mailing list archives
Re: fingerd problems
From: brian () saturn net (Brian Mitchell)
Date: Fri, 17 May 1996 02:41:47 -0400
On Thu, 16 May 1996, Elliot Lee wrote:
[ list of ways to list all the users on a system using fingerd ]
Another vulnerability of many finger daemons is their ability to support
'chain' fingers. If they are passed a "username" in the form of
'user () ahost net' the finger daemon will repeat the finger, effectively
hiding the tracks of anyone trying to scope out your system security.
For a demonstration, 'telnet prep.ai.mit.edu 79' and type
'[yourname] () [yourhost]'. If you have TCP wrappers installed, you will
notice that the finger connection comes from prep.ai.mit.edu, not [yourhost].
Some www servers also include the 'finger' cgi program, which can be used
in much the same way, ie:
lynx http://www.cgis.net/cgi-bin/finger\?user () host
Brian Mitchell brian () saturn net
"I never give them hell. I just tell the truth and they think it's hell"
- H. Truman