COMMAND
webpsvr
SYSTEMS AFFECTED
TalentSoft Web+
PROBLEM
Following is based on Security Advisory by Sword & Shield
Enterprise Security. The TalentSoft Web+ server allows users to
read arbitrary data files on the Web server running the webpsvr
daemon. By entering a crafted URL any user with a browser can
retrieve files that the webpsvr daemon itself has access to.
The webpsvr daemon is the driving process for the TalentSoft, Inc.
Web based e-commerce software. The Web+ server runs under a
standard web server, such as Apache. Users run a CGI script
called webplus (webplus.exe on Windows), which communicates with
webpsvr to serve up the web pages for the electronic store that
is implemented by Web+. In a typical installation of Web+, the
following URL will bring up the Web+ storefront:
http://yourhost.com/cgi-bin/webplus?script=/script_dir/store.wml
The webpsvr daemon is handed the script variable, and serves up
the generated page. Through use of the string ".." a URL can be
crafted that will allow any browser to see arbitrary files on the
web server. For example, the URL:
http://yourhost.com/cgi-bin/webplus?script=/../../../../etc/passwd
will display the contents of the file /etc/passwd if read access
is available to the webpsvr daemon. If webpsvr is running under
the root userid, this essentially means that *any* file on the
system can be viewed by any user (local or remote). It should be
noted that the default installation of Web+ will have webpsvr run
as user "nobody", and not root, so the scope of the vulnerability
is reduced to group owned and world readable files.
The impact of this bug can be quite severe. Since this is an
e-commerce package it will likely be used on web sites that are
accessible to any IP address world wide, and this bug will allow
users to gather vital information about the system running the
Web+ software that could be used in exploits against the system.
This bug is known to exist in Web+ 4.X as of March 1999, and is
believed, though unverified, to exist in all previous versions.
The vulnerability was tested and confirmed on a RedHat 6.1 Linux
system. The latest webpsvr binary that is known to contain this
bug is Build 506. Build information can be obtained by entering
the URL:
http://yourhost.com/cgi-bin/webplus?about
The bug discovery, test, demonstration, vendor coordination, and
advisory generation are the results of SSES, Inc. security
engineers Dennis Edmonds, Karl Allen, and Matt Smith.
SOLUTION
This problem has been corrected in builds of webplus after 512.
For those who need the upgraded binary, you can either contact
support@talentsoft.com for a link to the patch, or obtain the
patch from the web site (www.talentsoft.com).