11 October 2006
Protect yourself against future threats.
-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 =========================================================================== AUSCERT External Security Bulletin Redistribution ESB-2006.0750 -- [FreeBSD] FreeBSD ptrace PT_LWPINFO Denial of Service Vulnerability 11 October 2006 =========================================================================== AusCERT Security Bulletin Summary --------------------------------- Product: ptrace Publisher: iDEFENSE Operating System: FreeBSD Impact: Denial of Service Access: Existing Account CVE Names: CVE-2006-4516 - --------------------------BEGIN INCLUDED TEXT-------------------- FreeBSD ptrace PT_LWPINFO Denial of Service Vulnerability iDefense Security Advisory 10.10.06 http://www.idefense.com/intelligence/vulnerabilities/ Oct 10, 2006 I. BACKGROUND FreeBSD is a modern operating system for x86, amd64, Alpha, IA-64, PC-98 and SPARC architectures. It's based on the UNIX operating system, BSD, which was created at the University of California, Berkeley. More information can be obtained from the FreeBSD Project web site at http://www.FreeBSD.org/ II. DESCRIPTION The PT_LWPINFO ptrace command allows a tracer to get information on a running thread. Due to the use of signed integers and a lack of proper input validation, a situation can occur in the kernel where a panic will cause DoS. The affected code follows. 953 case PT_LWPINFO: 954 if (data == 0 || data > sizeof(*pl)) 955 return (EINVAL); Since the "data" variable is a signed integer, the check on line 954 can easily be bypassed. Eventually, the negative value is passed to copyout(), which will result in a kernel panic or corruption of the user space memory. III. ANALYSIS Exploitation of this vulnerability would result in a denial of service condition on the affected host. In some cases exploitation resulted in a hard lock up of the machine, where as other times a kernel panic was caused leading to reboot. iDefense considers this a LOW severity vulnerability due to the local access requirement. IV. DETECTION iDefense has confirmed the existence of this problem in FreeBSD version 6.0-RELEASE. FreeBSD 6.1-RELEASE is not affected. It is suspected that other versions are also affected. V. WORKAROUND iDefense is not aware of any workaround for this issue. VI. VENDOR RESPONSE "The policy of the FreeBSD Security Team is that local denial of service bugs not be treated as security issues; it is possible that this problem will be corrected in a future Erratum." VII. CVE INFORMATION The Common Vulnerabilities and Exposures (CVE) project has assigned the name CVE-2006-4516 to this issue. This is a candidate for inclusion in the CVE list (http://cve.mitre.org), which standardizes names for security problems. VIII. DISCLOSURE TIMELINE 08/18/2006 Initial vendor notification 10/06/2006 Initial vendor response 10/10/2006 Public disclosure IX. CREDIT The discoverer of this vulnerability wishes to remain anonymous. Get paid for vulnerability research http://www.idefense.com/methodology/vulnerability/vcp.php Free tools, research and upcoming events http://labs.idefense.com/ X. LEGAL NOTICES Copyright Â© 2006 iDefense, Inc. Permission is granted for the redistribution of this alert electronically. It may not be edited in any way without the express written consent of iDefense. If you wish to reprint the whole or any part of this alert in any other medium other than electronically, please email email@example.com for permission. Disclaimer: The information in the advisory is believed to be accurate at the time of publishing based on currently available information. Use of the information constitutes acceptance for use in an AS IS condition. There are no warranties with regard to this information. Neither the author nor the publisher accepts any liability for any direct, indirect, or consequential loss or damage arising from use of, or reliance on, this information. - --------------------------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 firstname.lastname@example.org 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: email@example.com 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 iQCVAwUBRSx26Sh9+71yA2DNAQLtHAQAhaSgyeklEPT+3THOze5GtJaDryZ0ZrEJ Gha7lOuzZJR/CngTfrXxl5kLz8s76U30tqYGnVrCf1y1ETDVi0OlfHr0ENo8ND0G okb0srD3g7ccZ2OfR0m2g9hW+zBfMC0Bboj+GL2xtFb93SPin70oIJjiRbxdo5dI p8qXEUrF+lw= =HL+d -----END PGP SIGNATURE-----