CVE-2018-3954 : Exploit Details and Defense Strategies

The Linksys ESeries routers, specifically E1200 Firmware Version 2.0.09 and E2500 Firmware Version 3.0.04, are vulnerable to OS command injection due to inadequate data filtering in NVRAM.

Understanding CVE-2018-3954

This CVE involves a security vulnerability in Linksys ESeries routers that can be exploited through the 'Router Name' input field on the web portal.

What is CVE-2018-3954?

The vulnerability allows attackers to inject OS commands by manipulating the 'machine_name' POST parameter, potentially leading to unauthorized access and control of the affected routers.

The Impact of CVE-2018-3954

CVSS Base Score: 7.2 (High Severity)
Attack Vector: Network
Attack Complexity: Low
Privileges Required: High
Confidentiality, Integrity, and Availability Impact: High

Technical Details of CVE-2018-3954

The following technical details outline the vulnerability and its implications.

Vulnerability Description

The vulnerability arises from insufficient data filtering in NVRAM, allowing malicious injection of OS commands via the 'Router Name' input field.

Affected Systems and Versions

Linksys ESeries E1200 Firmware Version 2.0.09
Linksys ESeries E2500 Firmware Version 3.0.04

Exploitation Mechanism

Attackers manipulate the 'machine_name' POST parameter to execute unauthorized OS commands.
The 'preinit' binary triggers the vulnerability by calling the 'set_host_domain_name' function.

Mitigation and Prevention

Protect your systems from CVE-2018-3954 with the following measures.

Immediate Steps to Take

Update affected routers to the latest firmware version.
Monitor network traffic for any suspicious activity.
Restrict access to the router's web portal.

Long-Term Security Practices

Regularly audit and update router configurations.
Implement strong password policies and multi-factor authentication.
Conduct security training for network administrators.

Patching and Updates

Check for firmware updates from Linksys and apply them promptly to address the vulnerability.