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RHSA-2014:1245: krb5 security and bug fix update (Moderate)


Kerberos is an authentication system which allows clients and services to authenticate to each other with the help of a trusted third party a Kerberos Key Distribution Center (KDC). It was found that if a KDC served multiple realms certain requests could cause the setup_server_realm() function to dereference a NULL pointer. A remote unauthenticated attacker could use this flaw to crash the KDC using a specially crafted request. (CVE-2013-1418 CVE-2013-6800) A NULL pointer dereference flaw was found in the MIT Kerberos SPNEGO acceptor for continuation tokens. A remote unauthenticated attacker could use this flaw to crash a GSSAPI-enabled server application. (CVE-2014-4344) A buffer over-read flaw was found in the way MIT Kerberos handled certain requests. A man-in-the-middle attacker with a valid Kerberos ticket who is able to inject packets into a client or server application's GSSAPI session could use this flaw to crash the application. (CVE-2014-4341) This update also fixes the following bugs: * Prior to this update the libkrb5 library occasionally attempted to free already freed memory when encrypting credentials. As a consequence the calling process terminated unexpectedly with a segmentation fault. With this update libkrb5 frees memory correctly which allows the credentials to be encrypted appropriately and thus prevents the mentioned crash. (BZ#1004632) * Previously when the krb5 client library was waiting for a response from a server the timeout variable in certain cases became a negative number. Consequently the client could enter a loop while checking for responses. With this update the client logic has been modified and the described error no longer occurs. (BZ#1089732) All krb5 users are advised to upgrade to these updated packages which contain backported patches to correct these issues. After installing the updated packages the krb5kdc daemon will be restarted automatically.

  • CentOS Linux 5
  • Red Hat Enterprise Linux 5
  • RHSA-2014:1245-00
  • CVE-2013-1418
  • CVE-2013-6800
  • CVE-2014-4341
  • CVE-2014-4344
  • CESA-2014:1245
  • krb5