CVE-2019-5597 : Vulnerability Insights and Analysis

A vulnerability has been found in FreeBSD versions 11.3-PRERELEASE and 12.0-STABLE prior to r347591, 11.2-RELEASE prior to 11.2-RELEASE-p10, and 12.0-RELEASE prior to 12.0-RELEASE-p4. This vulnerability arises from a bug in the pf IPv6 fragment reassembly logic, potentially allowing harmful IPv6 packets to cause system crashes or bypass packet filters due to incorrect header offset usage.

Understanding CVE-2019-5597

This CVE identifies a vulnerability in FreeBSD versions that could be exploited by specially crafted IPv6 packets.

What is CVE-2019-5597?

In FreeBSD versions 11.3-PRERELEASE and 12.0-STABLE before r347591, 11.2-RELEASE before 11.2-RELEASE-p10, and 12.0-RELEASE before 12.0-RELEASE-p4, a bug in the pf IPv6 fragment reassembly logic incorrectly uses the last extension header offset from the last received packet instead of the first packet, potentially leading to system crashes or packet filter bypasses.

The Impact of CVE-2019-5597

The vulnerability allows maliciously crafted IPv6 packets to exploit the bug in the pf IPv6 fragment reassembly logic, potentially causing system crashes or bypassing packet filters.

Technical Details of CVE-2019-5597

This section provides detailed technical information about the CVE.

Vulnerability Description

The vulnerability in FreeBSD versions arises from incorrect usage of the last extension header offset from the last received packet instead of the first packet, enabling malicious IPv6 packets to disrupt system operations.

Affected Systems and Versions

Affected versions include FreeBSD 11.3-PRERELEASE, 12.0-STABLE before r347591, 11.2-RELEASE before 11.2-RELEASE-p10, and 12.0-RELEASE before 12.0-RELEASE-p4.

Exploitation Mechanism

Attackers can exploit this vulnerability by sending specially crafted IPv6 packets to trigger system crashes or bypass packet filters.

Mitigation and Prevention

Protecting systems from CVE-2019-5597 requires immediate actions and long-term security practices.

Immediate Steps to Take

Apply the recommended patches provided by FreeBSD to address the vulnerability.
Monitor network traffic for any signs of exploitation.

Long-Term Security Practices

Regularly update FreeBSD systems to the latest versions to mitigate known vulnerabilities.
Implement network intrusion detection systems to identify and block malicious traffic.

Patching and Updates

Stay informed about security advisories from FreeBSD and promptly apply patches to secure systems against potential threats.