Weak password WPA-Personal and WPA2-Personal remain vulnerable to
password cracking attacks if users rely on a
weak password or passphrase. WPA passphrase hashes are seeded from the SSID name and its length;
rainbow tables exist for the top 1,000 network SSIDs and a multitude of common passwords, requiring only a quick lookup to speed up cracking WPA-PSK. Brute forcing of simple passwords can be attempted using the
Aircrack Suite starting from the four-way authentication handshake exchanged during association or periodic re-authentication. WPA3 replaces cryptographic protocols susceptible to off-line analysis with protocols that require interaction with the infrastructure for each guessed password, supposedly placing temporal limits on the number of guesses. significantly improved upon the
WPA-TKIP attacks of Erik Tews and Martin Beck. They demonstrated how to inject an arbitrary number of packets, with each packet containing at most 112 bytes of payload. This was demonstrated by implementing a
port scanner, which can be executed against any client using
WPA-TKIP. Additionally, they showed how to decrypt arbitrary packets sent to a client. They mentioned this can be used to hijack a
TCP connection, allowing an attacker to inject malicious
JavaScript when the victim visits a website. In contrast, the Beck-Tews attack could only decrypt short packets with mostly known content, such as
ARP messages, and only allowed injection of 3 to 7 packets of at most 28 bytes. The Beck-Tews attack also requires
quality of service (as defined in
802.11e) to be enabled, while the Vanhoef-Piessens attack does not. Neither attack leads to recovery of the shared session key between the client and
Access Point. The authors say using a short rekeying interval can prevent some attacks but not all, and strongly recommend switching from
TKIP to AES-based
CCMP. Halvorsen and others show how to modify the Beck-Tews attack to allow injection of 3 to 7 packets having a size of at most 596 bytes. The downside is that their attack requires substantially more time to execute: approximately 18 minutes and 25 seconds. In other work Vanhoef and Piessens showed that, when WPA is used to encrypt broadcast packets, their original attack can also be executed. This is an important extension, as substantially more networks use WPA to protect
broadcast packets, than to protect
unicast packets. The execution time of this attack is on average around 7 minutes, compared to the 14 minutes of the original Vanhoef-Piessens and Beck-Tews attack. The vulnerabilities of TKIP are significant because WPA-TKIP had been held before to be an extremely safe combination; indeed, WPA-TKIP is still a configuration option upon a wide variety of wireless routing devices provided by many hardware vendors. A survey in 2013 showed that 71% still allow usage of TKIP, and 19% exclusively support TKIP. Users have been urged to turn off the WPS feature, although this may not be possible on some router models. Also, the PIN is written on a label on most Wi-Fi routers with WPS, which cannot be changed if compromised. In 2018, the Wi-Fi Alliance introduced Wi-Fi Easy Connect as a new alternative for the configuration of devices that lack sufficient user interface capabilities by allowing nearby devices to serve as an adequate UI for network provisioning purposes, thus mitigating the need for WPS.
MS-CHAPv2 and lack of AAA server CN validation Several weaknesses have been found in
MS-CHAPv2, some of which severely reduce the complexity of brute-force attacks, making them feasible with modern hardware. In 2012 the complexity of breaking MS-CHAPv2 was reduced to that of breaking a single
DES key (work by
Moxie Marlinspike and Marsh Ray). Moxie advised: "Enterprises who are depending on the mutual authentication properties of MS-CHAPv2 for connection to their WPA2 Radius servers should immediately start migrating to something else." Tunneled EAP methods using TTLS or PEAP which encrypt the MSCHAPv2 exchange are widely deployed to protect against exploitation of this vulnerability. However, prevalent WPA2 client implementations during the early 2000s were prone to misconfiguration by end users, or in some cases (e.g.
Android), lacked any user-accessible way to properly configure validation of AAA server certificate CNs. This extended the relevance of the original weakness in MSCHAPv2 within
MiTM attack scenarios. Under stricter compliance tests for WPA2 announced alongside WPA3, certified client software will be required to conform to certain behaviors surrounding AAA certificate validation.
Predictable Group Temporal Key (GTK) In 2016 it was shown that the WPA and WPA2 standards contain a proposed example
random number generator (RNG) that is insecure.
KRACK attack In October 2017, details of the
KRACK (Key Reinstallation Attack) attack on WPA2 were published. The KRACK attack is believed to affect all variants of WPA and WPA2; however, the security implications vary between implementations, depending upon how individual developers interpreted a poorly specified part of the standard. Software patches can resolve the vulnerability but are not available for all devices. KRACK exploits a weakness in the WPA2 4-Way Handshake, a critical process for generating encryption keys. Attackers can force multiple handshakes, manipulating key resets. By intercepting the handshake, they could decrypt network traffic without cracking encryption directly. This poses a risk, especially with sensitive data transmission. Manufacturers have released patches in response, but not all devices have received updates. Users are advised to keep their devices updated to mitigate such security risks. Regular updates are crucial for maintaining network security against evolving threats. These included side-channel attacks potentially revealing sensitive user information and implementation weaknesses in EAP-pwd and SAE. Concerns were also raised about the inadequate security in transitional modes supporting both WPA2 and WPA3. In response, security updates and protocol changes are being integrated into WPA3 and EAP-pwd to address these vulnerabilities and enhance overall Wi-Fi security.
FragAttacks In May 2021
FragAttacks, a set of new security vulnerabilities, were revealed, affecting Wi-Fi devices and enabling attackers within range to steal information or target devices. These include design flaws in the Wi-Fi standard, affecting most devices, and programming errors in Wi-Fi products, making almost all Wi-Fi products vulnerable. The vulnerabilities impact all Wi-Fi security protocols, including WPA3 and WEP. Exploiting these flaws is complex but programming errors in Wi-Fi products are easier to exploit. Despite improvements in Wi-Fi security, these findings highlight the need for continuous security analysis and updates. In response, security patches were developed, and users are advised to use HTTPS and install available updates for protection. ==References==