Alan Cox intimated on bugtraq that he has found some bugs in resolv+.
The bugs have been about for years and concern the passing of
enviromental variables to resolv+ code (which is normally called by
ping, rlogin, rsh, ssh etc). Since it looks like the cat is about to
leap from the bag, I think I had better explain. Resolv+ is a library,
often incorporated with libc, but sometimes stand alone (e.g -lresolv).
It contains gethostbyname()/gethostbyaddr() as well as other dns
functions.  As an example of wonders of resolv+:

$ export RESOLV_HOST_CONF=/etc/shadow
$ rlogin thepopeneverlikedbadgersanywaymate

Linux is prone to this. Solaris/Sunos does not appear to be. FreeBSD is
not. But thats ok, they make up for it with NLS/Locale, which is a far, far
bigger problem.