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Improper Certificate Validation

CVE-2019-3875

Severity Medium
Score 4.8/10

Summary

A vulnerability was found in keycloak before 6.0.0. The X.509 authenticator supports the verification of client certificates through the CRL, where the CRL list can be obtained from the URL provided in the certificate itself (CDP) or through the separately configured path. The CRL are often available over the network through unsecured protocols ('http' or 'ldap') and hence the caller should verify the signature and possibly the certification path. Keycloak currently doesn't validate signatures on CRL, which can result in a possibility of various attacks like man-in-the-middle.

  • HIGH
  • NETWORK
  • LOW
  • UNCHANGED
  • NONE
  • NONE
  • LOW
  • NONE

CWE-295 - Improper Certificate Validation

The authenticity component of a web system stems from the ability to validate “Digital certificates”, which (i) establish trust between two or more entities sharing data over a network; (ii) ensure data at rest and transit is secure from unauthorized access; and (iii) check the identity of the actors that interact with the system. An application with absent or ineffective certificate validation mechanisms allows malicious users, impersonating trusted hosts, to manipulate the communication path between the client and the host, resulting in unauthorized access to data and to the application’s internal environment, and potentially enabling man-in-the-middle attacks.

Advisory Timeline

  • Published