AUSCERT External Security Bulletin Redistribution

                 ESB-97.053 -- SUN Security Bulletin #00139
                              30 April 1997


Sun Microsystems has released the following security bulletin giving patch
information which addresses a vulnerability in the pluggable authentication
module (PAM). This vulnerability may allow local users to gain root access.

This bulletin addresses the vulnerability previously described in the
AUSCERT Advisory AA-97.09 - Solaris 2.x passwd buffer Overrun Vulnerability.

The following security bulletin is provided as a service to AUSCERT's
members.  As AUSCERT did not write this document, AUSCERT has had no
control over its content.  As such, the decision to use any or all of this
information is the responsibility of each user or organisation, and should
be done so in accordance with site policies and procedures.

Contact information for Sun Microsystems is included in the Security
Bulletin below.  If you have any questions or need further information,
please contact them directly.

If you believe that your system has been compromised, contact AUSCERT or
your representative in FIRST (Forum of Incident Response and Security

Internet Email: auscert@auscert.org.au
Facsimile:      (07) 3365 4477
Telephone:      (07) 3365 4417 (International: +61 7 3365 4417)
	AUSCERT personnel answer during Queensland business hours
	which are GMT+10:00 (AEST).
	On call after hours for emergencies.

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Sun announces the release of patches for Solaris 2.5.1 (SunOS 5.5.1) and 
Solaris 2.5 (SunOS 5.5) that relate to vulnerabilities in the pluggable 
authentication module (PAM), which can result in root access if exploited. 
The nispasswd, yppasswd, and passwd programs use PAM in these OS releases.

Sun estimates that the release of patches for Solaris 2.4 (SunOS 5.4) and 
Solaris 2.3 (SunOS 5.3) that relate to the same vulnerability will be 
available within 5 weeks and 6 weeks respectively of the date of this bulletin.
In Solaris 2.4 and 2.3, the passwd programs use unix_scheme instead of PAM.

Sun strongly recommends that you install these patches immediately on
every affected system. Exploit information is publicly available.

I.   Who is Affected, and What to Do

II.  Understanding the Vulnerabilities

III. List of Patches

IV.  Checksum Table


A.   How to obtain Sun security patches

B.   How to report or inquire about Sun security problems

C.   How to obtain Sun security bulletins or short status updates

Sun acknowledges with thanks the CERT Coordination Center (Carnegie
Mellon University) and AUSCERT for their assistance in the preparation of 
this bulletin.

Sun, CERT/CC, and AUSCERT are members of FIRST, the Forum of Incident
Response and Security Teams. For more information about FIRST, visit
the FIRST web site at "http://www.first.org/".

Cross-Ref:	AUSCERT AA-97.09


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.


I.   Who is Affected, and What to Do
     SunOS versions 5.5.1, 5.5.1_x86, 5.5, 5.5_x86, 5.4, 5.4_x86, and 5.3
     are vulnerable.
     SunOS versions 4.1.4 and 4.1.3_U1 are not vulnerable.
     Install the patches listed in III. for SunOS versions 5.5.1, 5.5.1_x86, 
     5.5, and 5.5_x86.
     Sun estimates that patches for SunOS versions 5.4 and 5.4_x86 will 
     be released within 5 weeks from the date of this bulletin. Sun also 
     estimates that patches for SunOS version 5.3 will be released within 6 
     weeks from the date of this bulletin. In the meantime, Sun recommends, as 
     a workaround, the installation of a passwd wrapper that was developed by 
     AUSCERT (see AUSCERT Advisory AA-97.09). AUSCERT maintains an anonymous 
     FTP service at ftp://ftp.auscert.org.au/pub/ and a World Wide Web service 
     at http://www.auscert.org.au/.
     The same vulnerability has been fixed in the upcoming release of Solaris.

II.  Understanding the Vulnerability

Due to insufficient bounds checking on arguments in PAM (5.5.1 and 5.5) and 
unix_scheme (5.4 and 5.3), it is possible to overwrite the internal stack space 
of the passwd program. If exploited, this vulnerability can be used to gain 
root access on attacked systems. 

Under SunOS 5.5.1 and 5.5, yppasswd and nispasswd are hard links to the passwd 
program and therefore are also vulnerable. Under SunOS 5.4 and 5.3, passwd, 
yppasswd, and nispasswd are separate programs but they dynamically link 
unix_scheme and are affected.

III. List of Patches

The vulnerabilities relating to passwd in PAM and unix_scheme are fixed by 
the following patches:

	OS version		Patch ID
	----------		--------
	SunOS 5.5.1		104433-03
	SunOS 5.5.1_x86		104434-02
     	SunOS 5.5		103178-03
	SunOS 5.5_x86		103179-03
	SunOS 5.4		101945-49	(to be released in 5 weeks)
	SunOS 5.4_x86		101946-43	(to be released in 5 weeks)
	SunOS 5.3		101318-87	(to be released in 6 weeks)

IV.  Checksum Table

In the table below, we show 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 compressed tar files.

File              BSD          SVR4          MD5                             
Name              Checksum     Checksum      Digital Signature               
- ---------------   ---------    ---------     --------------------------------
104433-03.tar.Z   38148 225    11004 449     80C625D86DBFA06C107956EB4BD8126A
104434-02.tar.Z   22283 142    51656 284     4079E48BB8BA929F99EFE4D38877B023
103178-03.tar.Z   11476 212    51066 423     74547F3FDF850FAAF6B02176CF146AA4
103179-03.tar.Z   55629 192    1250 384      CA11D05845116F62FCC8DDCC6EDBCB2B


A.   How to obtain Sun security patches

    1. If you have a support contract

    Customers with Sun support contracts can obtain any patches listed
    in this bulletin (and any other patches--and a list of patches) from:

       - SunSolve Online
       - Local Sun answer centers, worldwide
       - SunSITEs worldwide

    The patches are available via World Wide Web at http://sunsolve.sun.com. 

    You should also contact your answer center if you have a support
    contract and:

       - You need assistance in installing a patch 
       - You need additional patches
       - You want an existing patch ported to another platform
       - You believe you have encountered a bug in a Sun patch
       - You want to know if a patch exists, or when one will be ready

    2. If you do not have a support contract

    Customers without support contracts may now obtain security patches,
    "recommended" patches, and patch lists via SunSolve Online.
    Sun does not furnish patches to any external distribution sites
    other than the ones mentioned here. The ftp.uu.net and ftp.eu.net
    sites are no longer supported.

    3. About the checksums

    So that you can quickly verify the integrity of the patch files
    themselves, we supply in each bulletin checksums for the tar archives.

    Occasionally, you may find that the listed checksums do not match
    the patches on the SunSolve or SunSite database. This does not
    necessarily mean that the patch has been tampered with. More likely,
    a non-substantive change (such as a revision to the README file)
    has altered the checksum of the tar file. The SunSolve patch database
    is refreshed nightly, and will sometimes contain versions of a patch
    newer than the one on which the checksums were based.

    In the future we may provide checksum information for the
    individual components of a patch as well as the compressed archive
    file. This would allow customers to determine, if need be, which
    file(s) have been changed since we issued the bulletin containing
    the checksums.

    In the meantime, if you would like assistance in verifying the
    integrity of a patch file please contact this office or your local
    answer center.

B.   How to report or inquire about Sun security problems

If you discover a security problem with Sun software or wish to
inquire about a possible problem, contact one or more of the
   - Your local Sun answer centers
   - Your representative computer security response team, such as CERT 
   - This office. Address postal mail to:

         Sun Security Coordinator
         MS MPK17-103
         2550 Garcia Avenue
	 Mountain View, CA 94043-1100
         Email: security-alert@sun.com
We strongly recommend that you report problems to your local Answer
Center. In some cases they will accept a report of a security bug
even if you do not have a support contract. An additional notification
to the security-alert alias is suggested but should not be used as your
primary vehicle for reporting a bug.

C.   How to obtain Sun security bulletins or short status updates

    1. Subscription information

    Sun Security Bulletins are available free of charge as part of
    our Customer Warning System. It is not necessary to have a Sun
    support contract in order to receive them.

    To receive information or to subscribe or unsubscribe from our
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        Subject         Information Returned/Action Taken
        -------         ---------------------------------

        HELP            An explanation of how to get information

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        QUERY [topic]   The mail containing the question is relayed to
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        REPORT [topic]  The mail containing the text is treated as a
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    2. Obtaining old bulletins

    Sun Security Bulletins are available via the security-alert alias
    and on SunSolve. Please try these sources first before contacting
    this office for old bulletins.


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