CVE-2019-1840 : What You Need to Know

Cisco Prime Network Registrar Denial of Service Vulnerability

Understanding CVE-2019-1840

This CVE involves a vulnerability in the DHCPv6 packet processor of Cisco Prime Network Registrar, potentially leading to a denial of service (DoS) attack.

What is CVE-2019-1840?

The vulnerability allows an unauthenticated remote attacker to trigger a DoS condition by sending malformed DHCPv6 packets to the application, causing a server restart. It arises from inadequate validation of user input when a custom extension attempts to modify a DHCPv6 packet.

The Impact of CVE-2019-1840

Severity: Initially rated as High but lowered to Medium due to the need for custom extensions to exploit it
CVSS Base Score: 8.6 (High)
Attack Vector: Network
Availability Impact: High

Technical Details of CVE-2019-1840

The following technical details provide insight into the vulnerability:

Vulnerability Description

The vulnerability stems from insufficient validation of user input during DHCPv6 packet processing

Affected Systems and Versions

Affected Product: Cisco Prime Network Registrar
Versions Vulnerable: < 8.3(7) and < 9.1(2)

Exploitation Mechanism

Attack Complexity: Low
Privileges Required: None
Scope: Changed
User Interaction: None
Exploitation involves sending malformed DHCPv6 packets to the application

Mitigation and Prevention

Taking immediate steps and implementing long-term security practices are crucial to mitigate the risks associated with CVE-2019-1840.

Immediate Steps to Take

Disable custom extensions that attempt to modify DHCPv6 packets
Apply vendor-supplied patches or updates

Long-Term Security Practices

Regularly update and patch software to address vulnerabilities
Implement network segmentation to limit the impact of potential attacks

Patching and Updates

Ensure all systems are updated with the latest patches from Cisco