UEFI Shell Vulnerabilities Could Let Hackers Bypass Secure Boot on 200,000+ Laptops

Hackers can exploit vulnerabilities in signed UEFI shells to bypass Secure Boot protections on over 200,000 Framework laptops and desktops.

According to Eclypsium, these vulnerabilities expose fundamental flaws in how modern systems trust boot components, potentially enabling persistent malware infections that evade detection.

Disclosed recently to Framework, the issues stem from legitimate diagnostic tools that, despite being signed by trusted authorities like Microsoft, include commands powerful enough to dismantle core security safeguards.

As pre-operating system attacks grow more common, echoing threats like BlackLotus and Bootkitty, this discovery underscores the risks lurking in the firmware layer we often overlook.

UEFI shells act as pre-boot command-line environments, akin to a supercharged terminal with unrestricted hardware access. Designed for IT pros to diagnose hardware, update firmware, configure settings, or test drivers, they run before the OS loads, granting privileges far beyond typical admin rights.

The problem arises from their integration into the Secure Boot chain of trust. Microsoft’s UEFI Certificate Authority serves as the root anchor, signing third-party tools that original equipment manufacturers (OEMs) embed in firmware.

Once signed, these shells execute without scrutiny, even on systems enforcing Secure Boot to block unsigned code.

Eclypsium’s deep dive revealed that many such shells harbor the “mm” command for memory modification. This tool lets users read or write to any system memory address, bypassing protections like address space layout randomization or data execution prevention features absent in the pre-OS world.

While useful for diagnostics, it becomes a hacker’s dream when scripted to run automatically via startup files, persisting across reboots without alerting the OS.

The technique targets the Security Architectural Protocol, which verifies signatures during boot. Eclypsium researchers Jesse Michael and Mickey Shkatov, in their DEF CON 30 demo, outlined a straightforward path: enumerate system handles to find the protocol’s memory address, then use “mm” to overwrite its pointer, nulling it out or forcing a false “success” return.

A simple command like “mm 0x[target_address] 0x00000000 -w 8 -MEM” disables checks, allowing unsigned bootkits or rootkits to load freely while Secure Boot appears intact.

Testing on Framework devices confirmed the issue. Using tools like sbverify and custom Python scripts with the pefile library, Eclypsium scanned EFI files for “mm” indicators, flagging high-risk binaries.

QEMU-based automation further validated execution. This isn’t theoretical; gamers already pay for similar cheats using Microsoft-signed components, and nation-state actors or ransomware groups like those behind HybridPetya could weaponize it for espionage or sabotage.

Affected models span Framework’s lineup, from 11th Gen Intel Core to AMD Ryzen AI series, impacting roughly 200,000 units.

Product	BIOS Version with Limited Shell	BIOS Version with DBX Update
Framework13 11th Gen Intel Core	Vulnerable: Fixed planned in 3.24	Vulnerable: Fixed planned in 3.24
Framework13 12th Gen Intel Core	Fixed in 3.18	Fix planned for 3.19 (TBD)
Framework13 13th Gen Intel Core	Fixed in 3.08	Fixed in 3.09
Framework13 Intel Core Ultra Series 1	Fixed in 3.06	Fixed in 3.06
Framework13 AMD Ryzen 7040 Series	Fixed in 3.16	Fixed in 3.16
Framework13 AMD Ryzen AI 300 Series	Fixed in 3.04	Planned in 3.05 (TBD)
Framework16 AMD Ryzen 7040 Series	Fixed in 3.06 (Beta)	Fixed in 3.07
Framework Desktop AMD Ryzen AI 300 MAX	Fixed in 3.01	Planned in 3.03

Framework has rolled out fixes by stripping risky commands from shells and updating DBX revocation lists to blacklist vulnerable versions. Users can apply BIOS updates or delete Framework DB keys via setup menus for immediate protection.

Past incidents, like CVE-2022-34302 and CVE-2024-7344, highlight this as an industry-wide crisis, prompting calls to bar shells from Secure Boot chains in EDK2 specs.

Defenses include regular DBX updates, BIOS passwords, custom keys, and firmware scanning tools. As Eclypsium warns, implicit trust in signatures blinds us to supply chain perils.

With firmware attacks escalating, organizations must prioritize this “below-OS” surface to avoid catastrophic breaches. The era of treating signed code as inherently safe has ended; verification is now essential.

Follow us on Google News, LinkedIn, and X for daily cybersecurity updates. Contact us to feature your stories.