what you don't know can hurt you
Home Files News &[SERVICES_TAB]About Contact Add New

FreeBSD Security Advisory - FreeBSD-SA-19:05.pf

FreeBSD Security Advisory - FreeBSD-SA-19:05.pf
Posted May 15, 2019
Authored by Synacktiv | Site security.freebsd.org

FreeBSD Security Advisory - A bug in the pf(4) IPv6 fragment reassembly logic incorrectly uses the last extension header offset from the last received packet instead of from the first packet. Malicious IPv6 packets with different IPv6 extensions could cause a kernel panic or potentially a filtering rule bypass.

tags | advisory, kernel
systems | freebsd
advisories | CVE-2019-5597
SHA-256 | 97bbcb3ce672debfe19dd8c848fe63f318427adee581b312031e315e30650a3a

FreeBSD Security Advisory - FreeBSD-SA-19:05.pf

Change Mirror Download
-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA512

=============================================================================
FreeBSD-SA-19:05.pf Security Advisory
The FreeBSD Project

Topic: IPv6 fragment reassembly panic in pf(4)

Category: contrib
Module: pf
Announced: 2019-05-14
Credits: Synacktiv
Affects: All supported versions of FreeBSD
Corrected: 2019-03-01 18:12:05 UTC (stable/12, 12.0-STABLE)
2019-05-14 23:10:21 UTC (releng/12.0, 12.0-RELEASE-p4)
2019-03-01 18:12:07 UTC (stable/11, 11.3-PRERELEASE)
2019-05-14 23:10:21 UTC (releng/11.2, 11.2-RELEASE-p10)
CVE Name: CVE-2019-5597

For general information regarding FreeBSD Security Advisories,
including descriptions of the fields above, security branches, and the
following sections, please visit <URL:https://security.FreeBSD.org/>.

I. Background

pf(4) is an Internet Protocol packet filter originally written for OpenBSD.
In addition to filtering packets, it also has packet normalization
capabilities.

II. Problem Description

A bug in the pf(4) IPv6 fragment reassembly logic incorrectly uses the last
extension header offset from the last received packet instead of from the
first packet.

III. Impact

Malicious IPv6 packets with different IPv6 extensions could cause a kernel
panic or potentially a filtering rule bypass.

IV. Workaround

Only systems leveraging the pf(4) firewall and include packet scrubbing using
the recommended 'scrub all in' or similar are affected.

V. Solution

Perform one of the following:

1) Upgrade your vulnerable system to a supported FreeBSD stable or
release / security branch (releng) dated after the correction date.
Afterwards, reboot the system.

2) To update your vulnerable system via a binary patch:

Systems running a RELEASE version of FreeBSD on the i386 or amd64
platforms can be updated via the freebsd-update(8) utility:

# freebsd-update fetch
# freebsd-update install

Afterwards, reboot the system.

3) To update your vulnerable system via a source code patch:

The following patches have been verified to apply to the applicable
FreeBSD release branches.

a) Download the relevant patch from the location below, and verify the
detached PGP signature using your PGP utility.

# fetch https://security.FreeBSD.org/patches/SA-19:05/pf.patch
# fetch https://security.FreeBSD.org/patches/SA-19:05/pf.patch.asc
# gpg --verify pf.patch.asc

b) Apply the patch. Execute the following commands as root:

# cd /usr/src
# patch < /path/to/patch

c) Recompile your kernel as described in
<URL:https://www.FreeBSD.org/handbook/kernelconfig.html> and reboot the
system.

VI. Correction details

The following list contains the correction revision numbers for each
affected branch.

Branch/path Revision
- -------------------------------------------------------------------------
stable/12/ r344706
releng/12.0/ r347591
stable/11/ r344707
releng/11.2/ r347591
- -------------------------------------------------------------------------

To see which files were modified by a particular revision, run the
following command, replacing NNNNNN with the revision number, on a
machine with Subversion installed:

# svn diff -cNNNNNN --summarize svn://svn.freebsd.org/base

Or visit the following URL, replacing NNNNNN with the revision number:

<URL:https://svnweb.freebsd.org/base?view=revision&revision=NNNNNN>

VII. References

<URL:https://www.synacktiv.com/ressources/Synacktiv_OpenBSD_PacketFilter_CVE-2019-5597_ipv6_frag.pdf>

<URL:https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2019-5597>

The latest revision of this advisory is available at
<URL:https://security.FreeBSD.org/advisories/FreeBSD-SA-19:05.pf.asc>
-----BEGIN PGP SIGNATURE-----
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=0alQ
-----END PGP SIGNATURE-----
Login or Register to add favorites

File Archive:

September 2022

  • Su
  • Mo
  • Tu
  • We
  • Th
  • Fr
  • Sa
  • 1
    Sep 1st
    23 Files
  • 2
    Sep 2nd
    12 Files
  • 3
    Sep 3rd
    0 Files
  • 4
    Sep 4th
    0 Files
  • 5
    Sep 5th
    10 Files
  • 6
    Sep 6th
    8 Files
  • 7
    Sep 7th
    30 Files
  • 8
    Sep 8th
    14 Files
  • 9
    Sep 9th
    26 Files
  • 10
    Sep 10th
    0 Files
  • 11
    Sep 11th
    0 Files
  • 12
    Sep 12th
    5 Files
  • 13
    Sep 13th
    28 Files
  • 14
    Sep 14th
    15 Files
  • 15
    Sep 15th
    17 Files
  • 16
    Sep 16th
    9 Files
  • 17
    Sep 17th
    0 Files
  • 18
    Sep 18th
    0 Files
  • 19
    Sep 19th
    12 Files
  • 20
    Sep 20th
    15 Files
  • 21
    Sep 21st
    20 Files
  • 22
    Sep 22nd
    13 Files
  • 23
    Sep 23rd
    12 Files
  • 24
    Sep 24th
    0 Files
  • 25
    Sep 25th
    0 Files
  • 26
    Sep 26th
    30 Files
  • 27
    Sep 27th
    27 Files
  • 28
    Sep 28th
    8 Files
  • 29
    Sep 29th
    14 Files
  • 30
    Sep 30th
    19 Files

Top Authors In Last 30 Days

File Tags

Systems

packet storm

© 2022 Packet Storm. All rights reserved.

Hosting By
Rokasec
close