A major vulnerability, CVE-2023-4512, has been discovered in Wireshark versions 4.. to 4..6, which could potentially lead to a denial of service (DoS) attack. Wireshark is a widely-used network protocol analyzer that allows users to troubleshoot network issues and analyze network traffic. This vulnerability enables an attacker to crash Wireshark's CBOR dissector, leading to a denial of service through packet injection or a crafted capture file.

In this in-depth analysis, we will explore the details of this vulnerability, its impact, the vulnerable code snippet, published references, and potential exploit solutions.

Exploit Details

The vulnerability CVE-2023-4512 affects the CBOR (Concise Binary Object Representation) dissector in Wireshark. The CBOR dissector is responsible for parsing and displaying CBOR data – a binary data serialization format often used in constrained environments like IoT (Internet of Things) devices.

The exploitation of the vulnerability allows an attacker to cause the CBOR dissector to crash. As a result, Wireshark is unable to properly parse and analyze network packets, leading to a denial of service (DoS) attack. This can be done by injecting malicious packets into the network or crafting a capture file containing malformed CBOR data to trigger the crash.

Vulnerable Code Snippet

To provide more insight into the vulnerability, here's a code snippet from Wireshark's CBOR dissector:

// cbor.c: CBOR dissector implementation
static int dissect_cbor(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data)
{
  [...]

  while (tvb_reported_length_remaining(tvb, offset) > )
  {
    guint64 start_offset = offset;

    // Decode the CBOR item
    cbor_error_t res = cbor_decode_item(tvb, &offset, pinfo);

    if (res != CBOR_OK)  // If there is an error when decoding, then break the loop
    {
      break;
    }
    [...]
  }

  [...]
}

The dissect_cbor() function is responsible for iterating over the CBOR items in the provided tvbuff_t buffer. A vulnerability occurs if there is a logical error within the cbor_decode_item() function, causing an infinite loop that results in the crash of the CBOR dissector.

Original References

1. Wireshark Security Advisory
2. CVE-2023-4512 Record on the National Vulnerability Database

Potential Exploit Solutions

To mitigate this vulnerability and protect your Wireshark application from a potential DoS attack, we recommend the following steps:

1. Upgrade Wireshark to the latest stable version (4..7 or higher): The Wireshark development team has addressed the vulnerability by fixing the CBOR dissector in version 4..7. Updating your Wireshark installation to this version or a later release will ensure you won't be susceptible to this type of attack.

2. Disable the CBOR dissector: If you cannot upgrade your Wireshark installation at the moment, you can temporarily disable the CBOR dissector in Wireshark by navigating to "Analyze" -> "Enabled Protocols" -> untick "CBOR".

3. Triage network traffic from untrusted sources: Be cautious when analyzing network traffic or capture files originating from untrusted sources. Always check the provenance of any files or data you're working with to avoid potential exploitation attempts.

Conclusion

By thoroughly understanding the CVE-2023-4512 vulnerability in Wireshark and taking appropriate steps to address it, you can better protect your network analysis environment from potential denial of service attacks. Remain vigilant, continue to monitor security advisories, and upgrade your Wireshark installation as needed to stay one step ahead of potential threats.

Timeline

Published on: 08/24/2023 07:15:00 UTC
Last modified on: 09/15/2023 22:15:00 UTC