CVE-2021-21338 : Security Advisory and Response

A vulnerability has been discovered in TYPO3.CMS versions before 6.2.57, 7.6.51, 8.7.40, 9.5.25, 10.4.14, and 11.1.1 that allows for open redirection in Login Handling, enabling attackers to redirect to arbitrary content without requiring authentication, potentially leading to phishing attacks. This CVE has a CVSS base score of 4.7 (Medium severity).

Understanding CVE-2021-21338

This section provides insights into the impact, technical details, and mitigation steps related to the Open Redirection in Login Handling vulnerability.

What is CVE-2021-21338?

TYPO3.CMS, an open-source PHP-based web content management system, is affected by an open redirection vulnerability prior to versions 6.2.57, 7.6.51, 8.7.40, 9.5.25, 10.4.14, and 11.1.1. This flaw allows threat actors to redirect users to malicious content without the need for authentication, potentially facilitating phishing attacks.

The Impact of CVE-2021-21338

The vulnerability can be leveraged by attackers to craft phishing campaigns, leading unsuspecting users to malicious sites. With a base severity rating of 'Medium' and low integrity impact, the exploit poses a notable risk to affected systems.

Technical Details of CVE-2021-21338

Let's delve into the specifics of the vulnerability to understand affected systems, exploit mechanisms, and more.

Vulnerability Description

The flaw in Login Handling within TYPO3.CMS versions before 6.2.57, 7.6.51, 8.7.40, 9.5.25, 10.4.14, and 11.1.1 allows for open redirection, enabling attackers to redirect users to arbitrary content.

Affected Systems and Versions

The vulnerability impacts TYPO3.CMS versions ranging from 6.2.0 to 11.1.0, encompassing a wide range of installations.

Exploitation Mechanism

Attackers can manipulate URLs to redirect users to malicious sites, bypassing authentication mechanisms and potentially conducting phishing attacks.

Mitigation and Prevention

To safeguard systems from this vulnerability, immediate actions and long-term security practices are recommended.

Immediate Steps to Take

Users are advised to update their TYPO3.CMS installations to versions 6.2.57, 7.6.51, 8.7.40, 9.5.25, 10.4.14, or 11.1.1 to mitigate the risk of open redirection attacks.

Long-Term Security Practices

Implementing robust URL validation mechanisms, user input sanitization, and regular security audits can enhance the overall security posture of web applications.

Patching and Updates

Stay informed about security advisories from TYPO3 and promptly apply patches to address known vulnerabilities and protect against potential exploits.