Putting this in Tech Talk because I feel it’s really important for those of you who have routers/repeaters or cellphones and use WPA2.
Severe flaw in WPA2 protocol leaves Wi-Fi traffic open to eavesdropping
KRACK attack allows other nasties, including connection hijacking and malicious injection.
An air of unease set into the security circles on Sunday as they prepared for the disclosure of high-severe vulnerabilities in the Wi-Fi Protected Access II protocol that make it possible for attackers to eavesdrop Wi-Fi traffic passing between computers and access points.
The proof-of-concept exploit is called KRACK, short for Key Reinstallation Attacks. The research has been a closely guarded secret for weeks ahead of a coordinated disclosure that’s scheduled for 8 a.m. Monday, east coast time. An advisory the US CERT recently distributed to about 100 organizations described the research this way:
US-CERT has become aware of several key management vulnerabilities in the 4-way handshake of the Wi-Fi Protected Access II (WPA2) security protocol. The impact of exploiting these vulnerabilities includes decryption, packet replay, TCP connection hijacking, HTTP content injection, and others. Note that as protocol-level issues, most or all correct implementations of the standard will be affected. The CERT/CC and the reporting researcher KU Leuven, will be publicly disclosing these vulnerabilities on 16 October 2017.
According to a researcher who has been briefed on the vulnerability, it works by exploiting a four-way handshake that’s used to establish a key for encrypting traffic. During the third step, the key can be resent multiple times. When it’s resent in certain ways, a cryptographic nonce can be reused in a way that completely undermines the encryption.
Microsoft has a client side mitigation patch available, make sure you are up to date (patch tuesday release)
Many Linux vendors have updates available (wpa_supplicant needs to get patched, hostapd if run an AP and have Fast BSS Transition enabled)
Currently practically all Android devices are vulnerable, WP unknown, iOS unknown.
Routers that offer 802.11r are vulnerable
Repeaters are vulnerable
Worst case scenarios? Rogue DHCP server injected into WLAN that does DNS hijacking, HTTPS interception for sites that do not employ key pinning and all HTTP traffic is fully readable.
Be up to date, gents (and ladies).