CVE-2017-3731 Explained : Impact and Mitigation

In the event that a 32-bit host is operating an SSL/TLS server or client, and a particular cipher is employed, the utilization of a truncated packet may lead to the occurrence of an out-of-bounds read, resulting in a crash. Upgrading to version 1.1.0d of OpenSSL is recommended for users experiencing this issue with the CHACHA20/POLY1305 cipher. Similarly, users utilizing OpenSSL 1.0.2 and encountering the crash with the RC4-MD5 cipher are advised to update to version 1.0.2k if they have not disabled this algorithm.

Understanding CVE-2017-3731

This CVE involves a vulnerability in OpenSSL that could result in a crash due to an out-of-bounds read when a truncated packet is processed.

What is CVE-2017-3731?

CVE-2017-3731 is a security vulnerability in OpenSSL that affects SSL/TLS servers or clients running on 32-bit hosts using specific ciphers, potentially leading to crashes.

The Impact of CVE-2017-3731

The vulnerability could allow attackers to trigger crashes in SSL/TLS servers or clients, impacting the availability and stability of affected systems.

Technical Details of CVE-2017-3731

This section provides more technical insights into the vulnerability.

Vulnerability Description

The vulnerability arises when a 32-bit host running an SSL/TLS server or client encounters a truncated packet, causing an out-of-bounds read and potentially leading to a crash.

Affected Systems and Versions

OpenSSL versions affected include 1.1.0, 1.0.2, and their subsequent releases up to specific versions.

Exploitation Mechanism

The vulnerability can be exploited by sending a truncated packet to an SSL/TLS server or client using certain ciphers, triggering the out-of-bounds read and subsequent crash.

Mitigation and Prevention

To address CVE-2017-3731, users should take immediate steps and implement long-term security practices.

Immediate Steps to Take

Upgrade OpenSSL to version 1.1.0d if using the CHACHA20/POLY1305 cipher and experiencing issues.
Update to OpenSSL version 1.0.2k if encountering crashes with the RC4-MD5 cipher.

Long-Term Security Practices

Regularly monitor for security advisories and updates from OpenSSL.
Disable vulnerable ciphers and algorithms to mitigate risks.

Patching and Updates

Apply patches and updates provided by OpenSSL to address the vulnerability and enhance system security.