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-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 =========================================================================== AUSCERT External Security Bulletin Redistribution ESB-2014.0869 ktrace kernel memory disclosure 4 June 2014 =========================================================================== AusCERT Security Bulletin Summary --------------------------------- Product: ktrace Publisher: FreeBSD Operating System: FreeBSD Impact/Access: Access Confidential Data -- Existing Account Resolution: Patch/Upgrade CVE Names: CVE-2014-3873 Original Bulletin: ftp://ftp.freebsd.org/pub/FreeBSD/CERT/advisories/FreeBSD-SA-14:12.ktrace.asc - --------------------------BEGIN INCLUDED TEXT-------------------- - -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA512 ============================================================================= FreeBSD-SA-14:12.ktrace Security Advisory The FreeBSD Project Topic: ktrace kernel memory disclosure Category: core Module: kern Announced: 2014-06-03 Credits: Jilles Tjoelker Affects: FreeBSD 8.4, FreeBSD 9.1 and FreeBSD 9.2 Corrected: 2014-06-03 19:02:33 UTC (stable/9, 9.3-BETA1) 2014-06-03 19:02:33 UTC (stable/9, 9.3-BETA1-p1) 2014-06-03 19:03:11 UTC (releng/9.2, 9.2-RELEASE-p7) 2014-06-03 19:03:11 UTC (releng/9.1, 9.1-RELEASE-p14) 2014-06-03 19:02:42 UTC (stable/8, 8.4-STABLE) 2014-06-03 19:03:23 UTC (releng/8.4, 8.4-RELEASE-p11) CVE Name: CVE-2014-3873 For general information regarding FreeBSD Security Advisories, including descriptions of the fields above, security branches, and the following sections, please visit <URL:http://security.FreeBSD.org/>. I. Background The ktrace utility enables kernel trace logging for the specified processes, commonly used for diagnostic or debugging purposes. The kernel operations that are traced include system calls, namei translations, signal processing, and I/O as well as data associated with these operations. The utility may be used only with a kernel that has been built with the ``KTRACE'' option in the kernel configuration file, which is enabled by default. II. Problem Description Due to an overlooked merge to -STABLE branches, the size for page fault kernel trace entries was set incorrectly. III. Impact A user who can enable kernel process tracing could end up reading the contents of kernel memory. Such memory might contain sensitive information, such as portions of the file cache or terminal buffers. This information might be directly useful, or it might be leveraged to obtain elevated privileges in some way; for example, a terminal buffer might include a user-entered password. IV. Workaround The system administrator may set sysctl security.bsd.unprivileged_proc_debug to 0 to prevent non-privileged users from using all process debugging facilities provided by the kernel, that includes ktrace functionality. Please note that this flag have broad effect and may break applications, as some of them may rely on certain debugging facilities to function. V. Solution 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 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 http://security.FreeBSD.org/patches/SA-14:12/ktrace.patch # fetch http://security.FreeBSD.org/patches/SA-14:12/ktrace.patch.asc # gpg --verify ktrace.patch.asc b) Apply the patch. Execute the following commands as root: # cd /usr/src # patch < /path/to/patch c) Recompile your kernel as described in <URL:http://www.FreeBSD.org/handbook/kernelconfig.html> and reboot the system. 3) 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 VI. Correction details The following list contains the correction revision numbers for each affected branch. Branch/path Revision - - ------------------------------------------------------------------------- stable/8/ r267016 releng/8.4/ r267019 stable/9/ r267015 releng/9.1/ r267018 releng/9.2/ r267018 - - ------------------------------------------------------------------------- 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:http://svnweb.freebsd.org/base?view=revision&revision=NNNNNN> VII. References <URL:http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2014-3873> The latest revision of this advisory is available at <URL:http://security.FreeBSD.org/advisories/FreeBSD-SA-14:12.ktrace.asc> - -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.22 (FreeBSD) iQIcBAEBCgAGBQJTjiDaAAoJEO1n7NZdz2rnIfQP/0kHBNvnNUiZ+1OWo5fMDg3N Oe7UdrvnfyeXlgw5bP4t0qwbTpn0kVYL2dfr3bxhkT1w7oF/xQjbcosx/DbzPZZs VtlAGQYh0CvOXcUZmh+COuRfcy2wkr1kKFlc2bGQVTq1uzKS+vceqA3619IWMnJO b6ClzFnn+0hk6BrUd8xdvoiYIF2RG+zcw7CxuoBQrzPYA9iO/S4ACmxzfTIgRcAD ZLGXfUEw3wlftfg605H1iV9xKm4FDUGr9qoL4W0UmYmmTmU4Z71yXSzX3A53qlRg Xd1Grw2K+zhaKaV6xL+mqox0nzSKiYuNf/ZguB5+x9ZA14ck7NtCYg6up1fgh7Ms pznVb8/GCc+IPdWJGXpSz6yFhl/MJc6mTOi+L0gOGvNKp0raNHelCpxlqavGt/tv 9Niv791FK32S8ynlP0yKRvd8Hzq4b185ehWuGWbQO8bEHljqhOyZDhysBYYWdgFi 0KG16lJopCbMPPPBVb4zfsFBvokr31m2w+/xsDD+hmaXa6C9bHIvHpuyJep4q02E 4NOoVr1x8dO5s7yVk7bNZx0WFCDYZ/DLMycLjEftHog7iq4nw29HW/Mt/rPgJWOf NiO0GEJ1XucJ1ShV/OC0B+69mFx9OsOI8kDNLE4l9oqGu2UqcZ/W0Dsa9PPl+ec+ njyksdL+yqvx9kF8fnJ0 =46Yf - -----END PGP SIGNATURE----- - --------------------------END INCLUDED TEXT-------------------- You have received this e-mail bulletin as a result of your organisation's registration with AusCERT. The mailing list you are subscribed to is maintained within your organisation, so if you do not wish to continue receiving these bulletins you should contact your local IT manager. If you do not know who that is, please send an email to auscert@auscert.org.au and we will forward your request to the appropriate person. NOTE: Third Party Rights This security bulletin is provided as a service to AusCERT's members. As AusCERT did not write the document quoted above, AusCERT has had no control over its content. The decision to follow or act on information or advice contained in this security bulletin is the responsibility of each user or organisation, and should be considered in accordance with your organisation's site policies and procedures. AusCERT takes no responsibility for consequences which may arise from following or acting on information or advice contained in this security bulletin. NOTE: This is only the original release of the security bulletin. 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: auscert@auscert.org.au 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). On call after hours for member emergencies only. =========================================================================== -----BEGIN PGP SIGNATURE----- Comment: http://www.auscert.org.au/render.html?it=1967 iQIVAwUBU45bVBLndAQH1ShLAQJHKw//T97gyZf0hald9oVMkgwxbte1sb35eJwD zXFzS0jZdUjUxxJL9IqcBD4M0jmO56SExsKq2znQwpciOC3kGMulPD2nfAmzYrZ3 P0N4OVTcSvtzofHpz/JYunQGSoKWgpIEXbHmYXEysv5j/2ljz0fwJZyfaLusziwB UQ0/FqrBMrj8iQkTc4RAJXZYwaG5SGzvRDivw8fjuWRNtmxR82dVXlymOQZe7Agw FX+dRImjOdaEZigbzaKWsUK06NKY31CZNsCh/QBUkNBt51GIl4634Y5uzeaNzU2E YcrO/OB2+HDe/H4u8oQf7HYgsDWLasoVLkRkHZcEnyPWSAAhXi3d+ftPgdGnz5AF AW1IGUE7NiTyIVqcQA7DTlVdz1DyH02U+3fIb3V79+BxWaJ/4eROCcE0EMpCbepe l+IVPKiPSbTTzeV4ILCE6Wvce7QC3NW0Kcu3HKkf0e/zet5JJ1bft1IfKExF9Zvu lOk6N9oHTYQ9IPkB0rb/J059ptYj36ih96+iPoL7WJkPmfmmX/Rei/AJaC8fpSl/ GG7zeqG/OwwGu4bmInASxUFBn5lIgqTupQqoCMtn/1RXFZoghYVI2T7dSzQawSsy B4gICwKuyQChgq4xzMSgTC9+FUbVOmcOyTo6Xh0YmT1E55BAk9HI91WA+fE7VE7R 0UlzCN1HuUc= =zwMv -----END PGP SIGNATURE-----