05 January 2015
Protect yourself against future threats.
-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 =========================================================================== AUSCERT External Security Bulletin Redistribution ESB-2015.0006 Multiple vulnerabilities in NTP suite 5 January 2015 =========================================================================== AusCERT Security Bulletin Summary --------------------------------- Product: ntp Publisher: FreeBSD Operating System: FreeBSD Impact/Access: Execute Arbitrary Code/Commands -- Remote/Unauthenticated Denial of Service -- Remote/Unauthenticated Provide Misleading Information -- Remote/Unauthenticated Reduced Security -- Remote/Unauthenticated Resolution: Patch/Upgrade CVE Names: CVE-2014-9296 CVE-2014-9295 CVE-2014-9294 CVE-2014-9293 Reference: ASB-2014.0145 ESB-2014.2519 ESB-2014.2497 ESB-2014.2476 ESB-2014.2473 ESB-2014.2472 Original Bulletin: ftp://ftp.freebsd.org/pub/FreeBSD/CERT/advisories/FreeBSD-SA-14:31.ntp.asc - --------------------------BEGIN INCLUDED TEXT-------------------- - -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA512 ============================================================================= FreeBSD-SA-14:31.ntp Security Advisory The FreeBSD Project Topic: Multiple vulnerabilities in NTP suite Category: contrib Module: ntp Announced: 2014-12-23 Affects: All supported versions of FreeBSD. Corrected: 2014-14-22 19:07:16 UTC (stable/10, 10.1-STABLE) 2014-12-23 22:56:01 UTC (releng/10.1, 10.1-RELEASE-p3) 2014-12-23 22:55:14 UTC (releng/10.0, 10.0-RELEASE-p15) 2014-14-22 19:08:09 UTC (stable/9, 9.3-STABLE) 2014-12-23 22:54:25 UTC (releng/9.3, 9.3-RELEASE-p7) 2014-12-23 22:53:44 UTC (releng/9.2, 9.2-RELEASE-p17) 2014-12-23 22:53:03 UTC (releng/9.1, 9.1-RELEASE-p24) 2014-14-22 19:08:09 UTC (stable/8, 8.4-STABLE) 2014-12-23 22:52:22 UTC (releng/8.4, 8.4-RELEASE-p21) CVE Name: CVE-2014-9293, CVE-2014-9294, CVE-2014-9295, CVE-2014-9296 For general information regarding FreeBSD Security Advisories, including descriptions of the fields above, security branches, and the following sections, please visit <URL:https://security.FreeBSD.org/>. I. Background The ntpd(8) daemon is an implementation of the Network Time Protocol (NTP) used to synchronize the time of a computer system to a reference time source. II. Problem Description When no authentication key is set in the configuration file, ntpd(8) would generate a random key that uses a non-linear additive feedback random number generator seeded with very few bits of entropy. [CVE-2014-9293] The ntp-keygen(8) utility is also affected by a similar issue. [CVE-2014-9294] When Autokey Authentication is enabled, for example if ntp.conf(5) contains a 'crypto pw' directive, a remote attacker can send a carefully crafted packet that can overflow a stack buffer. [CVE-2014-9295] In ntp_proto.c, the receive() function is missing a return statement in the case when an error is detected. [CVE-2014-9296] III. Impact The NTP protocol uses keys to implement authentication. The weak seeding of the pseudo-random number generator makes it easier for an attacker to brute-force keys, and thus may broadcast incorrect time stamps or masquerade as another time server. [CVE-2014-9293, CVE-2014-9294] An attacker may be able to utilize the buffer overflow to crash the ntpd(8) daemon or potentially run arbitrary code with the privileges of the ntpd(8) process, which is typically root. [CVE-2014-9295] IV. Workaround No workaround is available, but systems not running ntpd(8) are not affected. Because the issue may lead to remote root compromise, the FreeBSD Security Team recommends system administrators to firewall NTP ports, namely tcp/123 and udp/123 when it is not clear that all systems have been patched or have ntpd(8) stopped. V. Solution NOTE WELL: It is advisable to regenerate all keys used for NTP authentication, if configured. Perform one of the following: 1) Upgrade your vulnerable system to a supported FreeBSD stable or release / security branch (releng) dated after the correction date. 2) To update your vulnerable system via a binary patch: Systems running a RELEASE version of FreeBSD on the i386 or amd64 platforms can be updated via the freebsd-update(8) utility: # freebsd-update fetch # freebsd-update install 3) To update your vulnerable system via a source code patch: The following patches have been verified to apply to the applicable FreeBSD release branches. a) Download the relevant patch from the location below, and verify the detached PGP signature using your PGP utility. # fetch https://security.FreeBSD.org/patches/SA-14:31/ntp.patch # fetch https://security.FreeBSD.org/patches/SA-14:31/ntp.patch.asc # gpg --verify ntp.patch.asc b) Apply the patch. Execute the following commands as root: # cd /usr/src # patch < /path/to/patch c) Recompile the operating system using buildworld and installworld as described in <URL:https://www.FreeBSD.org/handbook/makeworld.html>. Restart the ntpd(8) daemons, or reboot the system. VI. Correction details The following list contains the correction revision numbers for each affected branch. Branch/path Revision - - ------------------------------------------------------------------------- stable/8/ r276073 releng/8.4/ r276154 stable/9/ r276073 releng/9.1/ r276155 releng/9.2/ r276156 releng/9.3/ r276157 stable/10/ r276072 releng/10.0/ r276158 releng/10.1/ r276159 - - ------------------------------------------------------------------------- To see which files were modified by a particular revision, run the following command, replacing NNNNNN with the revision number, on a machine with Subversion installed: # svn diff -cNNNNNN --summarize svn://svn.freebsd.org/base Or visit the following URL, replacing NNNNNN with the revision number: <URL:https://svnweb.freebsd.org/base?view=revision&revision=NNNNNN> VII. References <URL:https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2014-9293> <URL:https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2014-9294> <URL:https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2014-9295> <URL:https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2014-9296> <URL:https://www.kb.cert.org/vuls/id/852879> The latest revision of this advisory is available at <URL:https://security.FreeBSD.org/advisories/FreeBSD-SA-14:31.ntp.asc> - -----BEGIN PGP SIGNATURE----- iQIcBAEBCgAGBQJUmfSAAAoJEO1n7NZdz2rnV/IQAMeAuVbyKDMu3mec0ErpL5z8 OcSxVxKWH9udDJQkpiw6OaU4ks7PGOH/PgAad0mIhWPflXtpUlWMQtUa54Ds4s/t NjknM2vS4sBMZLk0Poqsts0TohfwdxF+CT8OCZARA2i3t70Ov0Y9BeoCatL2rnS+ rPbhhlnQXrsAJDCKcjSrYw+37cDNEdcvk4UKhiKh76J6CXwn2cT6h1dXTMFyImWq slTNlkJV6iFMNYn3oSA8nCVEJVMw2XQwVfg2qzkpZcuDGKE5fFpdvX3VcRP7b2cq zwSClt29B7FF3EjrplRuEdgxDk8m9PjVbUz9tocLPIqV0RjhTA9j7MhNcWH5G3Dh u6NQDsA0WzE8Ki2mrWpTEAFp21ZzSyXXtZ703XYiXbQKNG9lKEFv5Z8ffVHSrUT7 uB2BsP+LrnnWNNdjkRSSSxrfy4CvFLsdQ9FI1FNz+oofEio6yPO+W47pBH//Nbj0 wfeReW1OlbrtWF6NHZr4CfX+Lx9hu4CXXdXRWKdMDTYUywr0V6BiIsrNlN1z7XCy 90+43twFhGBsOSVD5PpcDmt9oEYfpwWKdXO6dXClCo+mxAki/fgf5Y24cTT9DTQn CKuVZuyaMi+HZ0jf2sKITQ03S8+Nrn7cZEXkIGScfT5z1Y8pcN+7bRhB1DpaCs0q IIw6TjJXQm8DTMuBIwf3 =oSCq - -----END PGP SIGNATURE----- - --------------------------END INCLUDED TEXT-------------------- You have received this e-mail bulletin as a result of your organisation's registration with AusCERT. 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It may not be updated when updates to the original are made. If downloading at a later date, it is recommended that the bulletin is retrieved directly from the author's website to ensure that the information is still current. Contact information for the authors of the original document is included in the Security Bulletin above. If you have any questions or need further information, please contact them directly. Previous advisories and external security bulletins can be retrieved from: http://www.auscert.org.au/render.html?cid=1980 =========================================================================== Australian Computer Emergency Response Team The University of Queensland Brisbane Qld 4072 Internet Email: firstname.lastname@example.org Facsimile: (07) 3365 7031 Telephone: (07) 3365 4417 (International: +61 7 3365 4417) AusCERT personnel answer during Queensland business hours which are GMT+10:00 (AEST). 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