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-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 =========================================================================== AUSCERT External Security Bulletin Redistribution ESB-2014.2059 Kernel stack disclosure in setlogin(2) / getlogin(2) 5 November 2014 =========================================================================== AusCERT Security Bulletin Summary --------------------------------- Product: setlogin Publisher: FreeBSD Operating System: FreeBSD Impact/Access: Access Privileged Data -- Existing Account Resolution: Patch/Upgrade CVE Names: CVE-2014-8476 Original Bulletin: http://security.FreeBSD.org/advisories/FreeBSD-SA-14:25.setlogin.asc - --------------------------BEGIN INCLUDED TEXT-------------------- - -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA512 ============================================================================= FreeBSD-SA-14:25.setlogin Security Advisory The FreeBSD Project Topic: Kernel stack disclosure in setlogin(2) / getlogin(2) Category: core Module: kernel Announced: 2014-11-04 Credits: Mateusz Guzik Affects: All supported versions of FreeBSD. Corrected: 2014-11-04 23:29:57 UTC (stable/10, 10.1-PRERELEASE) 2014-11-04 23:34:46 UTC (releng/10.1, 10.1-RC4-p1) 2014-11-04 23:34:46 UTC (releng/10.1, 10.1-RC3-p1) 2014-11-04 23:34:46 UTC (releng/10.1, 10.1-RC2-p3) 2014-11-04 23:31:17 UTC (releng/10.0, 10.0-RELEASE-p12) 2014-11-04 23:30:47 UTC (stable/9, 9.3-STABLE) 2014-11-04 23:33:46 UTC (releng/9.3, 9.3-RELEASE-p5) 2014-11-04 23:33:17 UTC (releng/9.2, 9.2-RELEASE-p15) 2014-11-04 23:32:45 UTC (releng/9.1, 9.1-RELEASE-p22) 2014-11-04 23:30:23 UTC (stable/8, 8.4-STABLE) 2014-11-04 23:32:15 UTC (releng/8.4, 8.4-RELEASE-p19) CVE Name: CVE-2014-8476 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 setlogin(2) system call sets the login name of the user associated with the current session. The getlogin(2) routine returns the login name of the user associated with the current session, as previously set by setlogin(2). II. Problem Description When setlogin(2) is called while setting up a new login session, the login name is copied into an uninitialized stack buffer, which is then copied into a buffer of the same size in the session structure. The getlogin(2) system call returns the entire buffer rather than just the portion occupied by the login name associated with the session. III. Impact An unprivileged user can access this memory by calling getlogin(2) and reading beyond the terminating NUL character of the resulting string. Up to 16 (FreeBSD 8) or 32 (FreeBSD 9 and 10) bytes of kernel memory may be leaked in this manner for each invocation of setlogin(2). This memory may contain sensitive information, such as portions of the file cache or terminal buffers, which an attacker might leverage to obtain elevated privileges. 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. 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. [FreeBSD 9.1] # fetch http://security.FreeBSD.org/patches/SA-14:25/setlogin-91.patch # fetch http://security.FreeBSD.org/patches/SA-14:25/setlogin-91.patch.asc # gpg --verify setlogin-91.patch.asc [All other versions] # fetch http://security.FreeBSD.org/patches/SA-14:25/setlogin.patch # fetch http://security.FreeBSD.org/patches/SA-14:25/setlogin.patch.asc # gpg --verify setlogin.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. VI. Correction details The following list contains the correction revision numbers for each affected branch. Branch/path Revision - - ------------------------------------------------------------------------- stable/8/ r274108 releng/8.4/ r274111 stable/9/ r274109 releng/9.1/ r274112 releng/9.2/ r274113 releng/9.3/ r274114 stable/10/ r274107 releng/10.0/ r274110 releng/10.1/ r274115 - - ------------------------------------------------------------------------- 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-2014-8476> The latest revision of this advisory is available at <URL:http://security.FreeBSD.org/advisories/FreeBSD-SA-14:25.setlogin.asc> - -----BEGIN PGP SIGNATURE----- iQIcBAEBCgAGBQJUWWUQAAoJEO1n7NZdz2rnI0IP/RlwFhOJgr9CHdKg5SYsruSQ LG6z0ufgUETIkeXP1KGm6oYz0X8hpU2Q+MIE5urrPbGYL4Ouo/1oCiwGkBPh4xM/ L2Z/qIBxmfG/NaRK8PnGSXzlCc02XGnqf9Y6CJN1sIkwrptop02y9sgaLsqLy7K6 s/YvQ1fe5FT6TV9Nr9l6OwKkVAYa1Ba+JUnklVBWA2eZkLa6YOUlY25w9alqTMVQ Z4oaLHCnGradKdaKKk0NOOYv0ZGHjkp/Lwd9ja8wyW0K+R1aef9Z5tWloVWQBeJ8 gzxeA/JpfRtb0lYj2GIpny6znP/lzkEve42No6xDdmUr4Wp0b5hN2qGgwwgEFSIo 2kFVwMkRlK1JsD0U+VK8AxP4neJFECw3t0zWTUr3BMnxoOEG6O1nIU0T6Ru8/K0b aIc/G8TiOxOaXHuiWJhR1p9cblGlz7HnFSAmM6vN0O4DBcX7xwr/ndDl/6npvkmt biB+hXZK0Ega8X9LsZ5injDo0FZ4XNIyEOy4/QOeJW4kJQv0Oh14cYSU6cM/yfaU tJ7M6WYnFS8G+0e03auM1XVeu2oxyR0ry1IC7xS4O9N4m+8nE7DlRU8okhQRXiFB iCmzO1XmOTK0zygtS34bDaOuey3U0yFG4O5wMKrAkMeQ9jPogyt99ZzIk3L3UPqZ xcWRhKahyz9umrzsssOL =xiWR - -----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: 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 iQIVAwUBVFmHPhLndAQH1ShLAQKSCA//Uht4HebvIhtq4Nf3ePf9nI8szu23FxLY 5nAL3sKpUKFXhcxSxnCbicme+ALPx9eyEPUYayym7g65AzeYdDY0gJOvCvm5PHQG KWxfXczaWdiSFXhEXH34PZ8J6Wcw6terivJTeDD4RVgE37GDFvV93/puHnLp6QwM 1cmkNwXxsHB8hcuJ2KN6dgHmKF7MuCATYhYxcsHdvw7Mv3EhYKxLoLb53vKu8Ank wfiBdh7i4R864T3AHx0X9fN+y5oFDIyeIa4pT0+B8y/U14RVVYHgFpyOoRUBUrA0 clY2qxHxYOueL+T4IEo5is6C2b7Loum6IvqGzAaKGO0cA3+VtUl1S+3ivWu8/BF7 S5xXQbWZoz64YDLWHnraPxcVIwqRw1223VieFfylY0LlqtXR3vlFMnRrUh2QCX7f xpYi9xanTjc/hcJrPsgRn9mns/FTtNlimdjXZtSmZyVwEHVVUyOs+X1XAKPYC+CK 3Wn3XJ4SMj2QlVanFjcSTi5JXCIGnLeeRvg9hx55suelgMqQ+jQIeJWhi+U3uLWV u1IF1EQh268nTzdTFeUtqGIJRr5aIVHF2ORNesQEOUwfV3SGfUbXwGlvjtfQ9652 jbqwBCoudWCeMU3ggvGqnU+DrOJ8cagbYPnMhbEqXa2Oxf2YfhveCEpo69J7pVMi XlL1Jtjj/cs= =AdUa -----END PGP SIGNATURE-----