CVE-2019-3871 Explained : Impact and Mitigation

PowerDNS Authoritative Server versions earlier than 4.0.7 and 4.1.7 are affected by a security issue that allows remote attackers to exploit inadequate validation of user data, potentially leading to denial of service and information disclosure.

Understanding CVE-2019-3871

This CVE involves a vulnerability in PowerDNS Authoritative Server versions prior to 4.0.7 and 4.1.7, allowing for potential denial of service and information leakage.

What is CVE-2019-3871?

The vulnerability stems from insufficient validation of user data in the HTTP Connector of the Remote backend in PowerDNS Authoritative Server.
Attackers can craft a HTTP request from a DNS query, potentially causing denial of service by connecting the server to an invalid endpoint.
There is also a risk of information disclosure by connecting the server to an internal endpoint and extracting sensitive data from the response.

The Impact of CVE-2019-3871

CVSS Base Score: 6.5 (Medium Severity)
Attack Vector: Network
Attack Complexity: Low
Confidentiality Impact: Low
Integrity Impact: None
Availability Impact: Low
Privileges Required: None
User Interaction: None
Scope: Unchanged

Technical Details of CVE-2019-3871

PowerDNS Authoritative Server versions prior to 4.0.7 and 4.1.7 are susceptible to exploitation due to inadequate validation of user data.

Vulnerability Description

The vulnerability allows remote attackers to manipulate DNS queries into HTTP requests, potentially causing denial of service or information leakage.

Affected Systems and Versions

Affected Product: PowerDNS
Vendor: The PowerDNS Project
Vulnerable Versions: 4.0.7 and 4.1.7

Exploitation Mechanism

Attackers can exploit the vulnerability by crafting malicious HTTP requests from DNS queries, leading to denial of service or information disclosure.

Mitigation and Prevention

To address CVE-2019-3871, follow these mitigation strategies:

Immediate Steps to Take

Update PowerDNS Authoritative Server to versions 4.0.7 or 4.1.7 to mitigate the vulnerability.
Monitor network traffic for any suspicious activity that could indicate exploitation of the issue.

Long-Term Security Practices

Regularly update and patch PowerDNS Authoritative Server to protect against known vulnerabilities.
Implement network segmentation to limit the impact of potential attacks.

Patching and Updates

Stay informed about security advisories and updates from PowerDNS to promptly apply patches and protect your systems.