Belgium’s KU Leuven researchers unveiled a critical flaw in the IEEE 802.11 Wi-Fi standard, potentially jeopardizing users’ security by allowing attackers to manipulate their choice of wireless network connections. The vulnerability, dubbed CVE-2023-52424, impacts all Wi-Fi clients regardless of their operating system and affects networks using WPA3, WEP, and 802.11X/EAP protocols. The researchers, in collaboration with VPN review site Top10VPN, disclosed the details of the flaw ahead of an upcoming presentation in Seoul, South Korea.
The root cause of this flaw lies in the lack of mandatory authentication for a network’s Service Set Identifier (SSID) in the IEEE 802.11 standard. The SSID distinguishes wireless access points and networks, aiding in identification. However, the standard does not always require the SSID to be authenticated during client connections, leaving room for exploitation by attackers.
In a statement, KU Leuven researchers Héloïse Gollier and Mathy Vanhoef explained that clients could be deceived into connecting to a different protected Wi-Fi network than the intended one, displaying a fake SSID on the user interface. Vanhoef, known for uncovering significant Wi-Fi vulnerabilities like Dragonblood in WPA3 and Krack key reinstallation attacks in WPA2, highlighted the severity of the new design flaw.
The researchers detailed that modern Wi-Fi networks rely on a 4-way handshake for authentication and encryption key negotiation, using a shared Pairwise Master Key (PMK). However, the absence of the SSID in the key derivation process allows attackers to set up rogue access points, posing as trusted networks to downgrade victims to less secure connections.
For exploitation of this weakness, specific circumstances must align, such as the presence of two Wi-Fi networks within an organization sharing credentials but differing in security levels. Attackers in close proximity could execute man-in-the-middle attacks by tricking devices into connecting to a rogue access point with a matching SSID, potentially exposing victims to known vulnerabilities like Krack and undermining VPN protections.
Top10VPN highlighted three defense mechanisms against SSID confusion attacks: mandating SSID authentication in the IEEE 802.11 standard, enhancing beacon protection to detect unauthorized SSID changes, and refraining from reusing credentials across different SSIDs. The researchers emphasized the urgency for updates at both standard and organizational levels to mitigate the risks posed by this critical Wi-Fi flaw.
In conclusion, the newly discovered Wi-Fi design flaw underscores the importance of implementing robust security measures to safeguard wireless network connections and prevent potential exploitation by malicious actors. Researchers continue to advocate for proactive measures to address vulnerabilities and enhance the overall security posture of Wi-Fi networks globally.