CVE-2020-7461 Explained : Impact and Mitigation
Learn about CVE-2020-7461, a heap overflow vulnerability in FreeBSD's dhclient(8) service, potentially allowing remote code execution. Find mitigation steps and preventive measures here.
In FreeBSD 12.1-STABLE before r365010, 11.4-STABLE before r365011, 12.1-RELEASE before p9, 11.4-RELEASE before p3, and 11.3-RELEASE before p13, a vulnerability in dhclient(8) could lead to a heap overflow, potentially allowing remote code execution.
Understanding CVE-2020-7461
This CVE involves a heap-based buffer overflow vulnerability in FreeBSD's dhclient(8) service.
What is CVE-2020-7461?
The vulnerability in dhclient(8) in FreeBSD versions mentioned allows handling of certain malformed input related to DHCP option 119 incorrectly, resulting in a heap overflow. This overflow could potentially be exploited to achieve remote code execution.
The Impact of CVE-2020-7461
The affected process operates with reduced privileges in a Capsicum sandbox, which limits the immediate impact of an exploit. However, successful exploitation could lead to remote code execution.
Technical Details of CVE-2020-7461
This section provides more technical insights into the vulnerability.
Vulnerability Description
The vulnerability is a heap-based buffer overflow in dhclient(8) in specific FreeBSD versions, potentially allowing remote code execution.
Affected Systems and Versions
- FreeBSD 12.1-RELEASE before p9
- FreeBSD 11.4-RELEASE before p3
- FreeBSD 11.3-RELEASE before p13
Exploitation Mechanism
The vulnerability arises from mishandling of certain malformed input related to DHCP option 119, leading to a heap overflow that could be exploited for remote code execution.
Mitigation and Prevention
Protecting systems from CVE-2020-7461 requires immediate actions and long-term security practices.
Immediate Steps to Take
- Apply the necessary patches provided by FreeBSD promptly.
- Monitor security advisories for updates and follow best practices for secure network configurations.
Long-Term Security Practices
- Regularly update and patch FreeBSD systems to mitigate known vulnerabilities.
- Implement network segmentation and access controls to limit the impact of potential exploits.
- Conduct regular security audits and penetration testing to identify and address security weaknesses.
Patching and Updates
Ensure that FreeBSD systems are updated with the latest patches and security fixes to address the vulnerability effectively.