Kaspersky Lab claimed on Monday that it had uncovered a sophisticated supply chain attack using the live update utility, with the attack having taken place between June and November 2018. The ASUS utility is used to update the BIOS, UEFI, drivers and applications.
Duo Security's Darren Kemp, Chris Czub and Mikhail Davidov wrote in their study: "ASUS appears to be one of the worst OEMs we looked at, providing attackers with functionality that can only be referred to as remote code execution as a service.
"The 'Asus Live Update' software contains no security features whatsoever, allowing for easy exploitation. Oh yeah, we should probably mention they use this atrocity to push out BIOS updates too."
"By intercepting the manifest, an attacker can rewrite it to execute arbitrary commands with administrative privileges," the three researchers said.
- "An example MITM (man-in-the-middle attack is as follows:
- "An increased version number is presented, forcing the processing of the update.
- "Set the update severity to 'critical' so that it gets processed immediately and without any user intervention.
- "Change the execute parameter to be whatever we would like, such as 'cmd.exe%%/K calc'."
Kemp, Czub and Davidov also pointed out that there was weak encryption used by ASUS and no authenticode validation.
They questioned why TLS support wasn't used with certificate pinning to help ensure the authenticity and integrity of executables and manifests.
From examining a snippet of coded, they found that the company had tried to add TLS support, but didn’t quite finish it.
The trio also looked at other OEMs like Dell, HP, Lenovo and Acer. Duo Security is now owned by Cisco.