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MediumCISA KEVExploited in the wildPublic exploit

IGEL OS Boot Signature Verification Bypass

IdentifiersCVE-2025-47827CWE-347· Improper Verification of…

CVE-2025-47827 is a Secure Boot bypass in IGEL OS versions before 11. The flaw is caused by improper cryptographic signature verification in the igel-flash-driver kernel module. Because the module does not correctly validate the signature protecting the booted filesystem image, an attacker can supply a crafted SquashFS image and have an unverified root filesystem mounted during boot. This breaks the intended Secure Boot chain of trust on affected devices. Public reporting and the associated proof-of-concept indicate the issue can be leveraged to boot with an attacker-controlled root filesystem and, from that trusted boot context, load or transition to an untrusted kernel, including via kexec, defeating platform boot integrity guarantees.

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ANALYST BRIEF

Impact, mitigation & remediation

What it means. What to do now. Patch path, mitigations, and the assume-compromise checklist.

Impact

What an attacker gets, and what they’ve been doing with it.

Successful exploitation allows bypass of Secure Boot protections on affected IGEL OS devices, enabling boot of an attacker-controlled, unverified root filesystem. This can provide persistent root-level compromise of the endpoint, including the ability to run an untrusted kernel, install boot- or kernel-level malware/rootkits, tamper with sessions, steal credentials, and undermine the integrity of thin-client or VDI environments. In enterprise deployments, compromise of these endpoints can facilitate lateral movement and abuse of access to hosted desktop environments.

Mitigation

If you can’t patch tonight, do this now.

If immediate upgrade is not possible, reduce exposure by treating affected IGEL OS 10 devices as high risk, restricting physical and boot-media access, disabling unauthorized USB/removable boot paths, enforcing firmware passwords and UEFI boot protections, and using device-management policy to prevent boot configuration changes. Monitor for unexpected boot entry changes, UEFI variable modifications, anomalous SquashFS mounts during initramfs, non-standard boot artifacts, and kexec usage. Where operationally appropriate, apply relevant Secure Boot DBX revocation updates after staged testing and recovery planning, as revocations may be disruptive.

Remediation

Patch, then assume compromise.

Upgrade affected systems to a fixed IGEL OS release. The provided content states IGEL OS 11 and 12 are not affected and that IGEL patched the issue in version 11; example fixed versions cited in the source material include IGEL OS 11.10.410 or later and IGEL OS 12.7.0 or later. IGEL guidance recommends upgrading legacy IGEL OS 10 deployments rather than expecting backported fixes to unsupported releases. Systems that cannot be upgraded should be retired or isolated.
PUBLIC EXPLOITS

Exploits

1 valid exploit after Mallory filtered fakes, detection scripts, and README-only repos.

VALID 1 / 1 TOTALView more in app
CVE-2025-47827MaturityPoCVerified exploit

This repository provides a proof-of-concept (PoC) exploit for CVE-2025-47827, a Secure Boot bypass vulnerability in IGEL OS 10 (before v11). The vulnerability arises from improper cryptographic signature verification in the igel-flash-driver kernel module, allowing an attacker to boot a malicious root filesystem from an unverified SquashFS image. The exploit leverages the kexec syscall to replace the running kernel with an attacker-controlled one, either fetched over HTTP or from local disk, thus bypassing Secure Boot and enabling arbitrary code execution at the kernel level. The repository contains several key files: - `mkdiskimage`: A Bash script that automates the process of downloading the official IGEL UDC3 image, extracting and patching the system image, and assembling a bootable disk image with a custom root filesystem or kernel. - `root/sbin/init`: A shell script used as the init process, which parses kernel command-line arguments, fetches or mounts the specified kernel and initrd (supporting both HTTP and local sources), and uses kexec to boot into the attacker-supplied kernel. - `esp/boot/grub/igel.conf`: A GRUB configuration file that defines menu entries for both network and local kexec booting, specifying parameters for kernel, initrd, and command-line arguments. The exploit is primarily local (requires physical or privileged access to the device to modify the boot process), but it also supports network-based payload delivery (fetching kernel/initrd over HTTP). The PoC demonstrates how an attacker can persistently compromise a device by replacing its kernel, effectively rendering Secure Boot protections ineffective on affected IGEL OS systems. The README provides extensive documentation, impact analysis, and references to related resources.

ZedeldiDisclosed May 20, 2025bashshlocalnetwork
EXPOSURE SURFACE

Affected products & vendors

Products and vendors Mallory has correlated with this vulnerability. Open in Mallory to drill down to specific CPE configurations and version ranges.

VendorProductType
IgelIgel Osoperating_system
Microsoft CorporationWindows 10 1507operating_system
Microsoft CorporationWindows 10 1607operating_system
Microsoft CorporationWindows 10 1809operating_system
Microsoft CorporationWindows 10 21h2operating_system
Microsoft CorporationWindows 10 22h2operating_system
Microsoft CorporationWindows 11 22h2operating_system
Microsoft CorporationWindows 11 23h2operating_system
Microsoft CorporationWindows 11 24h2operating_system
Microsoft CorporationWindows 11 25h2operating_system
Microsoft CorporationWindows Server 2012operating_system
Microsoft CorporationWindows Server 2016operating_system
Microsoft CorporationWindows Server 2019operating_system
Microsoft CorporationWindows Server 2022operating_system
Microsoft CorporationWindows Server 2022 23h2operating_system
Microsoft CorporationWindows Server 2025operating_system

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Exposure mapping

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Threat actor evidence

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Associated malware

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Detection signatures1

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Vendor-by-vendor mapping

Cross-references every affected SKU, including bundled OEM variants.

Social activity22

Community discussion across Reddit, Mastodon, and other social sources.