CVE-2015-2694

Los módulos kdcpreauth en MIT Kerberos 5 (también conocido como krb5) 1.12.x y 1.13.x anterior a 1.13.2 no rastrea correctamente si la solicitud de un cliente ha sido validada, lo que permite a atacantes remotos evadir un requisito de preautenticación mediante la provisión de (1) cero bytes de datos o (2) un nombre de ámbito (realm) arbitrario, relacionado con plugins/preauth/otp/main.c y plugins/preauth/pkinit/pkinit_srv.c.

A flaw was found in the OTP kdcpreauth module of MIT Kerberos. A remote attacker could use this flaw to bypass the requires_preauth flag on a client principal and obtain a ciphertext encrypted in the principal's long-term key. This ciphertext could be used to conduct an off-line dictionary attack against the user's password.

Kerberos is a network authentication system, which can improve the security of your network by eliminating the insecure practice of sending passwords over the network in unencrypted form. It allows clients and servers to authenticate to each other with the help of a trusted third party, the Kerberos key distribution center. It was found that the krb5_read_message() function of MIT Kerberos did not correctly sanitize input, and could create invalid krb5_data objects. A remote, unauthenticated attacker could use this flaw to crash a Kerberos child process via a specially crafted request.