TUCoPS :: BSD :: ciacj067.txt

FreeBSD Profiling Across FreeBSD Exec Calls



                       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
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

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 @@
                p->p_fd = tmp;
    +   /* Stop profiling */
    +   stopprofclock(p);

        /* close files on exec */

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.

CIAC services are available to DOE, DOE contractors, and the NIH. CIAC
can be contacted at:
    Voice:    +1 925-422-8193
    FAX:      +1 925-423-8002
    STU-III:  +1 925-423-2604
    E-mail:   ciac@llnl.gov

For emergencies and off-hour assistance, DOE, DOE contractor sites,
and the NIH may contact CIAC 24-hours a day. During off hours (5PM -
8AM PST), use one of the following methods to contact CIAC:

    1.  Call the CIAC voice number 925-422-8193 and leave a message, or

    2.  Call 888-449-8369 to send a Sky Page to the CIAC duty person or

    3.  Send e-mail to 4498369@skytel.com, or

    4.  Call 800-201-9288 for the CIAC Project Leader.

Previous CIAC notices, anti-virus software, and other information are
available from the CIAC Computer Security Archive.

   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
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
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. To
subscribe (add yourself) to one of our mailing lists, send the
following request as the E-mail message body, substituting
ciac-bulletin, spi-announce OR spi-notes for list-name:

E-mail to       ciac-listproc@llnl.gov or majordomo@rumpole.llnl.gov:
        subscribe list-name
  e.g., subscribe ciac-bulletin

You will receive an acknowledgment email immediately with a confirmation
that you will need to mail back to the addresses above, as per the
instructions in the email.  This is a partial protection to make sure
you are really the one who asked to be signed up for the list in question.

If you include the word 'help' in the body of an email to the above address,
it will also send back an information file on how to subscribe/unsubscribe,
get past issues of CIAC bulletins via email, etc.

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. The views and opinions of authors expressed
herein do not necessarily state or reflect those of the United States
Government or the University of California, and shall not be used for
advertising or product endorsement purposes.

LAST 10 CIAC BULLETINS ISSUED (Previous bulletins available from CIAC)

J-057: Windows NT(r) Terminal Servers DOS Vulnerability
J-058: Microsoft "Malformed HTTP Request Header" Vulnerability
J-059: IBM AIX (pdnsd) Buffer Overflow Vulnerability
J-060: Microsoft Office "ODBC" Vulnerabilities
J-061: Lotus Notes Domino Server Denial of Service Attacks
J-062: Netscape Enterprise and FastTrack Web Servers Buffer Overflow
J-063: Domain Name System (DNS) Denial of Service (DoS) Attacks
J-064: ActiveX Controls, Scriptlet.typlib & Eyedog, Vulnerabilities
J-065: Wu-ftpd Vulnerability
J-066: FreeBSD File Flags and Man-In-The-Middle Attack

Version: 4.0 Business Edition


TUCoPS is optimized to look best in Firefox® on a widescreen monitor (1440x900 or better).
Site design & layout copyright © 1986-2024 AOH