Firmware security company Binarly this week disclosed the details of several vulnerabilities that impact the Unified Extensible Firmware Interface (UEFI) of multiple Dell enterprise laptop models.
On March 10, Dell announced patches for five SMM vulnerabilities in the UEFI – the successor of the BIOS firmware interface – of 45 device models, including multiple Alienware, Inspiron, and Vostro laptop models.
Tracked as CVE-2022-24415, CVE-2022-24416, CVE-2022-24419, CVE-2022-24420, and CVE-2022-24421, the high-severity security bugs (CVSS score of 8.2) are described as improper input validation issues that could allow a local, authenticated attacker to execute arbitrary code on the vulnerable system.
Starting mid-February, Dell has made UEFI updates available for all of the impacted devices, including laptops, edge gateways, and embedded box PCs. Customers are advised to apply the updates as soon as possible.
Three of the resolved issues – namely CVE-2022-24419, CVE-2022-24420, and CVE-2022-24421 – were identified by security researchers with Binarly, who this week revealed that the flaws are actually versions of the UsbRt vulnerabilities initially detailed in 2016.
Dubbed Aptiocalypsis, the UsbRt bugs could be exploited to run arbitrary System Management Mode (SMM) code to disable flash write protections and inject persistent backdoors into firmware.
The Aptiocalypsis vulnerabilities impacted devices running AMI-based firmware and multiple variants of the bugs were identified over time. The bugs that Dell recently patched prove that similar bugs continue to plague current devices, although more than half a decade has passed since the initial discovery.
“UsbRt bugs have an almost-six-year-old history of successful and repeatable exploitation,” Binarly notes, pointing not only to the complexity of the firmware supply chain, but also to the inefficiency of the existing tools to successfully identify firmware-specific security defects.
“The majority of security practices revolve around the compliance checklists with poorly configured static analysis tools and running an antivirus scan of the entire code base snapshot before release. This fundamental misunderstanding of design failures leads to an expansion of code complexity and keeps devices in a perpetual state of exposure,” Binarly says.