-----BEGIN PGP SIGNED MESSAGE----- __________________________________________________________ The U.S. Department of Energy Computer Incident Advisory Capability ___ __ __ _ ___ / | /_\ / \___ __|__ / \ \___ __________________________________________________________ INFORMATION BULLETIN Profiling Across FreeBSD Exec Calls September 8, 1999 17:00 GMT Number J-067 _____________________________________________________________________________ PROBLEM: FreeBSD's profiling mechanism allows an attacker to start execution at any arbitrary location in the program being profiled. PLATFORM: All systems running FreeBSD 3.2 (and earlier) or FreeBSD-Current before August 11, 1999. DAMAGE: An attacker could theoretically gain root access from a carefully crafted attack. SOLUTION: Apply the available patches. There are no immediate or temporary workarounds. _____________________________________________________________________________ VULNERABILITY The risk is MEDIUM. It is possible to gain root access but ASSESSMENT: there are no known attacks at this time. _____________________________________________________________________________ [ Start FreeBSD Advisory ] ============================================================================= FreeBSD-SA-99:02 Security Advisory FreeBSD, Inc. Topic: Profiling Across Exec Calls Category: core Module: kernel Announced: 1999-09-04 Affects: FreeBSD 3.2 (and earlier) FreeBSD-current before the correction date. Corrected: FreeBSD-3.3 RELEASE FreeBSD-current as of August 11, 1999 FreeBSD-3.2-stable as of August 22, 1999 FreeBSD only: No Patches: ftp://ftp.freebsd.org/pub/FreeBSD/CERT/patches/SA-99:02/ I. Background FreeBSD provides a mechanism to profile a running executable to aid in performance tuning. This can be accomplished via a kernel mechanism to statistically sample the program counter of the program under profile. II. Problem Description A flaw exists in the implementation which allows an attacker to cause arbitrary locations in program executed by the attacker. III. Impact No attacks against using this vulnerability this are known at this time. An attacker could theoretically gain root access from a carefully crafted attack. IV. Workaround Since profiling is done in the kernel via the profil(2) system call, one must patch the kernel so no workaround is possible. V. Solution Apply the following patch. It will apply to both FreeBSD-current before the resolution date and to 3.2-stable before the resolution date. Index: kern_exec.c =================================================================== RCS file: /home/imp/FreeBSD/CVS/src/sys/kern/kern_exec.c,v retrieving revision 1.99 retrieving revision 1.100 diff -u -r1.99 -r1.100 --- kern_exec.c 1999/04/27 11:15:55 1.99 +++ kern_exec.c 1999/08/11 20:35:38 1.100 @@ -228,6 +228,9 @@ fdfree(p); p->p_fd = tmp; } + + /* Stop profiling */ + stopprofclock(p); /* close files on exec */ fdcloseexec(p); ============================================================================= FreeBSD, Inc. Web Site: http://www.freebsd.org/ Confidential contacts: security-officer@freebsd.org Security notifications: security-notifications@freebsd.org Security public discussion: freebsd-security@freebsd.org PGP Key: ftp://ftp.freebsd.org/pub/FreeBSD/CERT/public_key.asc Notice: Any patches in this document may not apply cleanly due to modifications caused by digital signature or mailer software. Please reference the URL listed at the top of this document for original copies of all patches if necessary. ============================================================================= [ End FreeBSD Advisory ] _____________________________________________________________________________ CIAC wishes to acknowledge the contributions of FreeBSD, Inc. 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. 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World Wide Web: http://www.ciac.org/ (or http://ciac.llnl.gov -- they're the same machine) Anonymous FTP: ftp.ciac.org (or ciac.llnl.gov -- they're the same machine) Modem access: +1 (925) 423-4753 (28.8K baud) +1 (925) 423-3331 (28.8K baud) CIAC has several self-subscribing mailing lists for electronic publications: 1. CIAC-BULLETIN for Advisories, highest priority - time critical information and Bulletins, important computer security information; 2. SPI-ANNOUNCE for official news about Security Profile Inspector (SPI) software updates, new features, distribution and availability; 3. SPI-NOTES, for discussion of problems and solutions regarding the use of SPI products. Our mailing lists are managed by a public domain software package called Majordomo, which ignores E-mail header subject lines. 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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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