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-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 =========================================================================== AUSCERT External Security Bulletin Redistribution ESB-2006.0222 -- [FreeBSD] IPsec replay attack vulnerability 23 March 2006 =========================================================================== AusCERT Security Bulletin Summary --------------------------------- Product: ipsec Publisher: FreeBSD Operating System: FreeBSD after 4.8-RELEASE Impact: Reduced Security Access: Remote/Unauthenticated CVE Names: CVE-2006-0905 Original Bulletin: ftp://ftp.freebsd.org/pub/FreeBSD/CERT/advisories/FreeBSD-SA-06:11.ipsec.asc - --------------------------BEGIN INCLUDED TEXT-------------------- - -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 ============================================================================= FreeBSD-SA-06:11.ipsec Security Advisory The FreeBSD Project Topic: IPsec replay attack vulnerability Category: core Module: sys_netipsec Announced: 2006-03-22 Credits: Pawel Jakub Dawidek Affects: All FreeBSD releases since 4.8-RELEASE Corrected: 2006-03-22 16:01:08 UTC (RELENG_6, 6.1-STABLE) 2006-03-22 16:01:38 UTC (RELENG_6_0, 6.0-RELEASE-p6) 2006-03-22 16:01:56 UTC (RELENG_5, 5.5-STABLE) 2006-03-22 16:02:17 UTC (RELENG_5_4, 5.4-RELEASE-p13) 2006-03-22 16:02:35 UTC (RELENG_5_3, 5.3-RELEASE-p28) 2006-03-22 16:02:49 UTC (RELENG_4, 4.11-STABLE) 2006-03-22 16:03:05 UTC (RELENG_4_11, 4.11-RELEASE-p16) 2006-03-22 16:03:25 UTC (RELENG_4_10, 4.10-RELEASE-p22) CVE Name: CVE-2006-0905 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/>. I. Background IPsec is a set of protocols, including ESP (Encapsulating Security Payload) and AH (Authentication Header), that provide security services for IP datagrams. ESP protects IP payloads from wire-tapping by encrypting them using secret key cryptography algorithms. AH guarantees the integrity of IP packets and protects them from intermediate alteration or impersonation by attaching a cryptographic checksum computed using one-way hash functions. II. Problem Description IPsec provides an anti-replay service which when enabled prevents an attacker from successfully executing a replay attack. This is done through the verification of sequence numbers. A programming error in the fast_ipsec(4) implementation results in the sequence number associated with a Security Association not being updated, allowing packets to unconditionally pass sequence number verification checks. III. Impact An attacker able to to intercept IPSec packets can replay them. If higher level protocols which do not provide any protection against packet replays (e.g., UDP) are used, this may have a variety of effects. IV. Workaround No workaround is available. V. Solution Perform one of the following: 1) Upgrade your vulnerable system to 4-STABLE, 5-STABLE, or 6-STABLE, or to the RELENG_6_0, RELENG_5_4, RELENG_5_3, RELENG_4_11, or RELENG_4_10 security branch dated after the correction date. 2) To patch your present system: The following patches have been verified to apply to FreeBSD 4.10, 4.11, 5.3, 5.4, and 6.0 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-06:11/ipsec.patch # fetch ftp://ftp.FreeBSD.org/pub/FreeBSD/CERT/patches/SA-06:11/ipsec.patch.asc b) Apply the patch. # 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 revision numbers of each file that was corrected in FreeBSD. Branch Revision Path - - ------------------------------------------------------------------------- RELENG_4 src/sys/netipsec/xform_esp.c 1.2.2.4 RELENG_4_11 src/UPDATING 1.73.2.91.2.17 src/sys/conf/newvers.sh 1.44.2.39.2.20 src/sys/netipsec/xform_esp.c 1.2.2.3.6.1 RELENG_4_10 src/UPDATING 1.73.2.90.2.23 src/sys/conf/newvers.sh 1.33.2.34.2.24 src/sys/netipsec/xform_esp.c 1.2.2.3.4.1 RELENG_5 src/sys/netipsec/xform_esp.c 1.9.2.2 RELENG_5_4 src/UPDATING 1.342.2.24.2.22 src/sys/conf/newvers.sh 1.62.2.18.2.18 src/sys/netipsec/xform_esp.c 1.9.2.1.2.1 RELENG_5_3 src/UPDATING 1.342.2.13.2.31 src/sys/conf/newvers.sh 1.62.2.15.2.33 src/sys/netipsec/xform_esp.c 1.9.4.1 RELENG_6 src/sys/netipsec/xform_esp.c 1.10.2.1 RELENG_6_0 src/UPDATING 1.416.2.3.2.11 src/sys/conf/newvers.sh 1.69.2.8.2.7 src/sys/netipsec/xform_esp.c 1.10.4.1 - - ------------------------------------------------------------------------- VII. References http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2006-0905 The latest revision of this advisory is available at ftp://ftp.freebsd.org/pub/FreeBSD/CERT/advisories/FreeBSD-SA-06:11.ipsec.asc - -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.2.2 (FreeBSD) iD8DBQFEIXZEFdaIBMps37IRAuqlAJ9ri+xFH1TGs96vNt788uo6plbu1ACcDau4 dm/4Df3zy7GguI+Ekp/hHuQ= =+iZv - -----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 iQCVAwUBRCHdnyh9+71yA2DNAQI96QP/ZxFWFFXNBY4AA40D6LmDAGtvDmt4vCRf 0cZSVcUqvXaD3yRURJulqXgFpfjvujj5thgYVxelfN8owv5UaYZRLgnZVs2Vuh2l tolG2yw6pzYDkyzTIn79gK7J62NRsP/KMLiiSBpMmjTOLGyrVTUtHBvraN8nXiT6 vGKRhB5EOF0= =jMde -----END PGP SIGNATURE-----