Security Experts:

QCT Servers Affected by 'Pantsdown' BMC Vulnerability

Servers made by Quanta Cloud Technology (QCT) are affected by the baseboard management controller (BMC) vulnerability known as CVE-2019-6260 and “Pantsdown.”

The vulnerability, whose details were disclosed in early 2019, affects ASPEED ast2400 and ast2500 BMC hardware and firmware implementing Advanced High-performance Bus (AHB) bridges, which allow arbitrary read and write access to the BMC's physical address space from the host and — in some cases — from the network.

Several major manufacturers released advisories at the time to inform their customers about the critical vulnerability, including Supermicro, IBM, HP and Gigabyte.

Firmware and hardware security company Eclypsium determined last year that QCT servers had still been affected by the Pantsdown vulnerability. QCT’s data center solutions are used by major companies such as Facebook and Rackspace, according to QCT’s Wikipedia page.

Eclypsium’s researchers have developed a proof-of-concept (PoC) exploit to show how an unsophisticated attacker with remote access to the operating system could exploit the vulnerability for arbitrary code execution within the BMC of a targeted server.

“This vulnerability can provide an attacker with full control over the server including the ability to propagate ransomware, stealthily steal data, or disable the BMC or the server itself,” Eclypsium explained. “Additionally, by gaining code execution in the BMC, attackers could steal the BMC credentials, which could allow the attack to spread to other servers in the same IPMI group.”

According to the company, an attacker who gains access to a server with a vulnerable BMC can conduct various activities, including modify the BMC flash for persistence, modify the UEFI to plant persistent malware, modify the kernel and inject malware into a running host, inject arbitrary keyboard or mouse events, move laterally to other devices on the network, use virtual USB devices to route traffic, or brick the device.

The cybersecurity firm informed Quanta about the vulnerability in October 2021. The vendor has informed Eclypsium that new firmware addressing the flaw is privately available to customers, but it will not be made public.

It’s unclear how many customers have actually installed the firmware patches. Eclypsium conducted its tests on a QuantaGrid D52B rackmount server, which they updated with the latest publicly available firmware.

SecurityWeek has reached out to the vendor for comment and will update this article if the company responds.

Eclypsium warns that BMC vulnerabilities should not be ignored, particularly with the emergence of threats like iLOBleed, a sophisticated rootkit that is designed to target the BMC firmware of HP servers.

Related: BIOSConnect Flaws Haunt Millions of Dell Computers

Related: USBAnywhere: BMC Flaws Expose Supermicro Servers to Remote Attacks

Related: Servers Can Be Bricked Remotely via BMC Attack

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Eduard Kovacs (@EduardKovacs) is a contributing editor at SecurityWeek. He worked as a high school IT teacher for two years before starting a career in journalism as Softpedia’s security news reporter. Eduard holds a bachelor’s degree in industrial informatics and a master’s degree in computer techniques applied in electrical engineering.