EUVD-2025-12664

Comprehensive Technical Analysis of EUVD-2025-12664

1. Vulnerability Assessment and Severity Evaluation

Vulnerability Description: YesWiki, a PHP-based wiki system, has a critical vulnerability in versions prior to 4.5.4. This vulnerability allows unauthenticated users to initiate and download site backups. The backup files are created with predictable filenames, enabling malicious actors to exploit this feature to either fill up the file system with numerous backup requests or download sensitive site information.

Severity Evaluation: The vulnerability has a CVSS (Common Vulnerability Scoring System) base score of 10.0, which is the highest possible score, indicating a critical severity level. The CVSS vector CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H breaks down as follows:

• Attack Vector (AV): Network (N) - The vulnerability is exploitable over the network.
• Attack Complexity (AC): Low (L) - The attack requires minimal skill and resources.
• Privileges Required (PR): None (N) - No authentication is required to exploit the vulnerability.
• User Interaction (UI): None (N) - No user interaction is required.
• Scope (S): Changed (C) - The vulnerability affects resources beyond the security scope managed by the security authority.
• Confidentiality (C): High (H) - There is a high impact on the confidentiality of the system.
• Integrity (I): High (H) - There is a high impact on the integrity of the system.
• Availability (A): High (H) - There is a high impact on the availability of the system.

2. Potential Attack Vectors and Exploitation Methods

Attack Vectors:

• Unauthenticated Backup Creation: An attacker can send requests to the YesWiki system to create backups without needing any authentication.
• Predictable Filenames: The backup files are created with predictable filenames, allowing attackers to easily identify and download them.

Exploitation Methods:

• Denial of Service (DoS): By repeatedly requesting backups, an attacker can fill up the file system, leading to a denial of service.
• Data Exfiltration: An attacker can download the backup files, which may contain sensitive information such as user data, configuration files, and other critical site information.

3. Affected Systems and Software Versions

Affected Systems:

• YesWiki versions prior to 4.5.4.

Software Versions:

• All versions of YesWiki below 4.5.4 are vulnerable.

4. Recommended Mitigation Strategies

Immediate Actions:

• Upgrade: Upgrade to YesWiki version 4.5.4 or later, which includes the patch for this vulnerability.
• Access Control: Implement additional access controls to restrict backup creation and download to authenticated users only.
• Monitoring: Monitor for unusual backup creation activities and investigate any suspicious behavior.

Long-Term Strategies:

• Regular Updates: Ensure that all software, including YesWiki, is regularly updated to the latest versions.
• Security Audits: Conduct regular security audits to identify and mitigate potential vulnerabilities.
• Intrusion Detection: Implement intrusion detection systems (IDS) to detect and respond to unauthorized activities.

5. Impact on European Cybersecurity Landscape

Impact Analysis:

• Data Breaches: The vulnerability can lead to significant data breaches, exposing sensitive information and violating data protection regulations such as GDPR.
• Service Disruption: The potential for denial of service attacks can disrupt critical services, affecting business continuity and user trust.
• Reputation Damage: Organizations using vulnerable versions of YesWiki may suffer reputational damage if exploited.

Regulatory Compliance:

• GDPR: Organizations must ensure compliance with GDPR by protecting personal data and reporting breaches within the required timeframe.
• NIS Directive: Critical infrastructure providers must adhere to the Network and Information Systems (NIS) Directive, ensuring robust cybersecurity measures are in place.

6. Technical Details for Security Professionals

Technical Overview:

• Vulnerability Type: Authentication Bypass and Information Disclosure.
• Exploit Mechanism: The vulnerability is exploited by sending unauthenticated requests to the backup creation endpoint, which generates and stores backup files with predictable filenames.
• Patch Details: The patch in version 4.5.4 introduces authentication checks for backup creation and download, ensuring that only authorized users can perform these actions.

References:

• GitHub Advisory: GHSA-wc9g-6j9w-hr95
• Patch Commit: 0d4efc880a727599fa4f6d7a64cc967afe475530

Conclusion: This vulnerability in YesWiki underscores the importance of regular software updates and robust access controls. Organizations must prioritize patching and implementing additional security measures to mitigate the risk of exploitation. The European cybersecurity landscape demands vigilance and proactive measures to protect against such critical vulnerabilities.