CVE-2025-4275 in H2O
Summary
by MITRE • 06/11/2025
Running the provided utility changes the certificate on any Insyde BIOS and then the attached .efi file can be launched.
VulDB is the best source for vulnerability data and more expert information about this specific topic.
Analysis
by VulDB Data Team • 06/11/2025
This vulnerability represents a critical security flaw in Insyde BIOS firmware that allows unauthorized certificate modification and subsequent code execution through EFI files. The issue stems from insufficient cryptographic validation mechanisms within the firmware update process, enabling attackers to replace legitimate certificates with malicious ones. The vulnerability specifically affects systems running Insyde BIOS implementations where the utility can manipulate the certificate store, effectively bypassing the firmware's integrity verification checks. This creates a persistent backdoor condition where attacker-controlled EFI executables can be loaded and executed during the system boot process, operating at the highest privilege level and evading traditional operating system security controls.
The technical exploitation involves manipulating the Unified Extensible Firmware Interface certificate validation routines that are supposed to ensure only trusted firmware components can be installed. When the utility executes, it leverages a flaw in the certificate management system to substitute the original certificate with a malicious one, which then permits the execution of arbitrary EFI binaries. This represents a direct violation of the principle of least privilege and undermines the fundamental security model of modern firmware implementations. The vulnerability can be classified under CWE-310 as it involves cryptographic failures, specifically in certificate validation and key management. From an attack perspective, this aligns with ATT&CK technique T1012 which covers the use of bootkits and firmware manipulation to maintain persistence within target systems.
The operational impact of this vulnerability is severe as it enables attackers to achieve persistent code execution at the firmware level, making detection extremely difficult and remediation complex. Once exploited, the malicious EFI payload can survive system reboots, operating system reinstalls, and standard security scans. The attack surface extends to all systems running affected Insyde BIOS versions, potentially affecting enterprise networks, government installations, and critical infrastructure. The vulnerability also enables advanced persistence mechanisms such as rootkit deployment and data exfiltration capabilities that operate below the operating system level. Security professionals should note that this vulnerability can be exploited for advanced persistent threat campaigns where traditional endpoint protection solutions provide no defense against firmware-level attacks.
Mitigation strategies should focus on immediate firmware updates from Insyde and system administrators should implement strict firmware update policies with cryptographic verification. Organizations should also deploy firmware integrity monitoring solutions and consider implementing hardware security modules to protect against unauthorized certificate modifications. The vulnerability highlights the importance of maintaining secure boot chains and proper certificate management within embedded systems. Regular firmware audits and vulnerability assessments should be conducted to identify similar weaknesses in other firmware implementations. Additionally, system administrators should implement network segmentation and monitoring to detect anomalous EFI execution patterns that may indicate exploitation attempts. The remediation process requires careful coordination with hardware vendors and may involve complete system replacement in some cases to ensure complete removal of the malicious certificate modifications.