to exploit the vulnerability, potentially leading to unauthorized access or impersonation.
What is the severity of CVE-2023-41890?
CVE-2023-41890 has a severity rating of 7.5 (high).
How can I fix CVE-2023-41890 in my ASP.NET web site?
To fix CVE-2023-41890, update the Sustainsys.Saml2 library to version 2.9.2 or apply the appropriate remedy provided by Sustainsys.
Where can I find more information about CVE-2023-41890?
You can find more information about CVE-2023-41890 on the official GitHub page of Sustainsys.Saml2 library.