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1. Gigabyte american megatrends bios update install#
2. Gigabyte american megatrends bios update update#
3. Gigabyte american megatrends bios update full#

Figure 2 shows the CHIPSEC output of a system which has enabled BIOS Lock Enable (BLE) and SMM BIOS Write Protection (SMM_BWP) to prevent modifications to the BIOS:įigure 2: CHIPSEC Output of a Write Protected BIOS Write-protection mechanisms exist to prevent attackers from modifying the firmware however, the affected systems do not enable them.

Gigabyte american megatrends bios update install#

A vulnerable SMI handler allows the attacker to execute code in SMM mode (ring -2) where he finally can bypass any write protection mechanisms and install a backdoor into the system's firmware. From there, the attacker elevates his privileges by exploiting the kernel or a kernel module such as Capcom.sys to execute code in ring 0. The attacker gains user-mode execution through an application vulnerability such as a browser exploit or a malicious Word document with an embedded script.

Gigabyte american megatrends bios update full#

We have reported these vulnerabilities to the vendor (see our full disclosure timeline at the end of this post).įirmware backdoors are difficult to detect because they execute in the early stages of the boot process and they can persist across operating system (OS) re-installations:įigure 1: Attack Flow Chart to Install a UEFI Backdoor These vulnerabilities allow an attacker to elevate privileges, execute arbitrary code in System Management Mode (SMM), and install a backdoor at the firmware level. Today at BlackHat Asia 2017, we are disclosing two vulnerabilities in two different models of the GIGABYTE BRIX platform: Physical access requirements are a thing of the past these low-level implants can be installed remotely by exploiting vulnerabilities in the underlying UEFI system. The HackingTeam, Snowden, Shadow Brokers, and Vault7 leaks have revealed that UEFI/BIOS implants aren't just a theoretical concept, but have actually been weaponized by nation states to conduct cyber-espionage. So I fully expect that once F35 is finalized, that it too will be a one-way street, and they just happened to tip their hand a bit early by posting then removing it from the beta builds for other boards.Īsus has been using AMI's BIOS capsules for years, so Gigabyte switching now after their AMI repo was compromised tells me this is entirely about signature validation, and they want to make sure nobody can flash malicious BIOS builds that may potentially be able to be built with the stolen data.Earlier this month, we teased a proof of concept for UEFI ransomware, which was presented at RSA Conference 2017.

Gigabyte american megatrends bios update update#

Given the researchers credited, it's possible it's another UEFI exploit, but I find the timing too coincidental, and the fact that it affects both AMD and Intel says it's more about the potential for the stolen data to be used to create malicious updates, rather than a specific vulnerability.Īlso, on the Intel boards that have received a FINAL update (ie not a beta that ends in a letter), the "once installed you can't go back" message is again present.

Given that they switched to the capsules for Intel boards as well, it's almost certainly due to the ransomware attack that compromised their local AMI BIOS repo.