CVE-2020-3511 Explained : Impact and Mitigation

A vulnerability in the ISDN subsystem of Cisco IOS Software and Cisco IOS XE Software could allow an unauthenticated, adjacent attacker to cause a reload of an affected device, resulting in a denial of service (DoS) condition.

Understanding CVE-2020-3511

This CVE involves a denial of service vulnerability in Cisco IOS and IOS XE Software due to insufficient input validation in processing ISDN Q.931 messages.

What is CVE-2020-3511?

The vulnerability allows an attacker to send a malicious ISDN Q.931 message to crash the process, leading to a device reload and DoS.

The Impact of CVE-2020-3511

CVSS Base Score: 7.4 (High Severity)
Attack Vector: Adjacent Network
Availability Impact: High

Technical Details of CVE-2020-3511

This section provides more technical insights into the vulnerability.

Vulnerability Description

The vulnerability arises from insufficient input validation in processing ISDN Q.931 messages.

Affected Systems and Versions

Affected Product: Cisco IOS
Affected Versions: Not applicable (n/a)

Exploitation Mechanism

Attacker sends a malicious ISDN Q.931 message to the affected device
Successful exploit crashes the process, causing a device reload

Mitigation and Prevention

Protecting systems from this vulnerability is crucial to prevent potential DoS attacks.

Immediate Steps to Take

Apply vendor-provided patches or updates
Implement network segmentation to limit exposure
Monitor network traffic for any suspicious activity

Long-Term Security Practices

Regularly update and patch software and firmware
Conduct security assessments and audits periodically
Educate users on identifying and reporting suspicious activities

Patching and Updates

Refer to the vendor's security advisory for specific patch details and instructions