FreeBSD Security Advisory FreeBSD-SA-02:29.tcpdump

From: FreeBSD Security Advisories (security-advisoriesat_private)
Date: Fri Jul 12 2002 - 13:46:02 PDT

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    FreeBSD-SA-02:29                                            Security Advisory
                                                              The FreeBSD Project
    
    Topic:          Buffer overflow in tcpdump when handling NFS packets
    
    Category:       contrib
    Module:         tcpdump
    Announced:      2002-07-12
    Credits:        dwmw2at_private
    Affects:        All releases prior to and including 4.6-RELEASE
                    FreeBSD 4.6-STABLE prior to the correction date
    Corrected:      2002-07-05 13:24:57 UTC (RELENG_4)
                    2002-07-12 13:29:47 UTC (RELENG_4_6)
                    2002-07-12 13:31:10 UTC (RELENG_4_5)
                    2002-07-12 13:31:44 UTC (RELENG_4_4)
    FreeBSD only:   NO
    
    I.   Background
    
    The tcpdump utility is used to capture and examining network traffic.
    
    II.  Problem Description
    
    Versions of tcpdump up to and including 3.7.1 contain a buffer
    overflow that may be triggered by badly formed NFS packets, and
    possibly other types of packets.
    
    III. Impact
    
    It is not currently known whether this buffer overflow is exploitable.
    If it were, an attacker could inject specially crafted packets into
    the network which, when processed by tcpdump, could lead to arbitrary
    code execution with the privileges of the user running tcpdump
    (typically `root').
    
    IV.  Workaround
    
    There is no workaround, other than not using tcpdump.
    
    V.   Solution
    
    Do one of the following:
    
    1) Upgrade your vulnerable system to 4.6-STABLE; or to the RELENG_4_6,
    RELENG_4_5, or RELENG_4_4 security branch dated after the correction
    date (4.6-RELEASE-p2, 4.5-RELEASE-p8, or 4.4-RELEASE-p15).
    
    2) To patch your present system:
    
    The following patch has been verified to apply to FreeBSD 4.4, 4.5, and
    4.6 systems.
    
    a) Download the relevant patch from the location below, and verify the
    detached PGP signature using your PGP utility.
    
    # fetch ftp://ftp.FreeBSD.org/pub/FreeBSD/CERT/patches/SA-02:29/tcpdump.patch
    # fetch ftp://ftp.FreeBSD.org/pub/FreeBSD/CERT/patches/SA-02:29/tcpdump.patch.asc
    
    b) Execute the following commands as root:
    
    # cd /usr/src
    # patch < /path/to/patch
    # cd /usr/src/usr.sbin/tcpdump
    # make depend && make && make install
    
    VI.  Correction details
    
    The following list contains the revision numbers of each file that was
    corrected in FreeBSD.
    
    Path                                                             Revision
      Branch
    - -------------------------------------------------------------------------
    src/contrib/tcpdump/interface.h
      RELENG_4                                                        1.4.2.3
      RELENG_4_6                                                  1.4.2.1.6.1
      RELENG_4_5                                                  1.4.2.1.4.1
      RELENG_4_4                                                  1.4.2.1.2.1
    - -------------------------------------------------------------------------
    
    VII. References
    
    <URL:http://rhn.redhat.com/errata/RHSA-2002-094.html>
    <URL:http://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=55145>
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