Google Project Zero has disclosed the details of two critical remote code execution vulnerabilities affecting the Broadcom Wi-Fi chips found in many Android and iOS devices.
The flaws, identified as CVE-2017-11120 and CVE-2017-11121, were patched in Android on September 5 with this month’s security updates and in iOS on September 19 with the release of iOS 11. tvOS versions prior to 11 are also impacted.
Until now, the only details known about these vulnerabilities were the fact that they are memory corruptions that could allow arbitrary code execution, and that they affect Broadcom Wi-Fi drivers.
Advisories made public late on Monday by Gal Beniamini of Google Project Zero provide additional details about the flaws and the Broadcom chips they affect.
“Broadcom produces Wi-Fi HardMAC SoCs which are used to handle the PHY and MAC layer processing. These chips are present in both mobile devices and Wi-Fi routers, and are capable of handling many Wi-Fi related events without delegating to the host OS,” the researcher explained.
The weakness tracked as CVE-2017-11120 is an out-of-bounds write issue that exists due to the way the Broadcom firmware handles the Neighbor Report Response frame of the Radio Resource Management standard. By injecting a large value into one of the buffers, an attacker within Wi-Fi range can achieve arbitrary code execution.
Beniamini said he found the problematic code in different versions of the Wi-Fi firmware, including on iPhone 7 and Samsung S7 Edge smartphones. The researcher has published a proof-of-concept (PoC) exploit for the iPhone 7. He believes the attack, which requires the targeted device to connect to a Wi-Fi network set up by the attacker, should work on all versions prior to iOS 11.
“Upon successful execution of the exploit, a backdoor is inserted into the firmware, allowing remote read/write commands to be issued to the firmware via crafted action frames (thus allowing easy remote control over the Wi-Fi chip),” he explained.
The second flaw, CVE-2017-11121, allows remote code execution due to multiple buffer overflows when handling reassociation responses via the Fast BSS Transition feature. Beniamini has provided detailed technical information on how the vulnerability can be exploited, but he has not released an actual exploit.
This was not the first time Beniamini discovered critical Android and iOS vulnerabilities introduced by Broadcom Wi-Fi chips. In April, the researcher reported finding several remote code execution, privilege escalation and information disclosure flaws that could have been exploited without user interaction.
Another similar vulnerability, dubbed “Broadpwn,” was discovered earlier this year by Exodus Intelligence researcher Nitay Artenstein.