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ibmIBM96C5919463DAD2E3879FA850ED95011B03066BD4FBBE6EE79C85D5AF674ACB5E
HistoryDec 14, 2018 - 6:25 p.m.

Security Bulletin: Vulnerabilities in NTPv4 affect AIX (CVE-2018-12327, CVE-2018-7170)

2018-12-1418:25:01
www.ibm.com
9

9.8 High

CVSS3

Attack Vector

NETWORK

Attack Complexity

LOW

Privileges Required

NONE

User Interaction

NONE

Scope

UNCHANGED

Confidentiality Impact

HIGH

Integrity Impact

HIGH

Availability Impact

HIGH

CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

7.5 High

CVSS2

Access Vector

NETWORK

Access Complexity

LOW

Authentication

NONE

Confidentiality Impact

PARTIAL

Integrity Impact

PARTIAL

Availability Impact

PARTIAL

AV:N/AC:L/Au:N/C:P/I:P/A:P

Summary

There is a vulnerability in NTPv4 that affects AIX.

Vulnerability Details

NTPv4 is vulnerable to:

CVEID: CVE-2018-12327 DESCRIPTION: NTP is vulnerable to a stack-based buffer overflow, caused by improper bounds checking by ntpq and ntpdc. By sending an overly long string argument, a local attacker could overflow a buffer and execute arbitrary code on the system with elevated privileges or cause the application to crash.
CVSS Base Score: 5.9
CVSS Temporal Score: See <https://exchange.xforce.ibmcloud.com/vulnerabilities/145120&gt; for the current score
CVSS Environmental Score*: Undefined
CVSS Vector: (CVSS:3.0/AV:L/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L)

CVEID: CVE-2018-7170 DESCRIPTION: NTP could allow a remote authenticated attacker to bypass security restrictions, caused by a Sybil attack. By creating many ephemeral associations, an attacker could exploit this vulnerability to win the clock selection of ntpd and modify a victim’s clock.
CVSS Base Score: 3.1
CVSS Temporal Score: See <https://exchange.xforce.ibmcloud.com/vulnerabilities/139786&gt; for the current score
CVSS Environmental Score*: Undefined
CVSS Vector: (CVSS:3.0/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:L/A:N)

Affected Products and Versions

AIX 6.1, 7.1, 7.2
VIOS 2.2.x

The vulnerabilities in the following filesets are being addressed:

key_fileset = aix

For NTPv4:

Fileset Lower Level Upper Level KEY
---------------------------------------------------------
ntp.rte 7.4.2.8100 7.4.2.8110 key_w_fs

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 ntp.rte

Remediation/Fixes

FIXES

AIX and VIOS fixes are available.

The AIX/VIOS fixes can be downloaded via ftp or http from:

ftp://aix.software.ibm.com/aix/efixes/security/ntp_fix11.tar
http://aix.software.ibm.com/aix/efixes/security/ntp_fix11.tar
https://aix.software.ibm.com/aix/efixes/security/ntp_fix11.tar

The link above is 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.

For NTPv4:

AIX Level Interim Fix (*.Z) KEY
----------------------------------------------
6.1.x IJ10280s3b.181206.epkg.Z key_w_fix
7.1.x IJ10280s3b.181206.epkg.Z key_w_fix
7.2.x IJ10280s3b.181206.epkg.Z key_w_fix

VIOS Level Interim Fix (*.Z) KEY
-----------------------------------------------
2.2.x IJ10280s3b.181206.epkg.Z key_w_fix

To extract the fixes from the tar file:

tar xvf ntp_fix11.tar
cd ntp_fix11

Verify you have retrieved the fixes intact:

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

openssl dgst -sha256 filename KEY
-----------------------------------------------------------------------------------------------------
000891c62f5e59c34909399d0ef4c74c72048a4fc1e7e50b66dedaa4fcf0ee87 IJ10280s3b.181206.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/ 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/ntp_advisory11.asc.sig
https://aix.software.ibm.com/aix/efixes/security/ntp_advisory11.asc.sig
ftp://aix.software.ibm.com/aix/efixes/security/ntp_advisory11.asc.sig

FIX AND INTERIM FIX INSTALLATION

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

The fix will not take affect until any running xntpd servers have been stopped and restarted with the following commands:

stopsrc -s xntpd
startsrc -s xntpd

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.

After installation the ntp daemon must be restarted:

stopsrc -s xntpd
startsrc -s xntpd

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

To preview an interim fix installation:

emgr -e ipkg_name -p # where ipkg_name is the name of the

interim fix package being previewed.

To install an interim fix package:

emgr -e ipkg_name -X # where ipkg_name is the name of the

interim fix package being installed.

Workarounds and Mitigations

None.

CPENameOperatorVersion
aixeq6.1
aixeq7.1
aixeq7.2

9.8 High

CVSS3

Attack Vector

NETWORK

Attack Complexity

LOW

Privileges Required

NONE

User Interaction

NONE

Scope

UNCHANGED

Confidentiality Impact

HIGH

Integrity Impact

HIGH

Availability Impact

HIGH

CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

7.5 High

CVSS2

Access Vector

NETWORK

Access Complexity

LOW

Authentication

NONE

Confidentiality Impact

PARTIAL

Integrity Impact

PARTIAL

Availability Impact

PARTIAL

AV:N/AC:L/Au:N/C:P/I:P/A:P

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