CVE-2020-5409 : Exploit Details and Defense Strategies

Pivotal Concourse, most versions prior to 6.0.0, allows redirects to untrusted websites in its login flow, potentially exposing user access tokens. This vulnerability has a CVSS base score of 7.6.

Understanding CVE-2020-5409

Pivotal Concourse is affected by an open redirect vulnerability in the /sky/login endpoint.

What is CVE-2020-5409?

Pivotal Concourse versions prior to 6.0.0 are susceptible to redirects to untrusted websites during the login process, enabling attackers to obtain user access tokens.

The Impact of CVE-2020-5409

CVSS Base Score: 7.6 (High Severity)
Attack Vector: Network
User Interaction: Required
Availability Impact: High
Similar to: CVE-2018-15798

Technical Details of CVE-2020-5409

Pivotal Concourse's vulnerability details and affected systems.

Vulnerability Description

The vulnerability allows remote unauthenticated attackers to trick users into clicking on malicious links, leading to access token compromise.

Affected Systems and Versions

Affected Product: Concourse
Vendor: Pivotal
Vulnerable Versions:
Concourse < 5.2.8
Concourse < 5.5.10
Concourse < 5.8.1
Concourse < 6.0.0

Exploitation Mechanism

Attackers exploit the OAuth redirect link to direct users to untrusted websites, gaining access to their Concourse access tokens.

Mitigation and Prevention

Protecting systems from CVE-2020-5409 and enhancing overall security.

Immediate Steps to Take

Update Concourse to version 6.0.0 or newer to mitigate the vulnerability.
Avoid clicking on suspicious links in the login flow.

Long-Term Security Practices

Educate users on phishing awareness and safe browsing practices.
Implement multi-factor authentication for enhanced security.

Patching and Updates

Regularly apply security patches and updates to Concourse to address known vulnerabilities.