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SCO Security Bulletin 99.26c
17 July 2000
Multiple Vulnerabilities Found In SCO OpenServer (xclient perms)
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I.   Description

This is an update to SB 99.26b (24th Feb 2000)  describing 
a replacement SSE for sse050 (sse050c)

SSE050c  corrects an error with sse050b where the permissions on the 
replacement file in /usr/bin/X11 were incorrect
This and the original SSE address the following.

Several security holes have been found in SCO OpenServer:

  1. Buffer overflows in:

    /usr/mmdf/chans/smtpsrvr
    /etc/killall
    /etc/popper
    /usr/bin/mscreen
    /usr/bin/rlogin
    /bin/su 
    /usr/lib/sysadm/termsh
    /usr/lib/libX11.so.5.0
    /usr/lib/libXt.so.5.0
    /usr/lib/libXmu.so.5.0
    /usr/lib/libXaw.so.5.0
    /usr/lib/libX11.a
    /usr/lib/libXt.a
    /usr/lib/libXmu.a
    /usr/lib/libXaw.a
    /usr/bin/X11/xterm
    /usr/bin/X11/xload
    /usr/bin/X11/scoterm
    /usr/bin/X11/scolock
    /usr/bin/X11/scosession
    /usr/bin/X11/scologin
    /usr/lpd/remote/rlpstat	
    /usr/lpd/remote/cancel
    /usr/lpd/remote/lpmove


  2. Algorithmic vulnerabilities in:

    /etc/sysadm.d/bin/userOsa:
      Can improperly write to privileged files

    /usr/bin/X11/Xsco:
      Can improperly read privileged files (also buffer overflows)

    /bin/hello:
      Can improperly acess privileged devices 
      Allows transmission of dangerous characters

    /bin/write:
      Allows transmission of dangerous characters

    /bin/login:
      Corrupt /etc/dialups causes login failure
      Insufficient error checking


II.  Impact

Unprivileged users can gain administrative privileges on unpatched
servers.


III. Releases

SCO products that require patching include OpenServer version 5.0.5.


IV.  Solution

SCO is providing an interim patch to address this issue in the form of a
System Security Enhancement (SSE) package.

SSE050c contains replacement binaries for each system type, and is
available for Internet download via anonymous ftp

You can download the SSE package as follows:

Anonymous ftp (World Wide Web URL):

    ftp://ftp.sco.COM/SSE/sse050c.ltr    (cover letter, ASCII text)
    ftp://ftp.sco.COM/SSE/sse050c.tar.Z  (new binaries, compressed tar file)

Checksums (sum -r):

    01553     7 sse050c.ltr
    18053  5356 sse050c.tar.Z


V.   Updates

This bulletin is available for anonymous ftp download from 
ftp://ftp.sco.COM/SSE/security_bulletins/SB-99.26c and updates
ftp://ftp.sco.COM/SSE/security_bulletins/SB-99.26b 
This will be updated as new information becomes available.

The latest information on security vulnerabilities and fixes from
SCO is available on the world-wide web at http://www.sco.com/security/

VI.  Further Information:

If you have further questions, contact your support provider.  If you
need to contact SCO, please send electronic mail to support@sco.COM, or
contact SCO as follows. 

    USA/Canada: 6am-5pm Pacific Time (PST/PDT)
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    1-800-347-4381  (voice)
    1-408-427-5443  (fax)

    Pacific Rim, Asia, and Latin American customers: 6am-5pm Pacific
    ------------------------------------------------ Time (PST/PDT)
    1-408-425-4726  (voice)
    1-408-427-5443  (fax)

    Europe, Middle East, Africa: 9am-5:30pm UK Time (GMT/BST)
    ----------------------------
    +44 (0)1923 816344 (voice)
    +44 (0)1923 817781 (fax)