EUVD-2023-2666

Comprehensive Technical Analysis of EUVD-2023-2666

1. Vulnerability Assessment and Severity Evaluation

Vulnerability Description: The vulnerability in XWiki Rendering, identified as EUVD-2023-2666 (CVE-2023-37908), allows the injection of arbitrary HTML code during XHTML rendering due to insufficient cleaning and validation of attribute names. This can lead to cross-site scripting (XSS) attacks, which can be exploited via malicious links in content supporting XWiki syntax, such as comments.

Severity Evaluation:

• Base Score: 9.1 (CVSS 3.1)
• Vector String: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:H

The high base score indicates a critical vulnerability. The attack vector is network-based (AV:N), requires low complexity (AC:L), and low privileges (PR:L). User interaction is required (UI:R), and the scope is changed (S:C). The impact on confidentiality, integrity, and availability is high (C:H/I:H/A:H).

2. Potential Attack Vectors and Exploitation Methods

Attack Vectors:

• Malicious Links: An attacker can inject malicious JavaScript code into links within XWiki content. When a user hovers over these links, the malicious code is executed.
• Comments and User-Generated Content: Any content that supports XWiki syntax, such as comments, can be used to inject malicious code.

Exploitation Methods:

• XSS Attacks: By injecting malicious JavaScript, an attacker can perform actions such as stealing session cookies, redirecting users to malicious sites, or executing unauthorized actions on behalf of the user.
• Privilege Escalation: If the affected user has programming rights, the attacker can execute server-side code, leading to further compromise of the XWiki instance.

3. Affected Systems and Software Versions

Affected Versions:

• XWiki Rendering versions from 14.6-rc-1 to 14.10.3
• XWiki Rendering versions before 15.0 RC1

Patched Versions:

• XWiki 14.10.4
• XWiki 15.0 RC1

4. Recommended Mitigation Strategies

Immediate Actions:

• Upgrade: Upgrade to XWiki 14.10.4 or 15.0 RC1, which include the patch for this vulnerability.
• Monitoring: Implement monitoring for suspicious activities, such as unexpected JavaScript execution or unauthorized actions.

Long-Term Strategies:

• Input Validation: Ensure robust input validation and sanitization for all user-generated content.
• Content Security Policy (CSP): Implement a strong CSP to mitigate XSS attacks.
• Regular Audits: Conduct regular security audits and code reviews to identify and fix similar vulnerabilities.

5. Impact on European Cybersecurity Landscape

Regulatory Compliance:

• GDPR: This vulnerability can lead to unauthorized access to personal data, violating GDPR regulations.
• NIS Directive: Organizations in critical sectors must ensure the integrity and availability of their systems, which this vulnerability threatens.

Industry Impact:

• Data Breaches: Potential data breaches can affect user trust and lead to financial losses.
• Reputation: Compromised systems can damage the reputation of organizations using XWiki.

6. Technical Details for Security Professionals

Vulnerability Details:

• Root Cause: Insufficient cleaning and validation of attribute names during XHTML rendering.
• Exploit Mechanism: The attribute data-xwiki-translated-attribute- was printed without proper validation, allowing the injection of arbitrary HTML code.

Patch Details:

• Fix: The patch removes characters not allowed in data attributes and validates the cleaned attribute again.
• Implementation: The fix is implemented in XWiki 14.10.4 and 15.0 RC1.

References:

• GitHub Advisory 1
• GitHub Advisory 2
• NVD CVE-2023-37908
• GitHub Commit
• XWiki Rendering Repository
• XWiki Jira Issue

Conclusion: This vulnerability highlights the importance of robust input validation and sanitization in preventing XSS attacks. Organizations using XWiki should prioritize upgrading to the patched versions to mitigate the risk of exploitation. Regular security audits and adherence to best practices can help prevent similar vulnerabilities in the future.