EUVD-2024-42160

Comprehensive Technical Analysis of EUVD-2024-42160

1. Vulnerability Assessment and Severity Evaluation

The vulnerability described in EUVD-2024-42160 affects the Nextcloud Desktop Client versions 3.13.1 through 3.13.3 on Linux. The issue involves synchronized files between the server and client becoming world writable or world readable. This vulnerability is rated with a CVSS Base Score of 9.1, indicating a critical severity level.

CVSS Vector Breakdown:

• AV:N (Network Vector): The vulnerability can be exploited remotely over the network.
• AC:L (Low Complexity): The attack requires low skill or resources to exploit.
• PR:N (No Privileges Required): No privileges are required to exploit the vulnerability.
• UI:N (No User Interaction): No user interaction is required to exploit the vulnerability.
• S:U (Unchanged): The scope of the vulnerability does not change.
• C:H (High Confidentiality Impact): There is a high impact on the confidentiality of the data.
• I:H (High Integrity Impact): There is a high impact on the integrity of the data.
• A:N (No Availability Impact): There is no impact on the availability of the system.

2. Potential Attack Vectors and Exploitation Methods

Attack Vectors:

• Remote Exploitation: An attacker can exploit this vulnerability remotely by accessing the synchronized files over the network.
• Local Exploitation: A local user with minimal privileges can read or modify the synchronized files, potentially leading to data leakage or corruption.

Exploitation Methods:

• Data Exfiltration: An attacker can read sensitive files that are synchronized between the Nextcloud server and client.
• Data Tampering: An attacker can modify the synchronized files, leading to data integrity issues.
• Malware Injection: An attacker can inject malicious code into the synchronized files, which can then be executed on the client or server.

3. Affected Systems and Software Versions

Affected Software:

• Nextcloud Desktop Client versions 3.13.1 through 3.13.3 on Linux.

Affected Systems:

• Any Linux system running the affected versions of the Nextcloud Desktop Client.

4. Recommended Mitigation Strategies

Immediate Mitigation:

• Upgrade to Version 3.13.4: Upgrade the Nextcloud Desktop Client to version 3.13.4, which includes the fix for this vulnerability.

Additional Mitigation:

• Access Controls: Implement strict access controls to limit who can access the synchronized files.
• Network Segmentation: Segment the network to isolate the Nextcloud server and client from untrusted networks.
• Monitoring and Logging: Enable monitoring and logging to detect any unauthorized access or modifications to the synchronized files.
• Regular Audits: Conduct regular security audits to ensure that the Nextcloud environment is secure.

5. Impact on European Cybersecurity Landscape

The vulnerability poses a significant risk to organizations and individuals using Nextcloud for file synchronization and sharing. Given the widespread use of Nextcloud in Europe, particularly in environments requiring high data confidentiality and integrity, the impact could be substantial. Organizations in sectors such as healthcare, finance, and government are particularly at risk due to the sensitive nature of the data they handle.

6. Technical Details for Security Professionals

Vulnerability Details:

• The issue arises due to improper file permission settings during the synchronization process, leading to files becoming world writable or world readable.
• The vulnerability is fixed in Nextcloud Desktop Client version 3.13.4, which corrects the file permission settings.

References:

• GitHub Issue
• GitHub Pull Request
• GitHub Pull Request
• Version Comparison
• Nextcloud Security Advisories

Aliases:

• CVE-2024-46958

Assigner:

• Mitre

EPSS:

• N/A

ENISA ID:

• Product: n/a
• Vendor: n/a

Conclusion: This vulnerability highlights the importance of timely updates and strict access controls in maintaining the security of file synchronization solutions. Organizations should prioritize updating to the patched version and implementing additional security measures to mitigate the risk associated with this critical vulnerability.