CVE-2020-7663 : Security Advisory and Response

WebSocket-extensions ruby module prior to 0.1.5 is vulnerable to Denial of Service (DoS) via Regex Backtracking.

Understanding CVE-2020-7663

This CVE involves a vulnerability in the websocket-extensions ruby module that allows for a Denial of Service attack through Regex Backtracking.

What is CVE-2020-7663?

The websocket-extensions ruby module prior to version 0.1.5 is susceptible to a Denial of Service (DoS) attack due to Regex Backtracking. An attacker can exploit this by providing a malicious payload with the Sec-WebSocket-Extensions header, causing a Regular Expression Denial of Service (ReDoS) on a single-threaded server.

The Impact of CVE-2020-7663

This vulnerability could be abused by malicious actors to conduct a Regex Denial Of Service (ReDoS) attack, potentially leading to service disruption and server unavailability.

Technical Details of CVE-2020-7663

The technical aspects of the CVE provide insight into the vulnerability and its implications.

Vulnerability Description

The extension parser in websocket-extensions ruby module may take quadratic time when parsing a header with an unclosed string parameter value containing a repeating two-byte sequence, enabling a ReDoS attack.

Affected Systems and Versions

Product: websocket-extensions (ruby)
Vendor: n/a
Versions Affected: All versions prior to 0.1.5

Exploitation Mechanism

Attackers can exploit the vulnerability by providing a malicious payload with the Sec-WebSocket-Extensions header, causing a ReDoS attack on a single-threaded server.

Mitigation and Prevention

Protecting systems from CVE-2020-7663 requires immediate actions and long-term security practices.

Immediate Steps to Take

Update the websocket-extensions ruby module to version 0.1.5 or later to mitigate the vulnerability.
Monitor and restrict input data to prevent malicious payloads that could trigger ReDoS attacks.

Long-Term Security Practices

Regularly update software and libraries to patch known vulnerabilities.
Implement input validation and sanitization to prevent Regex-based attacks.

Patching and Updates

Stay informed about security advisories and updates related to websocket-extensions (ruby) to apply patches promptly.