Updated krb5 packages which fix two buffer overflow vulnerabilities in the included Kerberos-aware telnet client are now available. This update has been rated as having important security impact by the Red Hat Security Response Team.
Kerberos is a networked authentication system which uses a trusted third party (a KDC) to authenticate clients and servers to each other. The krb5-workstation package includes a Kerberos-aware telnet client. Two buffer overflow flaws were discovered in the way the telnet client handles messages from a server. An attacker may be able to execute arbitrary code on a victim's machine if the victim can be tricked into connecting to a malicious telnet server. The Common Vulnerabilities and Exposures project (cve.mitre.org) has assigned the names CAN-2005-0468 and CAN-2005-0469 to these issues. Users of krb5 should update to these erratum packages which contain a backported patch to correct this issue. Red Hat would like to thank iDEFENSE for their responsible disclosure of this issue.