Heimdal: Buffer overflow vulnerabilities

Background

Heimdal is a free implementation of Kerberos 5 that includes a telnet client program.

Description

Buffer overflow vulnerabilities in the slc_add_reply() and env_opt_add() functions have been discovered by Gael Delalleau in the telnet client in Heimdal.

Impact

Successful exploitation would require a vulnerable user to connect to an attacker-controlled host using the telnet client, potentially executing arbitrary code with the permissions of the user running the application.

Workaround

There is no known workaround at this time.

Resolution

All Heimdal users should upgrade to the latest version:

 # emerge --sync
 # emerge --ask --oneshot --verbose ">=app-crypt/heimdal-0.6.4"