CVE-2020-5207 : Vulnerability Insights and Analysis

In Ktor before 1.3.0, request smuggling is possible when running behind a proxy that doesn't handle Content-Length and Transfer-Encoding properly or doesn't handle \n as a headers separator.

Understanding CVE-2020-5207

In Ktor before version 1.3.0, a vulnerability exists that allows request smuggling under specific conditions.

What is CVE-2020-5207?

CVE-2020-5207 is a vulnerability in Ktor.io where request smuggling can occur due to improper handling of Content-Length, Transfer-Encoding, or header separators by a proxy.

The Impact of CVE-2020-5207

The vulnerability has a CVSS base score of 5.4, indicating a medium severity issue with low confidentiality and integrity impacts. It requires user interaction and has a low attack complexity.

Technical Details of CVE-2020-5207

Vulnerability Description

Request smuggling is possible in Ktor before 1.3.0 when behind a misconfigured proxy, leading to potential security risks.

Affected Systems and Versions

Product: Ktor
Vendor: Ktor.io
Versions Affected: < 1.3.0

Exploitation Mechanism

The vulnerability arises when a proxy mishandles Content-Length, Transfer-Encoding, or header separators, allowing malicious actors to manipulate requests.

Mitigation and Prevention

Immediate Steps to Take

Update Ktor to version 1.3.0 or newer to mitigate the vulnerability.
Ensure proxies properly handle Content-Length, Transfer-Encoding, and header separators.

Long-Term Security Practices

Regularly monitor and update proxy configurations to prevent request smuggling vulnerabilities.

Patching and Updates

Stay informed about security advisories and promptly apply patches to address known vulnerabilities.