__________________________________________________________ The U.S. Department of Energy Computer Incident Advisory Capability ___ __ __ _ ___ / | /_\ / \___ __|__ / \ \___ __________________________________________________________ INFORMATION BULLETIN Linux Kernel Vulnerable to DoS via ipv6_getsockopt_sticky() Function [US-CERT Vulnerability Note VU#920689] March 14, 2007 19:00 GMT Number R-177 [REVISED 1 May 2007] ______________________________________________________________________________ PROBLEM: The Linux Kernel contains a vulnerability that may allow a remote attacker to create a denial-of-service condition. PLATFORM: Linux Kernel version 2.6.20.1 RHEL Desktop Workstation (v. 5 client) Red Hat Enterprise Linux (v. 5 server) Red Hat Enterprise Linux Desktop (v. 5 client) DAMAGE: May allow a remote attacker to create a denial-of-service condition. SOLUTION: Upgrade to the appropriate version. ______________________________________________________________________________ VULNERABILITY The risk is LOW. May allow a remote attacker to create a ASSESSMENT: denial-of-service condition. ______________________________________________________________________________ LINKS: CIAC BULLETIN: http://www.ciac.org/ciac/bulletins/r-177.shtml ORIGINAL BULLETIN: http://www.kb.cert.org/vuls/id/920689 ADDITIONAL LINK: https://rhn.redhat.com/errata/RHSA-2007-0169.html CVE: http://www.cve.mitre.org/cgi-bin/cvename.cgi?name= CVE-2007-1000 ______________________________________________________________________________ REVISION HISTORY: 05/01/2007 - revised R-177 to add a link to Red Hat RHSA-2007:0169-2 for RHEL Desktop Workstation (v. 5 client), Red Hat Enterprise Linux (v. 5 server), and Red Hat Enterprise Linux Desktop (v. 5 client). [***** Start US-CERT Vulnerability Note VU#920689 *****] Vulnerability Note VU#920689 Linux Kernel vulnerable to DoS via the ipv6_getsockopt_sticky() function Overview The Linux Kernel contains a vulnerability that may allow a remote attacker to create a denial-of-service condition. I. Description Internet Protocol version 6 (IPv6) is a IP standard that is designed to replace the Internet Protocol version 4 (IPv4). The Linux kernel provides IPv6 support, and Linux vendors may enable IPv6 by default. The Linux kernel contains a condition that may allow a null pointer to be dereferenced during a memory allocation by the ipv6_getsockopt_sticky() function in net/ipv6/ipv6_sockglue.c. Note that this vulnerability may be present in both the 2.4 and 2.6 versions of the Linux kernel. II. Impact A remote unauthenticated attacker may be able to cause the kernel to panic (Oops) on a vulnerable system, thereby creating a denial of service.. If the vulnerable software is running on a server, all clients that rely on the server will also be affected. III. Solution Upgrade This issue has been addressed in Linux kernel version 2.6.20.2. Users who do not compile their kernels from source should contact their operating system vendor for updated kernel packages. Disable IPv6 If IPv6 functionality is not needed, disabling it may mitigate this vulnerability. Adding alias net-pf-10 ipv6 off to your modprobe configuration file and rebooting may disable IPv6 functionality. Systems Affected Vendor Status Date Updated Linux Kernel Archives Vulnerable 13-Mar-2007 References http://bugzilla.kernel.org/show_bug.cgi?id=8134 http://kernel.org/pub/linux/kernel/v2.6/ChangeLog-2.6.20.2 https://www.securecoding.cert.org/confluence/display/seccode/Do+not+dereference+ invalid+pointers http://www.kernel.org/ http://secunia.com/advisories/24493/ http://en.wikipedia.org/wiki/Ipv6 http://en.wikipedia.org/wiki/Ipv4 Credit Thanks to Chris Wright for information that was used in this report. This document was written by Ryan Giobbi. Other Information Date Public 03/12/2007 Date First Published 03/13/2007 01:54:21 PM Date Last Updated 03/13/2007 CERT Advisory CVE Name CVE-2007-1000 Metric 3.71 Document Revision 13 [***** End US-CERT Vulnerability Note VU#920689 *****] _______________________________________________________________________________ CIAC wishes to acknowledge the contributions of US-CERT for the information contained in this bulletin. _______________________________________________________________________________ CIAC, the Computer Incident Advisory Capability, is the computer security incident response team for the U.S. Department of Energy (DOE) and the emergency backup response team for the National Institutes of Health (NIH). CIAC is located at the Lawrence Livermore National Laboratory in Livermore, California. CIAC is also a founding member of FIRST, the Forum of Incident Response and Security Teams, a global organization established to foster cooperation and coordination among computer security teams worldwide. CIAC services are available to DOE, DOE contractors, and the NIH. CIAC can be contacted at: Voice: +1 925-422-8193 (7x24) FAX: +1 925-423-8002 STU-III: +1 925-423-2604 E-mail: ciac@ciac.org Previous CIAC notices, anti-virus software, and other information are available from the CIAC Computer Security Archive. World Wide Web: http://www.ciac.org/ Anonymous FTP: ftp.ciac.org PLEASE NOTE: Many users outside of the DOE, ESnet, and NIH computing communities receive CIAC bulletins. If you are not part of these communities, please contact your agency's response team to report incidents. Your agency's team will coordinate with CIAC. The Forum of Incident Response and Security Teams (FIRST) is a world-wide organization. A list of FIRST member organizations and their constituencies can be obtained via WWW at http://www.first.org/. This document was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor the University of California nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial products, process, or service by trade name, trademark, manufacturer, or otherwise, does not necessarily constitute or imply its endorsement, recommendation or favoring by the United States Government or the University of California. 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