COMMAND
fingerd
SYSTEMS AFFECTED
SunOS
PROBLEM
Jens Hektor found following. He recently found on a compromised
host somewhere a script containing the following very interesting
line was found:
finger "0 1 2 3 4 5 6 7 8 9"@host
If "host" is a Solaris host with finger service enabled in
/etc/inetd.conf, one will get a complete (?) list of accounts on
this system.
Actually, the good old finger forwarding 'feature' ist still
possible with Suns and it's well documented in the manual page.
Still, it works even with Solaris 8.
SOLUTION
Disable finger service in /etc/inetd.conf. SUN has assigned a
bugid (4298915:'in.fingerd can store a NULL after end of an array
on the stack') for the described problem and stated that they are
working on a patch for all affected versions.
Well, not to flaunt the obvious, but the best solution to this is
# grep finger /etc/inetd.conf
#finger stream tcp nowait nobody /usr/sbin/in.fingerd in.fingerd