At the RSA 2020 conference, ESET specialists spoke about the new vulnerabilities Kr00k (CVE-2019-15126), which can be used to intercept and decrypt Wi-Fi traffic (WPA2).
According to analysts, any device that uses the solutions of Cypress Semiconductor and Broadcom, from laptops and smartphones to routers and IoT devices, is susceptible to this problem. Experts tested and confirmed the problem for iPhone, iPad, Mac, Amazon Echo and Kindle, Google Nexus, Samsung Galaxy, Xiaomi Redmi, Raspberry Pi 3, as well as Asus and Huawei Wi-Fi routers. In total, the problem threatens about a billion different gadgets.
The essence of the Kr00k problem comes down to encryption, which is used to protect data packets transmitted via Wi-Fi. Typically, such packets are encrypted with a unique key, which depends on the Wi-Fi password specified by the user. But for Broadcom and Cypress chips, this key is reset to zero if you initiate the process of dissociation (disassociation), that is, a temporary shutdown, which usually occurs due to a bad signal. Wi-Fi devices dissociate many times a day, and then automatically reconnect to a previously used network.
According to ESET experts, attackers can provoke the transition of the device into a prolonged state of dissociation and receive Wi-Fi packets intended for it. Then, by exploiting the Kr00k bug, attackers can decrypt Wi-Fi traffic using a “zero” key.
The Kr00k issue only affects Wi-Fi connections using WPA2-Personal and WPA2-Enterprise WiFi with AES-CCMP encryption. That is, the inclusion of the WPA3 protocol on the vulnerable device should protect against the attacks described by specialists. In addition, the vulnerability is unlikely to be useful to botnet operators for automated attacks, as it requires the attacker to be close to the victim (within the range of the Wi-Fi network).
Researchers notified manufacturers of the vulnerability two months ago, so by now many devices should have already received patches.
“Depending on the type of device, this may mean installing the latest OS or software updates (Android, Apple, and Windows devices; some IoT devices), but you may also need a firmware update (access points, routers, and some IoT devices),” experts say .
Experts note that the Kr00k problem is in many ways similar to the sensational KRACK vulnerability, discovered in 2017 and forcing manufacturers to hurry up with the transition to WPA3, as well as the DragonBlood problem, which already posed a threat to WPA3. At the same time, it is emphasized that Kr00k is in many respects different from its “progenitors” and it will be easier to correct the consequences in this case.