CVE-2020-24340 : What You Need to Know

An issue was discovered in picoTCP and picoTCP-NG through 1.7.0 that can lead to a Denial-of-Service due to a vulnerability in processing DNS responses.

Understanding CVE-2020-24340

This CVE identifies a flaw in picoTCP and picoTCP-NG versions up to 1.7.0 that can result in out-of-bounds read and invalid pointer dereference.

What is CVE-2020-24340?

The vulnerability lies in the code processing DNS responses in pico_mdns_handle_data_as_answers_generic() in pico_mdns.c. It fails to validate if the number of answers/responses in a DNS packet header matches the response data, allowing for potential exploitation.

The Impact of CVE-2020-24340

The vulnerability can be exploited to trigger an out-of-bounds read, invalid pointer dereference, and ultimately a Denial-of-Service condition, affecting the availability of the system.

Technical Details of CVE-2020-24340

This section delves into the specifics of the vulnerability.

Vulnerability Description

The issue arises from the lack of validation in processing DNS responses, enabling attackers to cause a DoS by manipulating response data.

Affected Systems and Versions

picoTCP and picoTCP-NG versions up to 1.7.0 are impacted.

Exploitation Mechanism

Attackers can exploit this vulnerability by crafting malicious DNS responses with inconsistent data, leading to out-of-bounds reads and invalid pointer dereferences.

Mitigation and Prevention

Protecting systems from CVE-2020-24340 requires immediate actions and long-term security measures.

Immediate Steps to Take

Implement network-level protections to filter out potentially malicious DNS responses.
Monitor DNS traffic for anomalies that could indicate exploitation attempts.

Long-Term Security Practices

Regularly update picoTCP and picoTCP-NG to patched versions that address this vulnerability.
Conduct security assessments to identify and remediate similar issues in the network infrastructure.

Patching and Updates

Apply patches provided by the software vendor to fix the vulnerability and prevent exploitation.