EAP-pwd side-channel attack
Published: April 10, 2019
Identifiers:
- CVE-2019-9495 (cache attack against EAP-pwd)
Latest version available from: https://w1.fi/security/2019-2/
Vulnerability
Number of potential side channel attacks were recently discovered in the
SAE implementations used by both hostapd and wpa_supplicant (see
security advisory 2019-1 and VU#871675). EAP-pwd uses a similar design
for deriving PWE from the password and while a specific attack against
EAP-pwd is not yet known to be tested, there is no reason to believe
that the EAP-pwd implementation would be immune against the type of
cache attack that was identified for the SAE implementation. Since the
EAP-pwd implementation in hostapd (EAP server) and wpa_supplicant (EAP
peer) does not support MODP groups, the timing attack described against
SAE is not applicable for the EAP-pwd implementation.
A novel cache-based attack against SAE handshake would likely be
applicable against the EAP-pwd implementation. Even though the
wpa_supplicant/hostapd PWE derivation iteration for EAP-pwd has
protections against timing attacks, this new cache-based attack might
enable an attacker to determine which code branch is taken in the
iteration if the attacker is able to run unprivileged code on the victim
machine (e.g., an app installed on a smart phone or potentially a
JavaScript code on a web site loaded by a web browser). This depends on
the used CPU not providing sufficient protection to prevent unprivileged
applications from observing memory access patterns through the shared
cache (which is the most likely case with today's designs).
The attacker could use information about the selected branch to learn
information about the password and combine this information from number
of handshake instances with an offline dictionary attack. With
sufficient number of handshakes and sufficiently weak password, this
might result in full recovery of the used password if that password is
not strong enough to protect against dictionary attacks.
This attack requires the attacker to be able to run a program on the
target device. This is not commonly the case on an authentication server
(EAP server), so the most likely target for this would be a client
device using EAP-pwd.
The commits listed in the end of this advisory change the EAP-pwd
implementation shared by hostapd and wpa_supplicant to perform the PWE
derivation loop using operations that use constant time and memory
access pattern to minimize the externally observable differences from
operations that depend on the password even for the case where the
attacker might be able to run unprivileged code on the same device.
Vulnerable versions/configurations
All wpa_supplicant and hostapd versions with EAP-pwd support
(CONFIG_EAP_PWD=y in the build configuration and EAP-pwd being enabled
in the runtime configuration).
It should also be noted that older versions of wpa_supplicant/hostapd
prior to v2.7 did not include additional protection against certain
timing differences. The definition of the EAP-pwd (RFC 5931) does not
describe such protection, but the same issue that was addressed in SAE
earlier can be applicable against EAP-pwd as well and as such, that
implementation specific extra protection (commit 22ac3dfebf7b, "EAP-pwd:
Mask timing of PWE derivation") is needed to avoid showing externally
visible timing differences that could leak information about the
password. Any uses of older wpa_supplicant/hostapd versions with EAP-pwd
are recommended to update to v2.7 or newer in addition to the mitigation
steps listed below for the more recently discovered issue.
Possible mitigation steps
- Merge the following commits to wpa_supplicant/hostapd and rebuild:
OpenSSL: Use constant time operations for private bignums
Add helper functions for constant time operations
OpenSSL: Use constant time selection for crypto_bignum_legendre()
EAP-pwd: Use constant time and memory access for finding the PWE
These patches are available from https://w1.fi/security/2019-2/
- Update to wpa_supplicant/hostapd v2.8 or newer, once available
- Use strong passwords to prevent dictionary attacks
Signed-off-by: Stefan Lippers-Hollmann <s.l-h@gmx.de>
[bump PKG_RELEASE]
Signed-off-by: Jo-Philipp Wich <jo@mein.io>
SAE side-channel attacks
Published: April 10, 2019
Identifiers:
- VU#871675
- CVE-2019-9494 (cache attack against SAE)
Latest version available from: https://w1.fi/security/2019-1/
Vulnerability
Number of potential side channel attacks were discovered in the SAE
implementations used by both hostapd (AP) and wpa_supplicant
(infrastructure BSS station/mesh station). SAE (Simultaneous
Authentication of Equals) is also known as WPA3-Personal. The discovered
side channel attacks may be able to leak information about the used
password based on observable timing differences and cache access
patterns. This might result in full password recovery when combined with
an offline dictionary attack and if the password is not strong enough to
protect against dictionary attacks.
Cache attack
A novel cache-based attack against SAE handshake was discovered. This
attack targets SAE with ECC groups. ECC group 19 being the mandatory
group to support and the most likely used group for SAE today, so this
attack applies to the most common SAE use case. Even though the PWE
derivation iteration in SAE has protections against timing attacks, this
new cache-based attack enables an attacker to determine which code
branch is taken in the iteration if the attacker is able to run
unprivileged code on the victim machine (e.g., an app installed on a
smart phone or potentially a JavaScript code on a web site loaded by a
web browser). This depends on the used CPU not providing sufficient
protection to prevent unprivileged applications from observing memory
access patterns through the shared cache (which is the most likely case
with today's designs).
The attacker can use information about the selected branch to learn
information about the password and combine this information from number
of handshake instances with an offline dictionary attack. With
sufficient number of handshakes and sufficiently weak password, this
might result in full discovery of the used password.
This attack requires the attacker to be able to run a program on the
target device. This is not commonly the case on access points, so the
most likely target for this would be a client device using SAE in an
infrastructure BSS or mesh BSS.
The commits listed in the end of this advisory change the SAE
implementation shared by hostapd and wpa_supplicant to perform the PWE
derivation loop using operations that use constant time and memory
access pattern to minimize the externally observable differences from
operations that depend on the password even for the case where the
attacker might be able to run unprivileged code on the same device.
Timing attack
The timing attack applies to the MODP groups 22, 23, and 24 where the
PWE generation algorithm defined for SAE can have sufficient timing
differences for an attacker to be able to determine how many rounds were
needed to find the PWE based on the used password and MAC
addresses. When the attack is repeated with multiple times, the attacker
may be able to gather enough information about the password to be able
to recover it fully using an offline dictionary attack if the password
is not strong enough to protect against dictionary attacks. This attack
could be performed by an attacker in radio range of an access point or a
station enabling the specific MODP groups.
This timing attack requires the applicable MODP groups to be enabled
explicitly in hostapd/wpa_supplicant configuration (sae_groups
parameter). All versions of hostapd/wpa_supplicant have disabled these
groups by default.
While this security advisory lists couple of commits introducing
additional protection for MODP groups in SAE, it should be noted that
the groups 22, 23, and 24 are not considered strong enough to meet the
current expectation for a secure system. As such, their use is
discouraged even if the additional protection mechanisms in the
implementation are included.
Vulnerable versions/configurations
All wpa_supplicant and hostapd versions with SAE support (CONFIG_SAE=y
in the build configuration and SAE being enabled in the runtime
configuration).
Acknowledgments
Thanks to Mathy Vanhoef (New York University Abu Dhabi) and Eyal Ronen
(Tel Aviv University) for discovering the issues and for discussions on
how to address them.
Possible mitigation steps
- Merge the following commits to wpa_supplicant/hostapd and rebuild:
OpenSSL: Use constant time operations for private bignums
Add helper functions for constant time operations
OpenSSL: Use constant time selection for crypto_bignum_legendre()
SAE: Minimize timing differences in PWE derivation
SAE: Avoid branches in is_quadratic_residue_blind()
SAE: Mask timing of MODP groups 22, 23, 24
SAE: Use const_time selection for PWE in FFC
SAE: Use constant time operations in sae_test_pwd_seed_ffc()
These patches are available from https://w1.fi/security/2019-1/
- Update to wpa_supplicant/hostapd v2.8 or newer, once available
- In addition to either of the above alternatives, disable MODP groups
1, 2, 5, 22, 23, and 24 by removing them from hostapd/wpa_supplicant
sae_groups runtime configuration parameter, if they were explicitly
enabled since those groups are not considered strong enough to meet
current security expectations. The groups 22, 23, and 24 are related
to the discovered side channel (timing) attack. The other groups in
the list are consider too weak to provide sufficient security. Note
that all these groups have been disabled by default in all
hostapd/wpa_supplicant versions and these would be used only if
explicitly enabled in the configuration.
- Use strong passwords to prevent dictionary attacks
Signed-off-by: Stefan Lippers-Hollmann <s.l-h@gmx.de>
[bump PKG_RELEASE]
Signed-off-by: Jo-Philipp Wich <jo@mein.io>
With this change, the file is reduced from 5186 bytes to 4649 bytes that
its approximately 10.5 percent less memory consumption. For small
devices, sometimes every byte counts.
Also, all other protocol handler use tabs instead of spaces.
Signed-off-by: Florian Eckert <fe@dev.tdt.de>
This is sold as a dual-band 802.11ac range extender. It has a sliding
switch for Extender mode or Access Point mode, a WPS button, a recessed
Reset button, a hard-power button, and a multitude of LED's, some
multiplexed via an NXP 74AHC164D chip. The internal serial header pinout is
Vcc, Tx, Rx, GND, with GND closest to the corner of the board. You may
connect at 115200 bps, 8 data bits, no parity, 1 stop bit.
Specification:
- System-On-Chip: QCA9558
- CPU/Speed: 720 MHz
- Flash-Chip: Winbond 25Q128FVSG
- Flash size: 16 MiB
- RAM: 128 MiB
- Wireless No1: QCA9558 on-chip 2.4GHz 802.11bgn, 3x3
- Wireless No2: QCA99x0 chip 5GHz 802.11an+ac, 4x4
- PHY: Atheros AR8035-A
Installation:
If you can get to the stock firmware's firmware upgrade option, just feed
it the factory.img and boot as usual. As an alternative, TFTP the
factory.img to the bootloader.
Signed-off-by: Daniel Gimpelevich <daniel@gimpelevich.san-francisco.ca.us>
[whitespace fix in DTS and reorder of make variables]
Signed-off-by: Petr Štetiar <ynezz@true.cz>
Fix dbclient regression in 2019.77. After exiting the terminal would be left
in a bad state. Reported by Ryan Woodsmall
drop patch applied upstream:
010-tty-modes-werent-reset-for-client.patch
Signed-off-by: Hans Dedecker <dedeckeh@gmail.com>
We do not need to define an empty Build/Configure since
the default checks for existing ./configure and does nothing
in case nothing is found.
Similar for Build/Compile: we can remove the definition
when we only call the default.
Signed-off-by: Michael Heimpold <mhei@heimpold.de>
After getting rid of cryptsetup's heavy openssl dependency, there is now
the problem of missing RIPEMD160 support. RIPEMD160 is used for True/Vera
crypt volumes as well as old LUKS1 ones.
Signed-off-by: Rosen Penev <rosenp@gmail.com>
Currently leds migration scripts in ar71xx and lantiq share a lot of
logic and introducing leds migration to another target would mean
copying this code, again. Therefore add common logic to library in
base-files package.
Suggested-by: Petr Štetiar <ynezz@true.cz>
Signed-off-by: Petr Štetiar <ynezz@true.cz>
Signed-off-by: Tomasz Maciej Nowak <tomek_n@o2.pl>
* allowedips: initialize list head when removing intermediate nodes
Fix for an important regression in removing allowed IPs from the last
snapshot. We have new test cases to catch these in the future as well.
* tools: warn if an AllowedIP has a nonzero host part
If you try to run `wg set wg0 peer ... allowed-ips 192.168.1.82/24`, wg(8)
will now print a warning. Even though we mask this automatically down to
192.168.1.0/24, usually when people specify it like this, it's a mistake.
* wg-quick: add 'strip' subcommand
The new strip subcommand prints the config file to stdout after stripping
it of all wg-quick-specific options. This enables tricks such as:
`wg addconf $DEV <(wg-quick strip $DEV)`.
* tools: avoid unneccessary next_peer assignments in sort_peers()
Small C optimization the compiler was probably already doing.
* peerlookup: rename from hashtables
* allowedips: do not use __always_inline
* device: use skb accessor functions where possible
Suggested tweaks from Dave Miller.
* blake2s: simplify
* blake2s: remove outlen parameter from final
The blake2s implementation has been simplified, since we don't use any of the
fancy tree hashing parameters or the like. We also no longer separate the
output length at initialization time from the output length at finalization
time.
* global: the _bh variety of rcu helpers have been unified
* compat: nf_nat_core.h was removed upstream
* compat: backport skb_mark_not_on_list
The usual assortment of compat fixes for Linux 5.1.
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
The removed patches are now integrated in the upstream kernel.
Refresh all patches on top of the new backports release.
Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>
Tested-by: Daniel Engberg <daniel.engberg.lists@pyret.net>
Add U-Boot for NVIDIA Tegra based boards, with the first being CompuLab
TrimSlice. This is part of initial support for this board.
Signed-off-by: Tomasz Maciej Nowak <tomek_n@o2.pl>
New target introduces initial support for NVIDIA Tegra SoC based devices.
It focuses on Tegra 2 CPUs, for successors supporting NEON instruction
set the target should be split in two subtargets.
This initial commit doesn't create any device image, it's groundwork
for further additions.
Signed-off-by: Tomasz Maciej Nowak <tomek_n@o2.pl>
Commit 124ab1dc0a and 5523ee3459 introduced the assignment of the
group "tty" to /dev/tty* devices in order to support unprivileged
user access to serial devices.
However, due to an improperly rebased commit this feature broke.
This patch restores the lost hunk in hotplug.json file to
re-introduce this feature and also renames the existing "tty" group
to "dialout" as this is the more typical name for such a group
on desktop systems.
Fixes: 5209cfa534 ("procd: fix hotplug.json syntax")
Signed-off-by: Michael Heimpold <mhei@heimpold.de>
Acked-by: Jo-Philipp Wich <jo@mein.io>
OpenVPN as of 2.4.7 uses some OpenSSL APIs that are deprecated in
OpenSSL >= 1.1.0.
Signed-off-by: Magnus Kroken <mkroken@gmail.com>
Signed-off-by: Hans Dedecker <dedeckeh@gmail.com> [white space fix]
361b3e4 proto-shell: return error in case setup fails
a97297d interface: set interface in TEARDOWN state when checking link state
Signed-off-by: Hans Dedecker <dedeckeh@gmail.com>
Increase MAX_WAIT_FW_COMPLETE_ITERATIONS to 10000 as before commit
e5e0700 to prevent timeout as reported here: #308 (Original OP issue is
probably not related though as his post preceeds commit e5e0700).
compile/test target mvebu/mamba, rango
Signed-off-by: Kabuli Chana <newtownBuild@gmail.com>
[commit subject and message tweaks]
Signed-off-by: Petr Štetiar <ynezz@true.cz>
Release notes since last time:
Release notes for wave-1 / 10.1:
2019-03-28: Fix sometimes using bad TID for management frames
in htt-mgt mode. (Backported from wave2, looks
like bug would be the same though.)
Release notes for wave-2 / 10.4:
2019-03-28: Fix off-channel scanning while associated in
proxy-station mode.
2019-03-29: Fix sometimes sending mgt frames on wrong tid when
using htt-mgt. This bug has been around since I first
enabled htt-mgt mode.
Signed-off-by: Christian Lamparter <chunkeey@gmail.com>
c2cfe9d iwinfo: Fix 802.11ad channel to frequency
Fixes 9725aa271a ("iwinfo: update to latest git HEAD")
Signed-off-by: Daniel Golle <daniel@makrotopia.org>
ff1ded6 libfstools: Fix overflow of F2FS_MINSIZE constant
bc2c876 libfstools: Print error in case of loop blkdev failure
Signed-off-by: Petr Štetiar <ynezz@true.cz>
Instead of creating host-routes depending on fwmark as (accidentally)
pushed by commit
1e8bb50b93 ("wireguard: do not add host-dependencies if fwmark is set")
use a new config option 'nohostroute' to explicitely prevent creation
of the route to the endpoint.
Signed-off-by: Daniel Golle <daniel@makrotopia.org>
The 'fwmark' option is used to define routing traffic to
wireguard endpoints to go through specific routing tables.
In that case it doesn't make sense to setup routes for
host-dependencies in the 'main' table, so skip setting host
dependencies if 'fwmark' is set.
Signed-off-by: Daniel Golle <daniel@makrotopia.org>
The 4.14.108 bump introduced a missing dependency when building
specific netfilters.
Thsi was not seen as the error does not occur on all targets.
Thanks to Jo-Philipp Wich for providing the fix
Fixes: af6c86dbe5 ("kernel: bump 4.14 to 4.14.108")
Signed-off-by: Koen Vandeputte <koen.vandeputte@ncentric.com>
- limit ECC support to ec*-sha2-nistp256:
* DROPBEAR_ECC now provides only basic support for ECC
- provide full ECC support as an option:
* DROPBEAR_ECC_FULL brings back support for ec{dh,dsa}-sha2-nistp{384,521}
- update feature costs in binary size
Signed-off-by: Konstantin Demin <rockdrilla@gmail.com>
* option "keyfile" is more generic than "rsakeyfile".
* option "rsakeyfile" is considered to be deprecated and should be removed
in future releases.
* warn user (in syslog) if option "rsakeyfile" is used
* better check options ("rsakeyfile" and "keyfile"): don't append
"-r keyfile" to command line if file is absent (doesn't exist or empty),
warn user (in syslog) about such files
Signed-off-by: Konstantin Demin <rockdrilla@gmail.com>
Stefan Lippers-Hollmann