CVE-2024-57255 in U-Boot
Summary
by MITRE • 02/19/2025
An integer overflow in sqfs_resolve_symlink in Das U-Boot before 2025.01-rc1 occurs via a crafted squashfs filesystem with an inode size of 0xffffffff, resulting in a malloc of zero and resultant memory overwrite.
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Analysis
by VulDB Data Team • 06/01/2025
The vulnerability CVE-2024-57255 represents a critical integer overflow flaw within Das U-Boot's squashfs filesystem handling mechanism. This issue specifically affects the sqfs_resolve_symlink function which processes symbolic links within squashfs filesystems. The vulnerability manifests when a maliciously crafted squashfs filesystem contains an inode size value of 0xffffffff, which translates to the maximum unsigned 32-bit integer value. This particular value triggers a cascading failure in the memory allocation process that ultimately leads to a dangerous memory overwrite condition.
The technical implementation of this vulnerability stems from improper input validation within the squashfs parsing routines of Das U-Boot. When the system encounters an inode size of 0xffffffff, the integer overflow occurs during the calculation or processing of this value, causing the malloc function to receive a parameter of zero bytes. This zero-sized allocation creates a memory overwrite scenario where subsequent operations may write data to memory locations that were not properly allocated, potentially leading to arbitrary code execution or system instability. The vulnerability is classified under CWE-190 as an integer overflow condition, specifically involving an unsigned integer that is incremented beyond its maximum value.
The operational impact of this vulnerability extends significantly within embedded systems that rely on Das U-Boot for their boot process and system initialization. Attackers can exploit this condition by preparing a malicious squashfs filesystem and presenting it to a vulnerable system during the boot process or while mounting filesystems. The memory overwrite can potentially corrupt critical data structures, overwrite function pointers, or manipulate control flow within the bootloader, leading to complete system compromise. This vulnerability particularly affects systems that support squashfs filesystems as part of their storage or update mechanisms, including IoT devices, embedded routers, and industrial control systems that utilize Das U-Boot as their primary bootloader.
Mitigation strategies for CVE-2024-57255 require immediate deployment of Das U-Boot version 2025.01-rc1 or later, which includes patches that properly validate inode size values and prevent the integer overflow condition. System administrators should also implement strict filesystem validation procedures for any squashfs images used in production environments, particularly those that may be sourced from untrusted parties. Additional protective measures include monitoring for unusual memory allocation patterns and implementing memory protection mechanisms such as stack canaries and address space layout randomization. From an ATT&CK framework perspective, this vulnerability aligns with techniques involving privilege escalation and execution through boot or installation processes, specifically targeting the bootkit category where adversaries seek to compromise systems during early boot phases. Organizations should also consider implementing firmware integrity checking mechanisms and regular security assessments of their embedded systems to prevent exploitation of similar vulnerabilities in the bootloader stack.