CVE-2024-57254
📋 TL;DR
An integer overflow vulnerability in Das U-Boot's squashfs filesystem parser allows attackers to cause memory corruption via specially crafted symlink entries. This affects systems using U-Boot bootloader with squashfs support, potentially leading to denial of service or arbitrary code execution during boot. Embedded devices, routers, and IoT devices using vulnerable U-Boot versions are primarily affected.
💻 Affected Systems
- Das U-Boot bootloader
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Remote attacker could achieve arbitrary code execution during boot process, potentially compromising the entire system before OS loads, leading to persistent compromise or bricking of device.
Likely Case
Local attacker with filesystem access could cause boot failure or denial of service by triggering the overflow during boot sequence.
If Mitigated
With proper access controls and signed boot components, impact limited to denial of service during boot requiring physical recovery.
🎯 Exploit Status
Requires ability to place crafted squashfs filesystem in boot path. Exploitation depends on memory layout and platform specifics.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 2025.01-rc1 and later
Vendor Advisory: https://source.denx.de/u-boot/u-boot/-/commit/c8e929e5758999933f9e905049ef2bf3fe6b140d
Restart Required: No
Instructions:
1. Update U-Boot source to 2025.01-rc1 or later. 2. Rebuild U-Boot with your device configuration. 3. Flash updated bootloader to device. 4. Verify boot process completes successfully.
🔧 Temporary Workarounds
Disable squashfs support
allRemove squashfs filesystem support from U-Boot configuration if not required for boot process.
# In U-Boot configuration: CONFIG_FS_SQUASHFS=n
Secure boot media
allImplement write protection for boot partitions and verify integrity of squashfs images before boot.
🧯 If You Can't Patch
- Implement secure boot with verified boot images to prevent unauthorized squashfs filesystems
- Restrict physical and logical access to boot media and configuration interfaces
🔍 How to Verify
Check if Vulnerable:
Check U-Boot version string during boot or via 'version' command in U-Boot console. If version is before 2025.01-rc1 and CONFIG_FS_SQUASHFS is enabled, system is vulnerable.Check Version:
In U-Boot console: versionVerify Fix Applied:
Verify U-Boot version is 2025.01-rc1 or later and test booting with a squashfs filesystem containing symlinks.📡 Detection & Monitoring
Log Indicators:
- U-Boot boot failures when mounting squashfs partitions
- Kernel panic during early boot phase
Network Indicators:
- None - this is a local bootloader vulnerability
SIEM Query:
Search for: 'U-Boot panic', 'squashfs error', or boot failure events in system logs