CVE-2018-3955 : What You Need to Know

A vulnerability has been discovered in the Linksys ESeries line of routers, specifically affecting the Linksys E1200 Firmware Version 2.0.09 and Linksys E2500 Firmware Version 3.0.04, allowing for the execution of arbitrary system commands.

Understanding CVE-2018-3955

This CVE involves an OS Command Injection vulnerability in Linksys routers, enabling attackers to gain full control of the device.

What is CVE-2018-3955?

The vulnerability allows the execution of arbitrary system commands on affected Linksys routers.
It can be triggered by manipulating network configuration information through the 'Domain Name' input field on the web portal.

The Impact of CVE-2018-3955

CVSS Base Score: 7.2 (High)
Attack Vector: Network
Confidentiality Impact: High
Integrity Impact: High
Availability Impact: High
Privileges Required: High
The vulnerability poses a significant risk as it grants attackers full control over the compromised device.

Technical Details of CVE-2018-3955

This section provides more in-depth technical insights into the vulnerability.

Vulnerability Description

The vulnerability allows for the execution of arbitrary system commands on the affected Linksys routers.
It involves manipulating network configuration information through a specific input field on the web portal.

Affected Systems and Versions

Affected Products: Linksys ESeries E1200, E2500
Vulnerable Versions:
E1200: Firmware Version 2.0.09
E2500: Firmware Version 3.0.04

Exploitation Mechanism

Attackers can exploit the vulnerability by submitting malicious data through the 'wan_domain' POST parameter to the apply.cgi script.
The manipulation of the 'Domain Name' input field triggers the execution of arbitrary system commands.
The 'preinit' binary, upon receiving a specific signal, invokes a function that leads to the compromise of the device.

Mitigation and Prevention

Protecting systems from CVE-2018-3955 requires immediate actions and long-term security practices.

Immediate Steps to Take

Update the firmware of the affected Linksys routers to the latest secure version.
Monitor network traffic for any suspicious activities that might indicate exploitation attempts.
Restrict access to the web portal of the routers to authorized personnel only.

Long-Term Security Practices

Regularly audit and update router configurations to ensure security best practices are implemented.
Conduct security training for network administrators to enhance awareness of potential vulnerabilities and attack vectors.

Patching and Updates

Linksys should release patches addressing the CVE-2018-3955 vulnerability to eliminate the risk of exploitation and enhance the security of the affected routers.