CVE‐2023‐33201

Issue affecting: BC 1.73 and earlier.

Fixed versions: BC 1.74

Platform affected: Java 4 and later.

Bouncy Castle provides the X509LDAPCertStoreSpi.java class which can be used in conjunction with the CertPath API for validating certificate paths. Pre-1.73 the implementation did not check the X.500 name of any certificate, subject, or issuer being passed in for LDAP wild cards, meaning the presence of a wild card may lead to Information Disclosure.

A potential attack would be to generate a self-signed certificate with a subject name that contains special characters, e.g: CN=Subject*)(objectclass=. This will be included into the filter and provides the attacker ability to specify additional attributes in the search query. This can be exploited as a blind LDAP injection: an attacker can enumerate valid attribute values using the boolean blind injection technique. The exploitation depends on the structure of the target LDAP directory, as well as what kind of errors are exposed to the user.

Changes to the X509LDAPCertStoreSpi.java class add the additional checking of any X.500 name used to correctly escape wild card characters.

We gratefully acknowledge the efforts of GitHub Security Lab team member @artsploit (Michael Stepankin) in identifying this issue.