CVE-2017-16118 : Security Advisory and Response

CVE-2017-16118, published on April 26, 2018, addresses a vulnerability in the forwarded node module used by the Express.js framework. This vulnerability could lead to a denial of service (DoS) attack.

Understanding CVE-2017-16118

This CVE entry highlights a security issue in the Express.js framework due to a vulnerability in the forwarded node module.

What is CVE-2017-16118?

The vulnerability in the forwarded node module can be exploited to cause a denial of service by blocking the event loop when processing specially crafted input.

The Impact of CVE-2017-16118

The vulnerability can result in a DoS situation by blocking the event loop, affecting the availability of the affected system.

Technical Details of CVE-2017-16118

This section delves into the technical aspects of the CVE.

Vulnerability Description

The vulnerability arises from the forwarded module's handling of the X-Forwarded-For header, allowing for a regular expression denial of service attack.

Affected Systems and Versions

Product: forwarded node module
Vendor: HackerOne
Versions Affected: < 0.1.2

Exploitation Mechanism

The vulnerability is triggered by providing specially crafted input to the forwarded module, causing the event loop to be blocked and leading to a DoS condition.

Mitigation and Prevention

To address CVE-2017-16118, follow these mitigation strategies:

Immediate Steps to Take

Update the affected module to a version above 0.1.2 to mitigate the vulnerability.
Monitor and restrict input to prevent specially crafted data from triggering the DoS.

Long-Term Security Practices

Regularly update dependencies to ensure using the latest secure versions.
Implement input validation mechanisms to filter out potentially harmful input.

Patching and Updates

Apply patches provided by the vendor promptly to fix the vulnerability and enhance system security.