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-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 =========================================================================== AUSCERT External Security Bulletin Redistribution ESB-2005.0596 -- FreeBSD-SA-05:18.zlib Buffer overflow in zlib 28 July 2005 =========================================================================== AusCERT Security Bulletin Summary --------------------------------- Product: zlib Publisher: FreeBSD Operating System: FreeBSD 5.4 and 5.3 Impact: Denial of Service Increased Privileges Access: Remote/Unauthenticated CVE Names: CAN-2005-1849 Ref: ESB-2005.0588 Original Bulletin: ftp://ftp.freebsd.org/pub/FreeBSD/CERT/Advisories/FreeBSD-SA-05:18.zlib.asc - --------------------------BEGIN INCLUDED TEXT-------------------- - -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 ============================================================================= FreeBSD-SA-05:18.zlib Security Advisory The FreeBSD Project Topic: Buffer overflow in zlib Category: core Module: libz Announced: 2005-07-27 Credits: Markus Oberhumer Affects: FreeBSD 5.3, FreeBSD 5.4 Corrected: 2005-07-27 08:41:44 UTC (RELENG_6, 6.0-BETA2) 2005-07-27 08:41:56 UTC (RELENG_5, 5.4-STABLE) 2005-07-27 08:42:16 UTC (RELENG_5_4, 5.4-RELEASE-p6) 2005-07-27 08:42:38 UTC (RELENG_5_3, 5.3-RELEASE-p20) CVE Name: CAN-2005-1849 For general information regarding FreeBSD Security Advisories, including descriptions of the fields above, security branches, and the following sections, please visit <URL:http://www.freebsd.org/security/>. NOTE WELL: The issue discussed in this advisory is distinct from the issue discussed in the earlier advisory FreeBSD-SA-05:16.zlib, although the impact is very similar. I. Background zlib is a compression library used by numerous applications to provide data compression/decompression routines. II. Problem Description A fixed-size buffer is used in the decompression of data streams. Due to erronous analysis performed when zlib was written, this buffer, which was belived to be sufficiently large to handle any possible input stream, is in fact too small. III. Impact A carefully constructed compressed data stream can result in zlib overwriting some data structures. This may cause applications to halt, resulting in a denial of service; or it may result in an attacker gaining elevated privileges. IV. Workaround No workaround is available. V. Solution Perform one of the following: 1) Upgrade your vulnerable system to 5-STABLE, or to the RELENG_5_4 or RELENG_5_3 security branch dated after the correction date. 2) To patch your present system: The following patches have been verified to apply to FreeBSD 5.3, and 5.4 systems. a) Download the relevant patch from the location below, and verify the detached PGP signature using your PGP utility. # fetch ftp://ftp.FreeBSD.org/pub/FreeBSD/CERT/patches/SA-05:18/zlib.patch # fetch ftp://ftp.FreeBSD.org/pub/FreeBSD/CERT/patches/SA-05:18/zlib.patch.asc b) Execute the following commands as root: # cd /usr/src # patch < /path/to/patch # cd /usr/src/lib/libz/ # make obj && make depend && make && make install VI. Correction details The following list contains the revision numbers of each file that was corrected in FreeBSD. Branch Revision Path - - ------------------------------------------------------------------------- RELENG_5 src/lib/libz/inftrees.h 1.1.1.5.2.1 RELENG_5_4 src/UPDATING 1.342.2.24.2.15 src/sys/conf/newvers.sh 1.62.2.18.2.11 src/lib/libz/inftrees.h 1.1.1.5.6.1 RELENG_5_3 src/UPDATING 1.342.2.13.2.23 src/sys/conf/newvers.sh 1.62.2.15.2.25 src/lib/libz/inftrees.h 1.1.1.5.4.1 RELENG_6 src/lib/libz/inftrees.h 1.1.1.5.8.1 - - ------------------------------------------------------------------------- VII. References http://www.cve.mitre.org/cgi-bin/cvename.cgi?name=CAN-2005-1849 The latest revision of this advisory is available at ftp://ftp.freebsd.org/pub/FreeBSD/CERT/advisories/FreeBSD-SA-05:18.zlib.asc - -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.1 (FreeBSD) iD4DBQFC50oLFdaIBMps37IRAg/1AJjTCluaNxJuBbSalLtgF34iey8DAJ9BGJmr 9NNdJfcjbm4qucvUYdsOqA== =XDop - -----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 If you believe that your computer system has been compromised or attacked in any way, we encourage you to let us know by completing the secure National IT Incident Reporting Form at: http://www.auscert.org.au/render.html?it=3192 =========================================================================== 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 iQCVAwUBQuhkYCh9+71yA2DNAQLFbwP+JqyScf/EdoJl4r1M/lkMtCAmjrECkhOM /OURma+ZmC6ty95Hu/qOT4hMEFIauC8Zp6x7WhMeOjvW9B9mCzIc9qi1j7WPyG8/ gIjwaNMQtIHK8Z7DPeyw/LABcDkZVvCHeCF0eVDp9i3NK26MEegR8rr4wU7ZvDX5 GKC2hee4rVc= =uRz2 -----END PGP SIGNATURE-----