CVE-2019-11366 Explained : Impact and Mitigation

A vulnerability was found in the atftpd server in atftp version 0.7.1. The lack of proper locking of the thread_list_mutex mutex can lead to a denial of service attack by triggering a NULL pointer dereference.

Understanding CVE-2019-11366

This CVE identifies a vulnerability in the atftpd server in atftp version 0.7.1 that can be exploited by attackers to cause a denial of service.

What is CVE-2019-11366?

This vulnerability arises from the improper locking of the thread_list_mutex mutex before assigning the current thread data structure in atftpd server.

The Impact of CVE-2019-11366

The vulnerability allows attackers to trigger a NULL pointer dereference, leading to a denial of service attack on the affected system.

Technical Details of CVE-2019-11366

The technical details of the CVE-2019-11366 vulnerability are as follows:

Vulnerability Description

The issue lies in the lack of proper locking of the thread_list_mutex mutex before assigning the current thread data structure.
Exploiting this flaw can result in a denial of service attack by triggering a NULL pointer dereference.

Affected Systems and Versions

Product: atftp
Version: 0.7.1

Exploitation Mechanism

If the thread_data is assigned to current while being NULL and is modified by another thread before a certain tftpd_list.c check, the program crashes when attempting to access current->next.

Mitigation and Prevention

To address CVE-2019-11366, consider the following mitigation strategies:

Immediate Steps to Take

Update to a patched version of atftp to mitigate the vulnerability.
Monitor network traffic for any signs of exploitation.

Long-Term Security Practices

Implement proper mutex locking mechanisms in the code to prevent similar vulnerabilities.
Regularly update and patch software to address known security issues.

Patching and Updates

Apply the security updates provided by the vendor to fix the vulnerability in atftp version 0.7.1.