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-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA256 =========================================================================== AUSCERT External Security Bulletin Redistribution ESB-2017.2911 Kernel data leak via ptrace(PT_LWPINFO) 16 November 2017 =========================================================================== AusCERT Security Bulletin Summary --------------------------------- Product: ptrace Publisher: FreeBSD Operating System: FreeBSD Impact/Access: Access Privileged Data -- Existing Account Resolution: Patch/Upgrade CVE Names: CVE-2017-1086 Original Bulletin: https://security.freebsd.org/advisories/FreeBSD-SA-17:08.ptrace.asc Comment: This advisory references vulnerabilities in products which run on platforms other than FreeBSD. It is recommended that administrators running ptrace check for an updated version of the software for their operating system. - --------------------------BEGIN INCLUDED TEXT-------------------- - -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA512 ============================================================================= FreeBSD-SA-17:08.ptrace Security Advisory The FreeBSD Project Topic: Kernel data leak via ptrace(PT_LWPINFO) Category: core Module: ptrace Announced: 2017-11-15 Credits: John Baldwin Affects: All supported versions of FreeBSD. Corrected: 2017-11-10 12:28:43 UTC (stable/11, 11.1-STABLE) 2017-11-15 22:39:41 UTC (releng/11.1, 11.1-RELEASE-p4) 2017-11-15 22:40:15 UTC (releng/11.0, 11.0-RELEASE-p15) 2017-11-10 12:31:58 UTC (stable/10, 10.4-STABLE) 2017-11-15 22:40:32 UTC (releng/10.4, 10.4-RELEASE-p3) 2017-11-15 22:40:46 UTC (releng/10.3, 10.3-RELEASE-p24) CVE Name: CVE-2017-1086 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 ptrace(2) syscall provides the facility for a debugger to control the execution of the target process and to obtain necessary status information about it. The struct ptrace_lwpinfo structure is reported by one of the ptrace(2) subcommand and contains a lot of the information about the stopped thread (light-weight process or LWP, thus the name). II. Problem Description Not all information in the struct ptrace_lwpinfo is relevant for the state of any thread, and the kernel does not fill the irrelevant bytes or short strings. Since the structure filled by the kernel is allocated on the kernel stack and copied to userspace, a leak of information of the kernel stack of the thread is possible from the debugger. III. Impact Some bytes from the kernel stack of the thread using ptrace(PT_LWPINFO) call can be observed in userspace. IV. Workaround No workaround is available. 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. Afterward, reboot the system. 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 Afterward, reboot the system. 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-17:08/ptrace.patch # fetch https://security.FreeBSD.org/patches/SA-17:08/ptrace.patch.asc # gpg --verify ptrace.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:https://www.FreeBSD.org/handbook/kernelconfig.html> and reboot the system. VI. Correction details The following list contains the correction revision numbers for each affected branch. Branch/path Revision - - ------------------------------------------------------------------------- stable/10/ r325643 releng/10.3/ r325871 releng/10.4/ r325870 stable/11/ r325642 releng/11.0/ r325869 releng/11.1/ r325868 - - ------------------------------------------------------------------------- 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-2017-1086> The latest revision of this advisory is available at <URL:https://security.FreeBSD.org/advisories/FreeBSD-SA-17:08.ptrace.asc> - -----BEGIN PGP SIGNATURE----- iQKTBAEBCgB9FiEEHPf/b631yp++G4yy7Wfs1l3PaucFAloMxftfFIAAAAAALgAo aXNzdWVyLWZwckBub3RhdGlvbnMub3BlbnBncC5maWZ0aGhvcnNlbWFuLm5ldDFD RjdGRjZGQURGNUNBOUZCRTFCOENCMkVENjdFQ0Q2NURDRjZBRTcACgkQ7Wfs1l3P audQ+hAA2+cjqNVUJ/Polwo9cu61QxKLEXO1DItlMIFWBxpFpXXlRSLbqH+RGmaO 6aR4Q1xcOnLm8e57KcLFppl77uOZyO0IJ0lyK6P30ouSxuYIW3aHbW+p3pVYBE+J aqF3mNxSh9xQRgXvxUB/CM3w/SMKkxXtkZMvhNSGFCShGQTNpjGfAgIwOZD8mNFi WvYbPgzwfeE4tsaStZ91SZ8wf2nxdRXhybDXEOCAJvicP6IqYA1Zfr7RG2N3swK7 JKLXW7tiVu+zbRYYFiWYX4FIWatIlsTjpD0GyuZs0j2PCEu80z1muFnrp/dGg3Bn APGVzIrkFjKvmXfkuFZFPMWCL+u9cUgOMNGkMFDXrLppLL7aXCGrz3BWECg581Pr dnUrrz/iEcXGDcnTJ3Ff+OidqdhdpVQz59Ek90TMd5iO+nZ+xeVjVzxdLHb82/wt KlgXRpwTg3Q72xDSF84UmRSkk1M/V5AZMrZiy2RjIwtvLqIJ9ZpLAMnrwTTWRDjB YurHHNWKjMVkdKCdbpBVGRjNmS6XYS6QukmA4M85d2r0Dmb8J6Gd6juHc3Essrz+ 3qEMKAcYsSWbQ5ZSMywUOzM74Dk+wUTf7jCJ1IsSqn8hYHOqvUSF0ftwXkdS1+cv GT25iduAMCdTP15Qp57Wlhv9WCF8eOUoYKHiSpXcVa6XMqazLy4= =Uqz2 - -----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: https://www.auscert.org.au/bulletins/ =========================================================================== 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). 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