Security Bulletin: Vulnerability in sendmail impacts AIX (CVE-2014-3956)

Summary

There is a vulnerability in sendmail that impacts AIX.

Vulnerability Details

CVEID: CVE-2014-3956 **DESCRIPTION:**The sm_close_on_exec function in conf.c in sendmail before 8.14.9 has arguments in the wrong order, and consequently skips setting expected FD_CLOEXEC flags, which allows local users to access unintended high-numbered file descriptors via a custom mail-delivery program. **CVSS Base Score: **2.1 **CVSS Temporal Score:**See <https://exchange.xforce.ibmcloud.com/vulnerabilities/93592&gt; for the current score *CVSS Environmental Score:**Undefined CVSS Vector: (AV:L/AC:L/Au:N/C:N/I:P/A:N)

Affected Products and Versions

AIX 5.3, 6.1, 7.1, 7.2
VIOS 2.2

The following fileset levels are vulnerable:

key_fileset = aix

Fileset Lower Level Upper Level KEY
------------------------------------------------------------
bos.net.tcp.client 5.3.12.0 5.3.12.10 key_w_fs
bos.net.tcp.server 5.3.12.0 5.3.12.6 key_w_fs
bos.net.tcp.client 6.1.9.0 6.1.9.315 key_w_fs
bos.net.tcp.client 7.1.4.0 7.1.4.32 key_w_fs
bos.net.tcp.client 7.1.5.0 7.1.5.15 key_w_fs
bos.net.tcp.sendmail 7.2.0.0 7.2.0.3 key_w_fs
bos.net.tcp.sendmail 7.2.1.0 7.2.1.1 key_w_fs
bos.net.tcp.sendmail 7.2.2.0 7.2.2.15 key_w_fs

Note: To find out whether the affected filesets are installed on your systems, refer to the lslpp command found in AIX user’s guide.

Example: lslpp -L | grep -i bos.net.tcp.client

Remediation/Fixes

A. APARS

IBM has assigned the following APARs to this problem:

AIX Level APAR Availability SP KEY
------------------------------------------------
5.3.12 IJ03273 ** N/A key_w_apar
6.1.9 IJ02915 ** SP12 key_w_apar
7.1.4 IJ02917 ** SP7 key_w_apar
7.1.5 IJ03121 ** SP4 key_w_apar
7.2.0 IJ02918 ** N/A key_w_apar
7.2.1 IJ02919 ** SP5 key_w_apar
7.2.2 IJ02920 ** SP3 key_w_apar

** Please refer to AIX support lifecycle information page for availability of Service Packs:
<http://www-01.ibm.com/support/docview.wss?uid=isg3T1012517&gt;

Subscribe to the APARs here:

<http://www.ibm.com/support/docview.wss?uid=isg1IJ02915&gt;
<http://www.ibm.com/support/docview.wss?uid=isg1IJ02917&gt;
<http://www.ibm.com/support/docview.wss?uid=isg1IJ03121&gt;
<http://www.ibm.com/support/docview.wss?uid=isg1IJ02918&gt;
<http://www.ibm.com/support/docview.wss?uid=isg1IJ02919&gt;
<http://www.ibm.com/support/docview.wss?uid=isg1IJ02920&gt;

<https://www.ibm.com/support/docview.wss?uid=isg1IJ02915&gt;
<https://www.ibm.com/support/docview.wss?uid=isg1IJ02917&gt;
<https://www.ibm.com/support/docview.wss?uid=isg1IJ03121&gt;
<https://www.ibm.com/support/docview.wss?uid=isg1IJ02918&gt;
<https://www.ibm.com/support/docview.wss?uid=isg1IJ02919&gt;
<https://www.ibm.com/support/docview.wss?uid=isg1IJ02920&gt;

By subscribing, you will receive periodic email alerting you to the status of the APAR, and a link to download the fix once it becomes available.

B. FIXES

Fixes are available.

The fixes can be downloaded via ftp or http from:

<ftp://aix.software.ibm.com/aix/efixes/security/sendmail_fix3.tar&gt;
<http://aix.software.ibm.com/aix/efixes/security/sendmail_fix3.tar&gt;
<https://aix.software.ibm.com/aix/efixes/security/sendmail_fix3.tar&gt;

The links above are to a tar file containing this signed advisory, fix packages, and OpenSSL signatures for each package. The fixes below include prerequisite checking. This will enforce the correct mapping between the fixes and AIX Technology Levels.

Please note that the below table refers to AIX TL/SP level as opposed to fileset level, i.e., 7.1.4.5 is AIX 7100-04-05.

AIX Level Interim Fix (*.Z) KEY
----------------------------------------------
5.3.12.9 IJ03273s9a.180116.epkg.Z key_w_fix
6.1.9.9 IJ02915s9a.180110.epkg.Z key_w_fix
6.1.9.10 IJ02915s9a.180110.epkg.Z key_w_fix
6.1.9.11 IJ02915s9a.180110.epkg.Z key_w_fix
7.1.4.3 IJ02917s3a.180105.epkg.Z key_w_fix
7.1.4.4 IJ02917s3a.180105.epkg.Z key_w_fix
7.1.4.5 IJ02917s3a.180105.epkg.Z key_w_fix
7.1.5.0 IJ03121s0a.180110.epkg.Z key_w_fix
7.1.5.1 IJ03121s0a.180110.epkg.Z key_w_fix
7.1.5.2 IJ03121s0a.180110.epkg.Z key_w_fix
7.2.0.3 IJ02918s3a.180108.epkg.Z key_w_fix
7.2.0.4 IJ02918s3a.180108.epkg.Z key_w_fix
7.2.0.5 IJ02918s3a.180108.epkg.Z key_w_fix
7.2.0.6 IJ02918sp6.180913.epkg.Z key_w_fix
7.2.1.1 IJ02919s1a.180108.epkg.Z key_w_fix
7.2.1.2 IJ02919s1a.180108.epkg.Z key_w_fix
7.2.1.3 IJ02919s1a.180108.epkg.Z key_w_fix
7.2.2.0 IJ02920s0a.180110.epkg.Z key_w_fix
7.2.2.1 IJ02920s0a.180110.epkg.Z key_w_fix
7.2.2.2 IJ02920s0a.180110.epkg.Z key_w_fix

VIOS Level Interim Fix (*.Z) KEY
-----------------------------------------------
2.2.4.40 IJ02915s9a.180110.epkg.Z key_w_fix
2.2.4.50 IJ02915s9a.180110.epkg.Z key_w_fix
2.2.5.20 IJ02915s9a.180110.epkg.Z key_w_fix
2.2.5.30 IJ02915s9a.180110.epkg.Z key_w_fix
2.2.6.10 IJ02915s9a.180110.epkg.Z key_w_fix
2.2.6.20 IJ02915s9a.180110.epkg.Z key_w_fix
2.2.6.21 IJ02915s9a.180110.epkg.Z key_w_fix

To extract the fixes from the tar file:

tar xvf sendmail_fix3.tar
cd sendmail_fix3

Verify you have retrieved the fixes intact:

The checksums below were generated using the “openssl dgst -sha256 [filename]” command as the following:

openssl dgst -sha256 filename KEY
-----------------------------------------------------------------------------------------------------
2987f7b0b4c549c958f6919974adf104452f9179a4e004c5f862d2473e751dfc IJ02915s9a.180110.epkg.Z key_w_csum
fbb7fc0fcbb30d6ccd2e1761c4682cf7e0252aeb64e60493e12d48f6c44510b0 IJ02917s3a.180105.epkg.Z key_w_csum
a0e3e1fbf9f7015ef72ffe181c7995862fb9f52d901ae3d7b0e8a98ae0af7994 IJ02918s3a.180108.epkg.Z key_w_csum
9bbc538083702bd8bc574560d09b07c8dc061e07a14329dc1e6759ccba516f9c IJ02918sp6.180913.epkg.Z key_w_csum
bb2c7189784b734808aa637cf7ecfec5bd816cb42d9e5d812ac8e09abba6299d IJ02919s1a.180108.epkg.Z key_w_csum
4a907f461a36a1a63941b0cca8992b366d71197f7d47c63e425d5614ac072157 IJ02920s0a.180110.epkg.Z key_w_csum
4d95acdd312b233cedb5e106dfcdb8ac2266a11c402837545ea4963f929e7515 IJ03121s0a.180110.epkg.Z key_w_csum
6663891d15e91f5f316e4f73c2a7e0d23dca31df2508e98cd0cc06bb227da55b IJ03273s9a.180116.epkg.Z key_w_csum

These sums should match exactly. The OpenSSL signatures in the tar file and on this advisory can also be used to verify the integrity of the fixes. If the sums or signatures cannot be confirmed, contact IBM Support at <http://ibm.com/support/&gt; and describe the discrepancy.

openssl dgst -sha1 -verify [pubkey_file] -signature [advisory_file].sig [advisory_file]

openssl dgst -sha1 -verify [pubkey_file] -signature [ifix_file].sig [ifix_file]

Published advisory OpenSSL signature file location:

<http://aix.software.ibm.com/aix/efixes/security/sendmail_advisory3.asc.sig&gt;
<https://aix.software.ibm.com/aix/efixes/security/sendmail_advisory3.asc.sig&gt;
<ftp://aix.software.ibm.com/aix/efixes/security/sendmail_advisory3.asc.sig&gt;

C. FIX AND INTERIM FIX INSTALLATION

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

To preview a fix installation:

installp -a -d fix_name -p all # where fix_name is the name of the
# fix package being previewed.

To install a fix package:

installp -a -d fix_name -X all # where fix_name is the name of the
# fix package being installed.

Interim fixes have had limited functional and regression testing but not the full regression testing that takes place for Service Packs; however, IBM does fully support them.

Interim fix management documentation can be found at:

<http://www14.software.ibm.com/webapp/set2/sas/f/aix.efixmgmt/home.html&gt;
<https://www14.software.ibm.com/webapp/set2/sas/f/aix.efixmgmt/home.html&gt;

To preview an interim fix installation:

emgr -e epkg_name -p # where epkg_name is the name of the
# interim fix package being previewed.

To install an interim fix package:

emgr -e epkg_name -X # where epkg_name is the name of the
# interim fix package being installed.

Workarounds and Mitigations

None.