CVE-2018-3969 : Exploit Details and Defense Strategies

A vulnerability has been discovered in the verified boot protection system of the CUJO Smart Firewall, allowing unauthorized access through the insertion of arbitrary shell commands into the dhcpd.conf file.

Understanding CVE-2018-3969

This CVE entry describes a critical security flaw in the CUJO Smart Firewall that could lead to the execution of unverified commands.

What is CVE-2018-3969?

The vulnerability in the CUJO Smart Firewall enables attackers to insert arbitrary shell commands into the dhcpd.conf file, granting unauthorized access and persistence even after reboots and firmware updates.

The Impact of CVE-2018-3969

The vulnerability poses a high risk with a CVSS base score of 8.2, affecting confidentiality, integrity, and availability due to the execution of unverified commands by attackers with local access.

Technical Details of CVE-2018-3969

This section provides detailed technical information about the vulnerability.

Vulnerability Description

The flaw allows the insertion of arbitrary shell commands into the dhcpd.conf file, leading to unauthorized access and execution of unverified commands.

Affected Systems and Versions

Product: CUJO
Version: CUJO Smart Firewall - Firmware version 7003

Exploitation Mechanism

Attackers with local access can write into the /config/dhcpd.conf directory, enabling them to exploit the vulnerability.

Mitigation and Prevention

Protect your systems from CVE-2018-3969 with the following steps:

Immediate Steps to Take

Monitor and restrict access to the /config/dhcpd.conf directory.
Implement strong access controls and permissions to prevent unauthorized modifications.
Regularly monitor for any suspicious activities or changes in the dhcpd.conf file.

Long-Term Security Practices

Conduct regular security audits and vulnerability assessments.
Keep firmware and software up to date to patch known vulnerabilities.
Educate users on best practices for securing network devices.

Patching and Updates

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