AUSCERT External Security Bulletin Redistribution

                 ESB-97.104 -- Sun Security Bulletin #00150
                           Vulnerability in xlock

			       14 August 1997


Sun Microsystems, Inc has released the following advisory concerning a
vulnerability in xlock.  This vulnerability may allow local users to gain
root privileges.

The following security bulletin is provided as a service to AUSCERT's
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Bulletin below.  If you have any questions or need further information,
please contact them directly.

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 		   Sun Microsystems, Inc. Security Bulletin
Bulletin Number:	#00150
Date: 			August 12, 1997
Cross-Ref:		CERT CA-97.13
Title:			Vulnerability in xlock
Permission is granted for the redistribution of this Bulletin, so long as 
the Bulletin is not edited and is attributed to Sun Microsystems. Portions 
may also be excerpted for re-use in other security advisories so long as 
proper attribution is included.

Any other use of this information without the express written consent of 
Sun Microsystems is prohibited. Sun Microsystems expressly disclaims all 
liability for any misuse of this information by any third party.

1.  Bulletins Topics

    Sun announces the release of patches for Solaris 2.5.1, 2.5, 2.4, 2.3,   
    (SunOS 5.5.1, 5.5, 5.4, 5.3), SunOS 4.1.4, and 4.1.3_U1, which relate 
    to a vulnerability in the xlock program.

    Sun strongly recommends that you install the patches listed in section 4 
    immediately on systems running SunOS 5.5.1, 5.5, 5.4, 5.3, 4.1.4, and
    4.1.3_U1. Exploit information is publicly available.

2.  Who is Affected
    Vulnerable:  SunOS versions 5.5.1, 5.5.1_x86, 5.5, 5.5_x86,
                                5.4, 5.4_x86, 5.3, 4.1.4, and 4.1.3_U1
    The vulnerability is fixed in the upcoming release of Solaris.

3.  Understanding the Vulnerability

    The xlock program locks the local X display until the user supplies a 
    password. Due to insufficient bounds checking on arguments supplied to 
    xlock it is possible to overwrite the stack space of the xlock program. 
    As xlock is setuid root, this vulnerability may be exploited by users on 
    a system to gain root access.

4.  List of Patches

    The vulnerability in xlock is fixed by the following patches:

    OS version          Patch ID
    __________		________
    SunOS 5.5.1		103566-20		
    SunOS 5.5.1_x86	105109-01	
    SunOS 5.5		103210-20	
    SunOS 5.5_x86	105108-01	
    SunOS 5.4		102057-38	
    SunOS 5.4_x86	105110-01	
    SunOS 5.3		101362-50
    SunOS 4.1.4		100478-02
    SunOS 4.1.3_U1	100478-02	

5.  Checksum Table

    The checksum table below shows the BSD checksums (SunOS 4.1.x: /bin/sum; 
    SunOS 5.x: /usr/ucb/sum), SVR4 checksums (SunOS 5.x: /usr/bin/sum), and 
    the MD5 digital signatures for the above-mentioned patches that are 
    available from:
    These checksums may not apply if you obtain patches from your answer

File Name	  BSD	      SVR4	   MD5
_______________   _________   __________   _______________________________
103566-20.tar.Z   01319 3189  4044 6378    D7534B10A32CC600972973B39850A622
105109-01.tar.Z   44172 144   14499 287    16CEC591C71EE814E8475EC62EAF2903
103210-20.tar.Z   45065 3270  36740 6540   E413A4D5CD4A43F3ACDDDF3E78628099
105108-01.tar.Z   55743 143   43259 286    8EA202FF2C7D2FEA47424FBA53F11FA2
102057-38.tar.Z   09646 1909  60808 3817   D3C1FEB1C242DDD68BAA4F56DB70CD3F
105110-01.tar.Z   05813 130   30121 260    2CE9A43C4F38D787AFAAE92E57287553
101362-50.tar.Z   12142 6482  58259 12964  887B3277462D9051D4630C7A753855C3
100478-02.tar.Z   09802 60    47925 120    1981F145B09AAAC7B73193FF82DDF8D5

A.  Patches listed in this bulletin are available to all Sun customers via 
    World Wide Web at:
    Customers with Sun support contracts can also obtain patches from local 
    Sun answer centers and SunSITEs worldwide.

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