CVE-2019-11873 : Security Advisory and Response

A Buffer Overflow vulnerability in wolfSSL 4.0.0 allows remote code execution by sending a crafted hello client packet to a TLSv1.3 wolfSSL server.

Understanding CVE-2019-11873

This CVE involves a specific vulnerability in the wolfSSL library that can be exploited by malicious actors to execute remote code on a server.

What is CVE-2019-11873?

The Buffer Overflow vulnerability in wolfSSL 4.0.0 occurs in the DoPreSharedKeys function in the tls13.c file when the size of the current identity exceeds the size of the client identity. By sending a specially crafted hello client packet to a TLSv1.3 wolfSSL server, an attacker can exploit this vulnerability.

The Impact of CVE-2019-11873

This vulnerability potentially enables an attacker to execute remote code on the server by manipulating the length fields of the packet and storing attack data in the server's memory.

Technical Details of CVE-2019-11873

wolfSSL 4.0.0 is susceptible to a Buffer Overflow vulnerability in the DoPreSharedKeys function in the tls13.c file.

Vulnerability Description

The DoPreSharedKeys function is vulnerable when the size of the current identity is larger than the client identity, allowing an attacker to send a specially crafted hello client packet to exploit the server.

Affected Systems and Versions

Affected Product: wolfSSL 4.0.0
Affected Vendor: N/A
Affected Versions: N/A

Exploitation Mechanism

Attacker sends a hello client packet with manipulated length fields over the network to a wolfSSL server
Length fields set to maximum value, causing buffer overflow
Attack data stored in server's memory, potentially enabling remote code execution

Mitigation and Prevention

Taking immediate steps and implementing long-term security practices are crucial to mitigate the risks associated with CVE-2019-11873.

Immediate Steps to Take

Apply vendor patches or updates promptly
Monitor network traffic for any suspicious activity
Implement network segmentation to limit the impact of potential attacks

Long-Term Security Practices

Regularly update and patch software to address known vulnerabilities
Conduct security assessments and penetration testing to identify and remediate weaknesses
Educate staff on cybersecurity best practices to enhance overall security posture

Patching and Updates

Check for security advisories from wolfSSL and apply recommended patches
Stay informed about security updates and best practices to protect against similar vulnerabilities