Hash: SHA1

             AUSCERT External Security Bulletin Redistribution

                          ESB-2006.0694 -- [AIX]
Vulnerability in /etc/slip.login may allow for arbitrary command execution
                             26 September 2006


        AusCERT Security Bulletin Summary

Product:              /etc/slip.login
Publisher:            IBM
Operating System:     AIX 5.3
                      AIX 5.2
Impact:               Root Compromise
Access:               Existing Account

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Hash: SHA1


First Issued: Tue Sep 26 10:00:16 CDT 2006
                           VULNERABILITY SUMMARY

VULNERABILITY:      A vulnerability in /etc/slip.login will allow a
                    local user to execute arbitrary code with root

PLATFORMS:          AIX 5.2 and 5.3.

SOLUTION:           Apply the APAR, interim fix or workaround as
                    described below.

THREAT:             A local user may execute arbitrary code with root

CERT VU Number:     n/a
CVE Number:         n/a
                           DETAILED INFORMATION

I.  Description

A security vulnerability in /etc/slip.login may allow a local user to
execute arbitrary code with root privileges. /etc/slip.login is an
initialization script used when converting a standard-input terminal line
into a Serial Line Internet Protocol (SLIP) link to a remote host.

/etc/slip.login ships as part of the bos.net.tcp.client fileset.

To determine if a fileset is installed, execute the following command:

# lslpp -L bos.net.tcp.client

The fileset will be listed along with its version information, state, type
and a description.

The following table shows the vulnerable versions of bos.net.tcp.client. 

AIX Release          Lower         Upper
                     Level         Level
AIX 5.2    
AIX 5.3    

II. Impact

A local user may execute arbitrary commands with root privileges.

III.  Solutions

A. Official Fix

IBM provides the following fixes:

      APAR number for AIX 5.2.0:  IY88566 (available)
      APAR number for AIX 5.3.0:  IY88615 (available approx. 10/04/06)

NOTE: Affected customers are urged to upgrade to the latest applicable
Technology Level.

B. Interim Fix

Interim fixes are available. The ifixes can be downloaded via ftp from:


This is a compressed tarball containing this advisory, interim fix packages
and cleartext PGP signatures for each package.

Verify you have retrieved the fixes intact:
The interim fixes below are named by using the APAR corresponding to the
release that the fix applies to. The APAR is followed by an underscore and
the Technology Level for the particular AIX release that a fix applies to.

The checksums below were generated using the "sum" and "md5sum" commands
and are as follows:

The interim fixes below include prerequisite checking. This will enforce
the correct mapping between the fixes and AIX Technology Levels. 

Filename                   sum           md5
IY88566_07.091906.epkg.Z   35585     4   c1a39db8ecfb9fb88b92a5d952558310
IY88566_08.091906.epkg.Z   64356     4   459ee16f1691c8463953fec7719eaaa8
IY88566_09.091906.epkg.Z   05225     4   a3362556c84c49f3ad822f3ab9ba2b09
IY88615_03.091906.epkg.Z   02913     4   b07f0d45d63eb51552ef7fc771d92fa8
IY88615_04.091906.epkg.Z   30678     4   d774af099011d7eee81e28acf976671f
IY88615_05.091906.epkg.Z   15527     4   dda945164ca8ff89a45670339a95aeba

These sums should match exactly. The PGP signatures in the compressed
tarball and on this advisory can also be used to verify the integrity of
the various files they correspond to. If the sums or signatures cannot be
confirmed, double check the command results and the download site address.
If those are OK, contact IBM AIX Security at security-alert@austin.ibm.com
and describe the discrepancy.

The interim fixes include prerequisite checking. This will ensure the
correct mapping between the interim fixes and AIX Technology Levels. The
following table shows the prerequisite fileset levels required for the
fixes above. The fileset levels listed are for bos.net.tcp.client.

Interim                    Fileset Level     Fileset Level
Fix                        (lower limit)     (upper limit)

IMPORTANT: If possible, it is recommended that a mksysb backup of the
system is created. Verify it is both bootable, and readable before

Customers may contact IBM support if any issues arise with these interim

Interim Installation Instructions:

These packages use the new Interim Fix Management Solution to install and
manage ifixes. More information can be found at:


To preview an epkg ifix installation execute the following command:

# emgr -e ipkg_name -p       # where ipkg_name is the name of the
                             # ifix package being previewed.

To install an epkg ifix package, execute the following command:

# emgr -e ipkg_name -X       # where ipkg_name is the name of the
                             # ifix package being installed.

The "X" flag will expand any filesystems if required.

C. Workaround

Remove the setuid bit from /usr/sbin/sliplogin. This can be done as

# chmod 555 /usr/sbin/sliplogin

Verify the changes:

# ls -la /usr/sbin/sliplogin
- - -r-xr-xr-x   1 root     system        15388 Aug  8 14:28 /usr/sbin/sliplogin

Note that this may prevent sliplogin from functioning normally for non-root

IV. Obtaining Fixes

AIX Version 5 APARs can be downloaded from:


Security related Interim Fixes can be downloaded from:


V.  Contact Information

If you would like to receive AIX Security Advisories via email, please


Comments regarding the content of this announcement can be directed to:


To request the PGP public key that can be used to communicate securely
with the AIX Security Team send email to security-alert@austin.ibm.com
with a subject of "get key". The key can also be downloaded from a PGP
Public Key Server. The key id is 0x1B14F299.

Please contact your local IBM AIX support center for any assistance.

eServer is a trademark of International Business Machines Corporation.
IBM, AIX and pSeries are registered trademarks of International Business
Machines Corporation. All other trademarks are property of their respective
Version: GnuPG v1.4.3 (GNU/Linux)


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