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Home » Security Advisories» FreeBSD » FreeBSD-SA-02:29-Buffer overflow in tcpdump when handling NFS packets

FreeBSD-SA-02:29-Buffer overflow in tcpdump when handling NFS packets

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.

  • Vendor: FreeBSD
  • Vendor ID: SA-02:29
  • Date: July 14, 2002


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

-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.0.7 (FreeBSD)

iQCVAwUBPS8+yFUuHi5z0oilAQGEaAQApQpuobpvrYILjiJh9Zvfnupop9aDuQ/G
9RvnGVv0ZXrKtD8aRiP3JrjouGvZm9WLqXsXlnf0wmTXdWWg5ibjuJK/gDtdiqjA
iuZvq5Rx+IKD33pZpAocg74zIv3nDYv1S+3ndJXtYcSFw7EnC4QHu3mFrZK81RcQ
6LpcUuxVTl8=
=hQ/2
-----END PGP SIGNATURE-----

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