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Posted on 06 September 2023
FreeBSD security notificat=============================================================================FreeBSD-SA-23:11.wifi Security Advisory
The FreeBSD Project
Topic: Wi-Fi encryption bypass
Category: core
Module: net80211
Announced: 2023-09-06
Credits: See the paper linked in the References section.
Affects: All supported versions of FreeBSD.
Corrected: 2023-06-26 12:02:00 UTC (stable/13, 13.2-STABLE)
2023-09-06 17:13:25 UTC (releng/13.2, 13.2-RELEASE-p3)
2023-06-26 12:30:23 UTC (stable/12, 12.4-STABLE)
2023-09-06 17:38:34 UTC (releng/12.4, 12.4-RELEASE-p5)
CVE Name: CVE-2022-47522
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
FreeBSD's net80211 kernel subsystem provides infrastructure and drivers
for IEEE 802.11 wireless (Wi-Fi) communications. Wi-Fi communications rely
on both unicast and multicast keys to secure transmissions.
II. Problem Description
The net80211 subsystem would fallback to the multicast key for unicast
traffic in the event the unicast key was removed. This would result in
buffered unicast traffic being exposed to any stations with access to the
multicast key.
III. Impact
As described in the "Framing Frames: Bypassing Wi-Fi Encryption by
Manipulating Transmit Queues" paper, an attacker can induce an access point
to buffer frames for a client, deauthenticate the client (causing the unicast
key to be removed from the access point), and subsequent flushing of the
buffered frames now encrypted with the multicast key. This would give the
attacker access to the data.
IV. Workaround
No workaround is available. Systems not using Wi-Fi are not affected.
V. Solution
Upgrade your vulnerable system to a supported FreeBSD stable or
release / security branch (releng) dated after the correction date
and reboot
Perform one of the following:
1) To update your vulnerable system via a binary patch:
Systems running a RELEASE version of FreeBSD on the amd64, i386, or
(on FreeBSD 13 and later) arm64 platforms can be updated via the
freebsd-update(8) utility:
# freebsd-update fetch
# freebsd-update install
# shutdown -r +10min "Rebooting for a security update"
2) 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-23:11/wifi.patch
# fetch https://security.FreeBSD.org/patches/SA-23:11/wifi.patch.asc
# gpg --verify wifi.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
This issue is corrected by the corresponding Git commit hash or Subversion
revision number in the following stable and release branches:
Branch/path Hash Revision
- -------------------------------------------------------------------------
stable/13/ 6c9bcecfb296 stable/13-n255680
releng/13.2/ 7f34ee7cc56b releng/13.2-n254632
stable/12/ r373115
releng/12.4/ r373187
- -------------------------------------------------------------------------
For FreeBSD 13 and later:
Run the following command to see which files were modified by a
particular commit:
# git show --stat <commit hash>
Or visit the following URL, replacing NNNNNN with the hash:
<URL:https://cgit.freebsd.org/src/commit/?id=NNNNNN>
To determine the commit count in a working tree (for comparison against
nNNNNNN in the table above), run:
# git rev-list --count --first-parent HEAD
For FreeBSD 12 and earlier:
Run the following command to see which files were modified by a particular
revision, replacing NNNNNN with the revision number:
# 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://papers.mathyvanhoef.com/usenix2023-wifi.pdf>
<URL:https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2022-47522>
The latest revision of this advisory is available at
<URL:https://security.FreeBSD.org/advisories/FreeBSD-SA-23:11.wifi.asc>
