From owner-freebsd-questions@FreeBSD.ORG Tue Oct 10 22:51:46 2006 Return-Path: X-Original-To: questions@freebsd.org Delivered-To: freebsd-questions@FreeBSD.ORG Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id C37DA16A40F for ; Tue, 10 Oct 2006 22:51:46 +0000 (UTC) (envelope-from wmoran@collaborativefusion.com) Received: from mx00.pub.collaborativefusion.com (mx00.pub.collaborativefusion.com [206.210.89.199]) by mx1.FreeBSD.org (Postfix) with ESMTP id 0502643D73 for ; Tue, 10 Oct 2006 22:51:43 +0000 (GMT) (envelope-from wmoran@collaborativefusion.com) Received: from localhost (c-71-60-174-60.hsd1.pa.comcast.net [71.60.174.60]) (AUTH: LOGIN wmoran, TLS: TLSv1/SSLv3,256bits,AES256-SHA) by wingspan with esmtp; Tue, 10 Oct 2006 18:51:42 -0400 id 00056414.452C23FE.00001509 Date: Tue, 10 Oct 2006 18:51:41 -0400 From: Bill Moran To: questions@freebsd.org Message-Id: <20061010185141.ce3e7134.wmoran@collaborativefusion.com> Organization: Collaborative Fusion X-Mailer: Sylpheed version 2.2.7 (GTK+ 2.8.20; i386-portbld-freebsd6.1) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Cc: Subject: iDefense Security Advisory 10.10.06: FreeBSD ptrace PT_LWPINFO Denial of Service Vulnerability X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 10 Oct 2006 22:51:46 -0000 This report seems pretty vague. I'm unsure as to whether the alleged "bug" gives the user any more permissions than he'd already have? Anyone know any details? 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 -- Bill Moran Sometimes I think I'm stupid. The rest of the time I'm sure of it.