COMMAND
Scour
SYSTEMS AFFECTED
Scour client
PROBLEM
'Jmp' found following. Scour (www.scour.net) is a file sharing
client much like Gnutella and Napster. Scour provides a search
engine that is devoted to searching the Scour Community or the
web for multimedia files.
Use is simple: setup a folder where you download files to and
specify folders to share with the rest of the Scour community.
The client is coded so that it only returns back multimedia files
(mp2,mp3,,vivo,ra,mpeg,etc.) when one browses another user's
shared files. Also no wildcards are supported and only file
formats hard coded into the client can be
searched/viewed/downloaded.
A person already has read access to the shared folders on
someone's machine using scour. The file format restrictions can
easily be circumvented, since as stated above, they are all hard
coded into the client. At present Scour has only released a Win32
client (as well as a user provided perl client), and it is trivial
to use a hex editor and simply replace eg. MP2 with FOO or MOO
(use your imagination here) or any other file type. Once this is
done, the client allows for the user to search for those file
types (apparently no CRC checking is done to detect if the binary
has been modified or not). This would normally not be a problem,
however we have seen quite a few users who share their WINDOWS/
or PROGRAM FILES/ (i.e. sensitive) directories thinking that
another user will not be able to download anything else. Thus
there are quite a few people out there who are lulled into a
false sense of security. A person also need not bother with
having to hex edit the binary since Scour has released it's
protocol
http://www.scour.net/Software/Scour_Exchange/stp-1.0pre6.html
thus making it quite easy for anyone who knows how to code and
work with sockets, to create their own client. He/she could then
quite easily implement and allow for any and all files to be
searched/downloaded.
SOLUTION
Scour should implement filters on their server itself so that
only the file types they specified could be searched and
downloaded. However it is uknown when and if that's going to be
happening. So until then it is strongly suggested to Scour users
to get a LOT more picky about which folders they wish to share
since a person can see and get anything and everything in those
folders.