EUVD-2023-2794

Comprehensive Technical Analysis of EUVD-2023-2794

1. Vulnerability Assessment and Severity Evaluation

The vulnerability EUVD-2023-2794 affects the XWiki Platform, a generic wiki platform offering runtime services for applications. The issue is a reflected cross-site scripting (XSS) attack in the page creation form, which can be exploited when document names are validated according to a name strategy (disabled by default). This vulnerability allows an attacker to execute arbitrary actions with the rights of the user opening the malicious link. Depending on the user's rights, this may lead to remote code execution and full read and write access to the entire XWiki installation.

Severity Evaluation:

• CVSS Base Score: 9.7
• CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H

The high base score indicates a critical vulnerability due to the potential for significant impact on confidentiality, integrity, and availability. The attack vector is network-based (AV:N), requires low complexity (AC:L), no privileges (PR:N), and user interaction (UI:R). The scope is changed (S:C), and the impact on confidentiality, integrity, and availability is high (C:H/I:H/A:H).

2. Potential Attack Vectors and Exploitation Methods

Attack Vectors:

• Reflected XSS: An attacker can craft a malicious URL that, when clicked by a user, injects malicious scripts into the page creation form.
• Phishing: Attackers can send phishing emails containing the malicious link to users with elevated privileges.

Exploitation Methods:

• Script Injection: The attacker injects malicious JavaScript code into the page creation form, which is then executed in the context of the user's session.
• Session Hijacking: The injected script can steal session cookies or perform actions on behalf of the user.
• Remote Code Execution: If the user has administrative privileges, the attacker can execute arbitrary code on the server.

3. Affected Systems and Software Versions

Affected Versions:

• XWiki Platform versions starting from 12.0-rc-1 up to but not including 14.10.12.
• XWiki Platform versions starting from 15.0-rc-1 up to but not including 15.5-rc-1.

Patched Versions:

• XWiki Platform 14.10.12
• XWiki Platform 15.5-rc-1

4. Recommended Mitigation Strategies

Immediate Mitigation:

• Upgrade: Upgrade to the patched versions (14.10.12 or 15.5-rc-1) as soon as possible.
• Manual Patch: Apply the changes from the fix to the vulnerable template file createinline.vm if upgrading is not immediately feasible.

Additional Mitigation:

• Input Validation: Ensure that all user inputs are properly validated and sanitized.
• Content Security Policy (CSP): Implement a strong CSP to mitigate the impact of XSS attacks.
• User Education: Educate users about the risks of clicking on suspicious links and the importance of verifying the source of emails.

5. Impact on European Cybersecurity Landscape

The vulnerability poses a significant risk to organizations using the XWiki Platform, particularly those in sectors where data integrity and confidentiality are critical, such as healthcare, finance, and government. The potential for remote code execution and full access to the XWiki installation can lead to data breaches, unauthorized access, and service disruptions. Given the widespread use of wiki platforms for collaboration and documentation, this vulnerability underscores the need for robust security practices and timely patch management.

6. Technical Details for Security Professionals

Vulnerable Component:

• The vulnerability resides in the createinline.vm template file, which is part of XWiki's WAR (Web Application Archive).

Fix Details:

• The issue has been addressed by adding appropriate escaping to the vulnerable template file. The specific commit that includes the fix can be found at: GitHub Commit.

References:

• GitHub Security Advisory
• NVD Entry
• XWiki Jira Issue

EPSS Score:

• The EPSS (Exploit Prediction Scoring System) score of 75 indicates a high likelihood of exploitation in the wild.

ENISA IDs:

• Product IDs:
  • 1fbd0fdb-e22e-36b1-b14a-24db049b87ee (XWiki Platform 12.0-rc-1, < 14.10.12)
  • 3c0cb425-ba75-3317-b56a-85ab072603f9 (XWiki Platform 15.0-rc-1, < 15.5-rc-1)
• Vendor ID: 92b5f65f-73c7-3fa3-acbd-51b6d80f2b93 (XWiki)

Conclusion

The vulnerability EUVD-2023-2794 in the XWiki Platform is critical and requires immediate attention. Organizations should prioritize upgrading to the patched versions or applying the manual fix to mitigate the risk of XSS attacks and potential remote code execution. Enhanced input validation, strong CSP implementation, and user education are essential complementary measures to ensure the security of XWiki installations.