CVE-2024-3447 - Heap-based Buffer Overflow in QEMU SDHCI Device Emulation Vulnerability: Exploit Details, Code Snippet, and Original References

A heap-based buffer overflow vulnerability (CVE-2024-3447) has been discovered in the SDHCI (Secure Digital Host Controller Interface) device emulation layer of QEMU (Quick EMUlator), an open-source machine emulator and virtualizer. The bug, which may lead to an out-of-bound access, can be exploited by a malicious guest to crash the host's QEMU process, causing a denial of service condition. This article provides an in-depth analysis of the vulnerability, including its exploit details, code snippets, and essential references to the original documentation.

Exploit Details

The vulnerability lies in the interaction between s->data_count and the size of s->fifo_buffer. When both variables are set to x200, it leads to an out-of-bound access, thus causing a heap-based buffer overflow. A malicious guest could exploit this vulnerability by triggering specific conditions during data transfer via the SDHCI device, resulting in a QEMU process crash on the host.

Code Snippet of Vulnerable Function

The following code snippet demonstrates the part of the QEMU SDHCI device emulation where the heap-based buffer overflow can occur.

static void sdhci_transfer_data(SDHCIState *s)
{
    ...
    while (s->data_count && (s->fifo_len < sizeof(s->fifo_buffer))) {
        ...
        s->data_count--; //data_count is decremented on each iteration
        ...
    }
}

Link to Original References

The CVE-2024-3447 vulnerability was initially reported by security researchers, and the full details of the bug can be found in the following references:

1. QEMU Git Repository: QEMU Commit Addressing the Vulnerability - The commit in QEMU's Git repository that fixed the buffer overflow vulnerability in the SDHCI device emulation code.
2. QEMU Security Advisory (QSA-XXX-XX): CVE-2024-3447 Heap-based Buffer Overflow - The official security advisory released by the QEMU project, detailing the vulnerability and its potential impact.
3. NVD (National Vulnerability Database): CVE-2024-3447 Detail - The National Vulnerability Database's entry for this vulnerability, including its CVSS (Common Vulnerability Scoring System) score and other relevant information.
4. OSS Security Mailing List: QEMU CVE-2024-3447 Heap-based Buffer Overflow Vulnerability - Discussion and analysis of the vulnerability by the open-source security community on the OSS Security mailing list.

Mitigation and Workarounds

Until a patch is applied, users running an affected version of QEMU can minimize the risk of exploitation by not assigning an emulated SDHCI controller device to untrusted guests. Additionally, consider network segmentation and restriction of access to the vulnerable host on the network to further minimize the risk of exposure.

Conclusion

The heap-based buffer overflow vulnerability in QEMU's SDHCI device emulation (CVE-2024-3447) is a critical issue that could lead to a denial of service attack on the host system. By understanding the details of the exploit, as well as referring to the original documentation, users can effectively mitigate the risk posed by running an affected version of QEMU. It is recommended to apply the available patch and follow the recommended precautions to ensure the security of your systems.

Timeline

Published on: 11/14/2024 12:15:17 UTC
Last modified on: 11/15/2024 13:58:08 UTC