CVE-2025-47827 Overview
CVE-2025-47827 is a Secure Boot bypass vulnerability affecting IGEL OS before version 11. The vulnerability exists in the igel-flash-driver module, which improperly verifies cryptographic signatures. This flaw allows an attacker with physical access to mount a crafted root filesystem from an unverified SquashFS image, effectively bypassing the Secure Boot chain of trust.
Critical Impact
This vulnerability allows attackers with physical access to bypass Secure Boot protections and execute arbitrary code by mounting malicious root filesystems. CISA has added this vulnerability to its Known Exploited Vulnerabilities catalog, indicating active exploitation in the wild.
Affected Products
- IGEL OS (versions prior to 11)
- Microsoft Windows 10 (versions 1507, 1607, 1809, 21H2, 22H2)
- Microsoft Windows 11 (versions 22H2, 23H2, 24H2, 25H2)
- Microsoft Windows Server 2012, 2016, 2019, 2022, 2022 23H2, 2025
Discovery Timeline
- 2025-06-05 - CVE-2025-47827 published to NVD
- 2025-11-05 - Last updated in NVD database
Technical Details for CVE-2025-47827
Vulnerability Analysis
This vulnerability represents a critical flaw in the Secure Boot implementation of IGEL OS. The igel-flash-driver kernel module fails to properly verify cryptographic signatures when loading filesystem images. The improper verification (CWE-347) allows an attacker to craft a malicious SquashFS image that bypasses signature validation checks, ultimately enabling the mounting of an unverified root filesystem.
The attack requires physical access to the target device, which limits remote exploitation but makes it particularly dangerous in scenarios involving stolen devices, insider threats, or supply chain attacks. Once the Secure Boot chain is compromised, an attacker can execute arbitrary code with kernel-level privileges, undermining the entire security posture of the system.
Microsoft has also issued updates related to this vulnerability, indicating that the vulnerable IGEL driver may interact with Windows systems in dual-boot or virtualization scenarios, broadening the potential attack surface.
Root Cause
The root cause is improper verification of cryptographic signatures (CWE-347) in the igel-flash-driver module. The signature validation routine contains a flaw that allows specially crafted filesystem images to pass verification checks despite not having valid signatures. This breaks the chain of trust that Secure Boot is designed to establish between the firmware and the operating system.
Attack Vector
The attack vector is physical, requiring an attacker to have direct access to the target device. The exploitation process involves:
- Creating a malicious SquashFS image containing a crafted root filesystem
- Manipulating the signature verification process exploited by the igel-flash-driver module
- Booting the device with the crafted image, bypassing Secure Boot protections
- Achieving arbitrary code execution with elevated privileges
The vulnerability has been documented with proof-of-concept code available in the GitHub PoC Repository. Additional technical details and tooling related to the IGEL filesystem can be found in the igelfs project repository.
Detection Methods for CVE-2025-47827
Indicators of Compromise
- Unexpected modifications to boot configuration or Secure Boot settings
- Presence of unsigned or improperly signed SquashFS images on boot media
- Evidence of physical tampering with device storage or boot partitions
- Anomalous kernel module loading behavior related to igel-flash-driver
Detection Strategies
- Monitor Secure Boot event logs for signature verification failures or bypasses
- Implement file integrity monitoring on boot partitions and firmware images
- Deploy endpoint detection solutions capable of identifying boot-level tampering
- Audit physical access to devices running IGEL OS
Monitoring Recommendations
- Enable and centralize Secure Boot audit logging across affected endpoints
- Configure alerts for changes to boot configuration or kernel module loading
- Implement hardware security module (HSM) attestation where available
- Review UEFI/BIOS logs for anomalous boot sequences
How to Mitigate CVE-2025-47827
Immediate Actions Required
- Update IGEL OS to version 11 or later immediately
- Apply the latest Windows security updates from Microsoft addressing this vulnerability
- Restrict physical access to affected devices
- Enable UEFI Secure Boot with verified signing keys and revoke compromised keys
Patch Information
IGEL has addressed this vulnerability in IGEL OS version 11 and later. Organizations should prioritize updating to patched versions. Microsoft has also released updates for affected Windows versions; refer to the Microsoft Security Update Guide for platform-specific patch information.
This vulnerability is listed in the CISA Known Exploited Vulnerabilities Catalog, mandating federal agencies to apply patches by the specified deadline.
Workarounds
- Implement physical security controls to prevent unauthorized device access
- Enable BitLocker or equivalent full-disk encryption with TPM and PIN requirements
- Configure UEFI firmware passwords to prevent boot configuration changes
- Consider disabling external boot media until patches can be applied
- Deploy endpoint protection solutions with boot integrity verification capabilities
# Example: Verify IGEL OS version and Secure Boot status
# Check IGEL OS version
cat /etc/igel-release
# Verify Secure Boot is enabled (Linux)
mokutil --sb-state
# Review boot configuration integrity
bootctl status
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
