26th Sep 2002 [SBWID-5251]
COMMAND
multiple CGIscript.net scripts remote code execution
SYSTEMS AFFECTED
csGuestbook
csLiveSupport
csNewsPro
csChatRBox
PROBLEM
Steve Gustin found following vulnerabilities on some CGIscript.net
scripts :
CGIScript.net distributes a number of free and commercial perl cgi
scripts developed by Mike Barone and Andy Angrick. Last month a Remote
Code Execution vulnerability was found in their csSearch product,
further research and information provided by the Vendor has revealed
that four (4) additional scripts have the same vulnerability.
These scripts are:
csGuestBook - guestbook program
csLiveSupport - web based support/chat program
csNewsPro - website news updater/editor
csChatRBox - web based chat script
These scripts stores their configuration data as perl code in a file
called "setup.cgi" which is eval()uated by the script to load it back
into memory at runtime. Due to an Access Validation Error, any user can
cause configuration data to be written to "setup.cgi" and therefore
execute arbitrary perl code on the server.
EXPLOIT
=======
Configuration data is (typically) saved with the following URL.
scriptname.cgi?command=savesetup&setup=PERL_CODE_HERE
Note that any perl code would need to be URL encoded. A malicious user
could essentially execute any arbitrary perl code or shell commands.
Only csChatRBox was tested for this vulnerability, however, Vendor
stated the other scripts were also affected.
SysAdmins wanting to scan for affected scripts should check for the
following filenames: "csGuestbook.cgi", "csLiveSupport.cgi",
"csNews.cgi", "csChatRBox.cgi".
IMPACT
======
Because of the high number of users who are using CGIscript.net scripts
(over 17,000 csSearch users alone according to the website) and the
fact that search engines can easily be used to identify sites with the
unique "csScriptName.cgi" script names, the risk posed by these flaws
is very high indeed.
Additionally, because the Vendor does not post version numbers or
changlogs (that we could find) on their website or with their software,
and because the patched version of csChatRBox has the same version
number of the vulnerable version (1.0), it may make it more difficult
for users to determine whether or not their script is vulnerable or
not.
SOLUTION
Vendor has released updated versions of all the affected scripts to
patch the flaws.