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-----BEGIN PGP SIGNED MESSAGE----- =========================================================================== AUSCERT External Security Bulletin Redistribution ESB-2003.0656 -- NetBSD Security Advisory 2003-013 Kernel memory disclosure via ibcs2 19 September 2003 =========================================================================== AusCERT Security Bulletin Summary --------------------------------- Product: kernel Publisher: NetBSD Operating System: NetBSD-current prior to August 7, 2002 NetBSD 1.6.1 NetBSD 1.6 NetBSD-1.5.3 NetBSD-1.5.2 NetBSD-1.5.1 NetBSD-1.5 Impact: Access Privileged Data Access Required: Existing Account - --------------------------BEGIN INCLUDED TEXT-------------------- - -----BEGIN PGP SIGNED MESSAGE----- NetBSD Security Advisory 2003-013 ================================= Topic: Kernel memory disclosure via ibcs2 Version: NetBSD-current: source prior to August 7, 2002 NetBSD 1.6.1: not affected NetBSD 1.6: not affected NetBSD-1.5.3: affected NetBSD-1.5.2: affected NetBSD-1.5.1: affected NetBSD-1.5: affected Severity: Fixed: NetBSD-current: August 7, 2002 NetBSD-1.6 branch: not affected NetBSD-1.5 branch: August 28, 2002 Abstract ======== The iBCS2 system call translator for statfs(2) erroneously used the user-supplied length parameter when copying a kernel data structure into userland. If the length parameter were larger than required, then instead of copying only the statfs-related data structure, additional kernel memory would also be made available to the user. Technical Details ================= If iBCS2 support were enabled, a malicious user could call the iBCS2 version of statfs(2) with an arbitrarily large length parameter, causing the kernel to return a large portion 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. iBCS2 support is only present on i386/vax GENERIC kernel. Solutions and Workarounds ========================= If your kernel configuration file does not contain COMPAT_IBCS2, your system is not affected. The following instructions describe how to upgrade your kernel binaries by updating your source tree and rebuilding and installing a new version of kernel. * NetBSD-current: Systems running NetBSD-current dated from before 2002-08-06 should be upgraded to NetBSD-current dated 2002-08-07 or later. The following directories need to be updated from the netbsd-current CVS branch (aka HEAD): src/sys/compat/ibcs2/ibcs2_stat.c However, because the date of the point fix is way too old, we'd suggest you to update the whole kernel. The following instruction is for updating the whole kernel. To update from CVS, re-build, and re-install the kernel and reboot: # cd src # cvs update -d -P sys # cd sys/ARCH/conf # config KERNELCONF # cd ../../compile/KERNELCONF # make depend; make # cp netbsd / # reboot * NetBSD 1.6, 1.6.1: The binary distribution of NetBSD 1.6 and 1.6.1 are NOT vulnerable. * NetBSD 1.5, 1.5.1, 1.5.2, 1.5.3: The binary distribution of NetBSD 1.5 to 1.5.3 are vulnerable. Systems running NetBSD 1.5, 1.5.1, 1.5.2, or 1.5.3 sources dated from before 2003-08-27 should be upgraded from NetBSD 1.5.* sources dated 2003-08-28 or later. The following directories need to be updated from the netbsd-1-5 CVS branch: src/sys/compat/ibcs2/ibcs2_stat.c To update from CVS, re-build, and re-install the kernel and reboot: # cd src # cvs update -d -P -r netbsd-1-5 sys/compat/ibcs2/ibcs2_stat.c # cd sys/ARCH/conf # config KERNELCONF # cd ../../compile/KERNELCONF # make depend; make # cp netbsd / # reboot Alternatively, apply the following patch (with potential offset differences): ftp://ftp.NetBSD.org/pub/NetBSD/security/patches/SA2003-013-ibcs2.patch To patch, re-build and re-install re-install the kernel and reboot: # cd src/sys/compat/ibcs2 # patch < /path/to/SA2003-013-ibcs2.patch # make cleandir dependall # make install Thanks To ========= Some of the text are derived from FreeBSD security advisory FreeBSD-SA-03:10.ibcs2. The problem in ibcs2_stat.c was pointed out by silvio@qualys.com. Revision History ================ 2003-09-17 Initial release More Information ================ Advisories may be updated as new information becomes available. The most recent version of this advisory (PGP signed) can be found at ftp://ftp.NetBSD.org/pub/NetBSD/security/advisories/NetBSD-SA2003-013.txt.asc Information about NetBSD and NetBSD security can be found at http://www.NetBSD.org/ and http://www.NetBSD.org/Security/. Copyright 2003, The NetBSD Foundation, Inc. All Rights Reserved. Redistribution permitted only in full, unmodified form. $NetBSD: NetBSD-SA2003-013.txt,v 1.4 2003/09/17 02:47:19 david Exp $ - -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.0.6 (NetBSD) Comment: For info see http://www.gnupg.org iQCVAwUBP2fWJj5Ru2/4N2IFAQE9wAP/TGHBn/CeZwH3XnVRmc3ef46Za7mKv4Q2 xut0DVEwoVBNadCdBjsBmjivRC48U7fTDu5G/tv2c9innL34Uwt0hwh0skybyKQg BtrPUJv8ytf9VhkiuHZBc+Vl/VCLS1RhbGelyHje3JcXJRkgB3i3B6WsomzS8YSQ bJrlaSxPHc4= =XK3L - -----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. 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On call after hours for member emergencies only. -----BEGIN PGP SIGNATURE----- Comment: http://www.auscert.org.au/render.html?it=1967 iQCVAwUBP2qReyh9+71yA2DNAQEvegP+KTQ3JbzzxmOSG/TnZupnYbyefr5qdTxA OHgLTuGFLhvDiXGfDr0tDD5Jw8ykpXQYjcgQ++45f2yp7ghfhlz73t3HPKe5K6FI LOk3Cf5Uv6AnlM4+EDsT2uxNnfZqD8cCvNR8znUCqB1gca+0STBn6kyKCQZoTNqW ee3LPGD9lP4= =NXyl -----END PGP SIGNATURE-----