CVE-2019-16239 : Exploit Details and Defense Strategies

OpenConnect before version 8.05 is vulnerable to a Buffer Overflow issue due to improper handling of HTTP chunked encoding. Malicious servers can exploit this vulnerability by using manipulated chunk sizes.

Understanding CVE-2019-16239

OpenConnect, a VPN client, is susceptible to a Buffer Overflow vulnerability when processing HTTP responses with crafted chunk sizes.

What is CVE-2019-16239?

The vulnerability in OpenConnect arises when a malicious server sends HTTP responses with manipulated chunk sizes, leading to a Buffer Overflow.

The Impact of CVE-2019-16239

This vulnerability could allow a remote attacker to execute arbitrary code or cause a denial of service (DoS) condition on the affected system.

Technical Details of CVE-2019-16239

OpenConnect's vulnerability can be further understood through technical details.

Vulnerability Description

The 'process_http_response' function in OpenConnect versions prior to 8.05 is prone to a Buffer Overflow when handling HTTP chunked encoding with manipulated chunk sizes.

Affected Systems and Versions

Product: OpenConnect
Vendor: N/A
Versions Affected: All versions before 8.05

Exploitation Mechanism

Malicious servers can exploit this vulnerability by sending HTTP responses with crafted chunk sizes, triggering the Buffer Overflow in OpenConnect.

Mitigation and Prevention

Protecting systems from CVE-2019-16239 requires immediate actions and long-term security practices.

Immediate Steps to Take

Update OpenConnect to version 8.05 or newer to mitigate the vulnerability.
Monitor vendor advisories and security mailing lists for patches and updates.

Long-Term Security Practices

Regularly update software and apply security patches promptly.
Implement network segmentation and access controls to limit exposure to potential threats.
Conduct regular security assessments and penetration testing to identify and address vulnerabilities.

Patching and Updates

Apply patches provided by OpenConnect promptly to address the Buffer Overflow vulnerability.
Stay informed about security updates and advisories from relevant vendors and security communities.