IBM SECURITY ADVISORY First Issued: Fri Aug 21 09:06:03 CDT 2015 |Updated: Mon Feb 15 13:19:18 CST 2016 |Update: Changed AIX 6.1.8 and 7.1.2 impacted levels. The most recent version of this document is available here: http://aix.software.ibm.com/aix/efixes/security/ntp_advisory3.asc https://aix.software.ibm.com/aix/efixes/security/ntp_advisory3.asc ftp://aix.software.ibm.com/aix/efixes/security/ntp_advisory3.asc Security Bulletin: Vulnerability in NTPv3 affects AIX (CVE-2015-1799) =============================================================================== SUMMARY: A vulnerability in NTPv3 affects AIX. =============================================================================== VULNERABILITY DETAILS: CVEID: CVE-2015-1799 DESCRIPTION: Network Time Protocol (NTP) Project NTP daemon (ntpd) is vulnerable to a denial of service, caused by an error when using symmetric key authentication. By sending specially-crafted packets to both peering hosts, an attacker could exploit this vulnerability to prevent synchronization. CVSS Base Score: 5.4 CVSS Temporal Score: See http://xforce.iss.net/xforce/xfdb/102052 for the current score. CVSS Environmental Score*: Undefined CVSS Vector: (AV:A/AC:M/Au:N/C:P/I:P/A:P) AFFECTED PRODUCTS AND VERSIONS: AIX 6.1, 7.1 VIOS 2.2.x The following AIX fileset levels are vulnerable: AIX Fileset Lower Level Upper Level KEY -------------------------------------------------------- | bos.net.tcp.client 6.1.0.0 6.1.8.20 key_w_fs bos.net.tcp.client 6.1.0.0 6.1.9.45 key_w_fs | bos.net.tcp.client 7.1.0.0 7.1.2.20 key_w_fs bos.net.tcp.client 7.1.0.0 7.1.3.45 key_w_fs AIX Fileset (VIOS) Lower Level Upper Level ------------------------------------------------------------ | bos.net.tcp.client 6.1.0.0(2.2.0.0) 6.1.8.19(2.2.2.70) bos.net.tcp.client 6.1.0.0(2.2.0.0) 6.1.9.45(2.2.3.50) 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: A. APARS IBM has assigned the following APARs to this problem: AIX Level APAR Availability SP KEY --------------------------------------------------- 6.1.9 IV73783 12/04/15 SP6 key_w_apar 7.1.3 IV74261 2/26/16 SP6 key_w_apar Subscribe to the APARs here: http://www.ibm.com/support/docview.wss?uid=isg1IV73783 http://www.ibm.com/support/docview.wss?uid=isg1IV74261 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/ntp_fix3.tar http://aix.software.ibm.com/aix/efixes/security/ntp_fix3.tar https://aix.software.ibm.com/aix/efixes/security/ntp_fix3.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. AIX Level Interim Fix (*.Z) KEY ------------------------------------------------ 6.1.8.6 IV74263s6a.150714.epkg.Z key_w_fix 6.1.9.5 IV73783s5a.150714.epkg.Z key_w_fix 7.1.2.6 IV74262s6a.150714.epkg.Z key_w_fix 7.1.3.5 IV74261s5a.150714.epkg.Z key_w_fix To extract the fixes from the tar file: tar xvf ntp_fix3.tar cd ntp_fix3 Verify you have retrieved the fixes intact: The checksums below were generated using the "openssl dgst -sha256 file" command as the followng: openssl dgst -sha256 filename KEY ----------------------------------------------------------------------------------------------------- 1b47c44eae7b3dd5d219586a5dafa806cd54c18872dbeee13774ae0f18242786 IV74263s6a.150714.epkg.Z key_w_csum ad3c3496796c9837ab7247a639e8d61e354d29c45daf940a39518f0ede5fe5ca IV73783s5a.150714.epkg.Z key_w_csum 785292432666ac70d019b31018965a03f3fcf8f870ec2a9473ec2e127a4a2f5f IV74262s6a.150714.epkg.Z key_w_csum 3ff500cc1235275a9ce1b66c9c0f41b94ccd500930dbc9d90a9e0dfe93364c14 IV74261s5a.150714.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 AIX Security at security-alert@austin.ibm.com and describe the discrepancy. openssl dgst -sha1 -verify -signature .sig openssl dgst -sha1 -verify -signature .sig Published advisory OpenSSL signature file location: http://aix.software.ibm.com/aix/efixes/security/ntp_advisory3.asc.sig https://aix.software.ibm.com/aix/efixes/security/ntp_advisory3.asc.sig ftp://aix.software.ibm.com/aix/efixes/security/ntp_advisory3.asc.sig 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 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. You should verify applying this configuration change does not cause any compatibility issues. If you change the default setting after applying the fix, you will expose yourself to the attack described above. IBM recommends that you review your entire environment to identify other areas where you have enabled the Diffie-Hellman key-exchange protocol used in TLS and take appropriate mitigation and remediation actions. WORKAROUNDS AND MITIGATIONS: None. =============================================================================== CONTACT US: If you would like to receive AIX Security Advisories via email, please visit "My Notifications": http://www.ibm.com/support/mynotifications To view previously issued advisories, please visit: http://www14.software.ibm.com/webapp/set2/subscriptions/onvdq Comments regarding the content of this announcement can be directed to: security-alert@austin.ibm.com To obtain the OpenSSL public key that can be used to verify the signed advisories and ifixes: Download the key from our web page: http://www.ibm.com/systems/resources/systems_p_os_aix_security_pubkey.txt To obtain the PGP public key that can be used to communicate securely with the AIX Security Team via security-alert@austin.ibm.com you can either: A. Download the key from our web page: http://www.ibm.com/systems/resources/systems_p_os_aix_security_pgppubkey.txt B. Download the key from a PGP Public Key Server. The key ID is: 0x28BFAA12 Please contact your local IBM AIX support center for any assistance. REFERENCES: Complete CVSS Guide: http://www.first.org/cvss/cvss-guide.html On-line Calculator V2: http://nvd.nist.gov/cvss.cfm?calculator&adv&version=2 ACKNOWLEDGEMENTS: None. CHANGE HISTORY: First Issued: Fri Aug 21 09:06:03 CDT 2015 | Updated: Mon Feb 15 13:19:18 CST 2016 | Update: Changed AIX 6.1.8 and 7.1.2 impacted levels. =============================================================================== *The CVSS Environment Score is customer environment specific and will ultimately impact the Overall CVSS Score. Customers can evaluate the impact of this vulnerability in their environments by accessing the links in the Reference section of this Security Bulletin. Disclaimer According to the Forum of Incident Response and Security Teams (FIRST), the Common Vulnerability Scoring System (CVSS) is an "industry open standard designed to convey vulnerability severity and help to determine urgency and priority of response." IBM PROVIDES THE CVSS SCORES "AS IS" WITHOUT WARRANTY OF ANY KIND, INCLUDING THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. CUSTOMERS ARE RESPONSIBLE FOR ASSESSING THE IMPACT OF ANY ACTUAL OR POTENTIAL SECURITY VULNERABILITY.