Secure Boot bypassed: 200,000 Linux Framework PCs at risk

Technical Analysis of the Flaw Leading to Secure Boot Bypass on Framework Linux Laptops

In 2025, the security of UEFI Secure Boot, or Secure Boot, was compromised by a vulnerability detected on nearly 200,000 laptops from the American brand Framework, a renowned specialist in its modular Linux machines. This flaw concerns a legitimately signed UEFI component, which integrates a “memory modify” (mm) command, providing direct read and write access to system memory.

Specifically, this function is originally used for low-level diagnostics and firmware debugging. However, it can be exploited to alter the gSecurity2 variable, a key component in validating UEFI module signatures. By replacing the pointer to this variable with NULL or a function that systematically returns a positive validation, an attacker can disable digital signature verification, opening the door to unauthorized code execution during the boot phase. This tampering is dangerous because it compromises the UEFI Secure Boot chain of trust, the foundation of hardware-software security that prevents malware injection before the operating system, such as Ubuntu, Fedora, or Debian, takes over. Furthermore, this attack can be automated by a boot script, facilitating persistence even after reinstalling the operating system. mm Command:Direct memory access for diagnostic purposes. gSecurity2 Variable: Controls UEFI signature verification.

Impact:

Disabled signature checking, opening the door to malicious bootkits. Machines Affected:
Framework laptops, recent models with various Intel and AMD generations. Persistence:
Persistence via automation in boot sequences. This case expands a problem already observed on other architectures such as certain HP, Dell, Lenovo, ASUS, Acer, and MSI models where poor attention to firmware security has allowed various Secure Boot bypasses, also affecting popular Linux distributions.
discover the risks associated with activating secure boot under Linux, its impacts on security, system compatibility and the precautions to take to protect your IT environment. Examples of bootkits exploiting this flaw
The practical consequences of this vulnerability are serious since they allow the loading of bootkits such as BlackLotus

, Or

Bootkitty . These malware were designed to run at the UEFI level, which gives them immunity to most operating system-side security mechanisms.HybridPetya, for example, is a threat that combines various evasion techniques taken from Petya and NotPetya ransomware, capable of bypassing UEFI security. Once installed, it can permanently compromise an Ubuntu or Fedora system, by interposing itself in the boot process before loading the Linux kernel itself. These bootkits also make it possible to maintain a persistent presence on the machine, which makes it difficult to detect and remove them using traditional antivirus tools or by reinstalling the system cleanly. Thus, the attack is not limited to a single step but can persist despite classic cleaning attempts.BlackLotus: Persistent UEFI bootkit targeting Linux systems.HybridPetya:

Advanced ransomware bypassing Secure Boot.

Bootkitty:

UEFI malware capable of undetected firmware changes. Persistent :
Resists typical system reinstallations. Impact :
Significantly reduced secure system recovery capabilities. https://www.youtube.com/watch?v=_bY7MxD91P8
UEFI Secure Boot Mechanisms and Their Impact on Linux Distributions To understand the implications of this flaw, it is essential to review the functioning of
Secure Boot , a mechanism introduced with the Unified Extensible Firmware Interface (UEFI). Secure Boot validates that each component loaded at boot is signed with an approved key, thus preventing the execution of unauthorized and malicious software.

In Linux environments, particularly on major distributions like Debian, Ubuntu, or Fedora, Secure Boot is often a difficult obstacle to manage. Developers and users must have compliant signature envelopes to be able to load their custom kernels or modules. In this context, Framework and other manufacturers integrate these signatures into the firmware, but any flaw in the chain of trust, such as the one induced by the mm command, compromises the entire system security.

The process works as follows:

At boot, the UEFI firmware verifies the digital signature of the loaders and modules using the keys stored in its secure database. If the signature is valid, loading continues. Otherwise, the block prevents the insecure software from starting. If critical memory related to this verification, such as gSecurity2, is changed to NULL, this validation is disabled, rendering Secure Boot ineffective.EFI System Partition (ESP):

Contains signed loaders.

DB and DBX:

Databases for approved and revoked keys.
Importance for Linux:
Signatures are required to boot into Secure Boot.

Vulnerability: Disabling signature verification through memory corruption.
Consequence: Possible introduction of malicious modules without detection.
For users wishing to experiment with or deploy Linux without compromising security, it’s worth considering secure USB multiboot solutions or even mastered dual boot configurations, particularly on Framework computers. Practical guides such as Linux USB Multiboot Solutions
and Microsoft Dual Boot Linux
are invaluable for navigating mixed environments without compromising UEFI security. Discover the risks associated with enabling secure boot on Linux: compatibility, security, and impact on the installation of certain systems or drivers.

Firmware and the Role of Signed Keys in the Linux Context Signing keys (DB) are an essential building block for authorizing Linux modules such as the kernel and GRUB to launch under Secure Boot. However, a weakness in firmware management or a compromised key can completely invalidate these protections. Regular updates of DB and DBX (revoked keys) by the manufacturer, such as Framework, are crucial. For example, Framework has planned patches for each affected model, with firmware updates from version 3.01 to 3.24, as well as associated DBX database updates to revoke vulnerable keys. Failure to maintain this maintenance can result in prolonged exposure to critical risks. Firmware Update: Patches to neutralize the dangerous mm command. DBX Updates:

Importance:

Prevent exploitation by persistent bootkits.

Affected Models:

Framework 13 (Intel and AMD), Framework 16, and Desktop Ryzen AI. Speed of Action:
Essential to limit the scope of the threat. https://www.youtube.com/watch?v=2Lrz5hsesVw
How to effectively protect your Linux Framework system against this Secure Boot vulnerability Prompt application of Framework updates is the first line of defense against this vulnerability. For those who cannot yet take advantage of the patch, several intermediate measures are recommended:
Physical Access Prevention: The risk increases if an attacker can physically access the machine.
Deleting the Vulnerable DB Key: Temporarily remove the vulnerable Framework key via the BIOS.

Temporarily Disabling Secure Boot:

This option should be used with caution and only in controlled situations.

Firmware Monitor:

Regularly monitor updates on official Framework channels. In a broader context, validating and controlling the use of privileges with Linux tools such as
sudo is essential, as an attacker with local administrator rights can exploit this flaw to anchor a deep compromise. For administrators and advanced users, it is also recommended to test new secure Linux images for ARM architectures such as
Ubuntu on Snapdragon , or to use solutions that allow you to
try Linux without disrupting Windows via virtualized environments or live USB, thus limiting the risk of direct exposure.

Framework Firmware Update: Apply official patches promptly. Restricted Physical Access:

Secure hardware against unauthorized access. Strict Root Account Management:Limit privileges via sudo and other tools.Test Secure Linux Environments: Use recent or alternative distributions live.

Continuous Monitoring: Stay informed of vulnerabilities in Framework and other players.
Discover the risks associated with enabling secure boot in Linux: compatibility, security, and tips to protect your system while ensuring optimal use of your Linux distribution. Best Practices to Avoid UEFI Attacks on Linux
Vulnerabilities in UEFI firmware, although rare, have a major impact on overall security. Here are a few tips and best practices to strengthen protection: Use signed and validated firmware:
Always prefer well-known and regularly maintained models. Apply system and firmware updates:
Never ignore critical patches. Properly configure Secure Boot:

Ensure the authorized key database is up to date.

Restrict physical and administrative access:

Protect administrator credentials and hardware.

Use system auditing tools: Check firmware consistency, for example, with Linux-compatible open source tools.
Avoid misconfigured dual boots: Refer to reliable guides such as
this dual boot tutorial . In the Linux world, whether for Framework or other brands such as Dell, HP, Lenovo, ASUS, Acer, and MSI, it’s important to adopt a proactive security policy combined with constant technological monitoring. These measures minimize the risks associated with firmware attacks and Secure Boot bypass.
https://www.youtube.com/watch?v=nS3mQm2O434