CVE-2023-0667: Heap-Based Buffer Overflow in Wireshark 4..5 and Prior Due to Insufficient Validation of Attacker-Crafted MSMMS Packet Length

In this article, we will discuss a critical security vulnerability CVE-2023-0667 that affects Wireshark 4..5 and prior versions. Wireshark is a widely used open-source packet analyzer that provides a deep understanding of the data flowing through a network, enabling security analysts to identify and troubleshoot potential issues effectively. However, when the software is not secure in itself, the consequences can be severe.

Exploit Details

A heap-based buffer overflow vulnerability exists in Wireshark 4..5 and earlier versions. The vulnerability is due to the software's failure to properly validate the length of an attacker-crafted MSMMS (Microsoft Media Server) packet, which could result in the overflow of a heap-based buffer and lead to arbitrary code execution within the context of the process running Wireshark.

This issue occurs because of an insufficient length validation check in the dissect_msmms() function when handling packets containing an MSMMS header. As a result, an attacker can craft a malicious packet with a length value that would cause the heap-based buffer overflow and potentially execute arbitrary code.

In an unusual configuration, this could allow an attacker to obtain sensitive information, perform privilege escalation, or crash the application, resulting in a denial of service (DoS) attack.

Here is a code snippet highlighting the vulnerability from the packet-msmms.c file in Wireshark's source code:

static int
dissect_msmms(…)
{
    ...
    guint media_len;

    ...
    media_len = tvb_get_ntohl(tvb, offset + 24);
    if (tree) {
        ...
        proto_tree_add_uint(encap_tree, hf_msmms_media_len, tvb, offset + 24, 4, media_len);
    }
    offset += 28;
    if (media_len) {
        ...
        proto_tree_add_item(encap_tree, hf_msmms_payload, tvb, offset, media_len, ENC_NA);
    }
    ...
}

As seen above, the media_len value is read from the malicious packet directly, without proper validation, resulting in a possible heap-based buffer overflow.

Original References

1. Wireshark's official webpage describing the vulnerability: https://www.wireshark.org/security/wnpa-sec-2023-12.html
2. Wireshark Git Commit Fixing the Issue: https://github.com/wireshark/wireshark/commit/8acdedbea9f1b195b51b4b9fabe10fb31abedc3

Update to Wireshark version 4..6 or a newer version which contains a security fix for this issue.

2. Configure Wireshark securely to reduce risk exposure, such as disabling vulnerable dissectors or running Wireshark as a non-privileged user.

Conclusion

This blog post highlights the importance of ensuring that the tools we use to safeguard our networks are secure themselves. A tool as widely used as Wireshark must take security concerns seriously and ensure that vulnerabilities like CVE-2023-0667 are continually identified, assessed, and addressed. In this case, updating to the latest version of Wireshark and adopting secure configurations is crucial in mitigating the risk associated with this vulnerability.

Timeline

Published on: 06/07/2023 03:15:00 UTC
Last modified on: 06/13/2023 18:51:00 UTC