—–BEGIN PGP SIGNED MESSAGE—–
Hash: SHA512

=============================================================================
FreeBSD-SA-19:06.pf Security Advisory
The FreeBSD Project

Topic: ICMP/ICMP6 packet filter bypass in pf

Category: contrib
Module: pf
Announced: 2019-05-14
Credits: Synacktiv
Affects: All supported versions of FreeBSD
Corrected: 2019-03-21 14:17:10 UTC (stable/12, 12.0-STABLE)
2019-05-14 23:12:22 UTC (releng/12.0, 12.0-RELEASE-p4)
2019-03-21 14:17:12 UTC (stable/11, 11.3-PRERELEASE)
2019-05-14 23:12:22 UTC (releng/11.2, 11.2-RELEASE-p10)
CVE Name: CVE-2019-5598

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

States in pf(4) let ICMP and ICMP6 packets pass if they have a packet in
their payload matching an existing condition. pf(4) does not check if the
outer ICMP or ICMP6 packet has the same destination IP as the source IP of
the inner protocol packet.

III. Impact

A maliciously crafted ICMP/ICMP6 packet could bypass the packet filter rules
and be passed to a host that would otherwise be unavailable.

IV. Workaround

No workaround is available.

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-19:06/pf.patch
# fetch https://security.FreeBSD.org/patches/SA-19:06/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/ r345377
releng/12.0/ r347593
stable/11/ r345378
releng/11.2/ r347593
– ————————————————————————-

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/posts/systems/icmp-reachable.html>

<URL:https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2019-5598>

The latest revision of this advisory is available at
<URL:https://security.FreeBSD.org/advisories/FreeBSD-SA-19:06.pf.asc>
—–BEGIN PGP SIGNATURE—–
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=m3as
—–END PGP SIGNATURE—–
_______________________________________________
freebsd-security-notifications@freebsd.org mailing list
https://lists.freebsd.org/mailman/listinfo/freebsd-security-notifications
To unsubscribe, send any mail to “freebsd-security-notifications-unsubscribe@freebsd.org”