Potential vulnerability in SCO TermVision Windows 95 client

From: JJ Gray (nexusat_private-WAY.CO.UK)
Date: Wed Mar 31 1999 - 07:50:13 PST

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    Hi folks,
    	I recently downloaded a trial version of the SCO TermVision terminal
    emulation package for
    SCO Openserver 5 and Windows 95 (
    http://www.sco.com/vision/products/termvision/ ).   This comes
    in two parts, the server based binaries and the Windows 95 client,
    TermVision 2.1.   In addition to the
    terminal emulation you get 'UNIX Neighborhood' which once supplied with a
    hostname, username &
    password gives an explorer/X-Windows style interface to the SCO server.
    In the default configuration
    the hostnames, usernames & passwords are saved in a file :
    C:\Windows\Profiles\%username%\Application
    Data\SCO\Vision\Auth\%username%.vca
    ( PC is Windows 95, NT4 server, user profiles ).   The data is encrypted
    but, not being a cryptanalysist,
    it took me a good 15 minutes to discover the encryption is nothing more
    than a fixed string XOR :(
    I informed SCO of this on 30th March and received a reply the next day :)
    --
    >From Matthew Schofield, Support <mattscat_private>
    
    JJ,
    
    Thanks for highlighting this issue in the Vision Comms.
    
    By your own definition it is insecure, in that the contents of the .vca
    files can be obtained
    with some effort. In terms of actually using someone's .vca file through
    the comms layer in
    order to access the UNIX resources through a Vision product, the files can
    only read by the
    comms layer if the user has successfully logged into Windows as that user.
    --
    Extracted from my reply -
    
    This is of no consequence.   The point is that I can extract the UNIX
    username & password from another user that has used the same PC.
    If that user happens to use root access then I have the root password -
    thus a non privileged user with windows access can gain root privs on
    the UNIX box, whether through UNIX Neighborhood, terminal emulation,
     a terminal itself, telnet etc.   If I were a windows user with no user
    account on the UNIX box......... :)
    --
    When adding a host, the security options can be set to 'Prompt' where the
    password
    is not saved.   Yes this is only a potential security hole - another on the
    'Configuration'
    issue, but it is not obvious that this vulnerability exists.   The default
    is insecure and there
    is no 'obvious' information in the documentation that it is so - hence my
    post.
    Matthew finished by saying
    --
    As you have already identified, you should change the password mechanism
    for your host to
    prompt. In a future release we intend to either change the operation of the
    password mechanism
    or add an appropriate warning.
    --
    Can't really say fairer than that I suppose...
    
    Regards,
    	JJ Gray
    
    
    Sed quis custodiet ipsos custodes ?
    



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