EUVD-2025-29625

Comprehensive Technical Analysis of EUVD-2025-29625

1. Vulnerability Assessment and Severity Evaluation

The vulnerability described in EUVD-2025-29625 affects Linkr, a lightweight file delivery system. The core issue is the lack of integrity and authenticity verification for .linkr manifest files, which can lead to arbitrary file injection and potential remote code execution (RCE). The severity of this vulnerability is rated with a CVSS Base Score of 9.7, indicating a critical risk. The CVSS vector CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H highlights the following:

• Attack Vector (AV): Network (N) - The vulnerability can be exploited remotely over the network.
• Attack Complexity (AC): Low (L) - The attack requires minimal complexity to execute.
• Privileges Required (PR): None (N) - No special privileges are required to exploit the vulnerability.
• User Interaction (UI): Required (R) - The attack requires some form of user interaction, such as running the extract command.
• Scope (S): Changed (C) - The vulnerability affects a component that is outside the security scope of the vulnerable component.
• Confidentiality (C), Integrity (I), Availability (A): High (H) - The vulnerability has a high impact on confidentiality, integrity, and availability.

2. Potential Attack Vectors and Exploitation Methods

An attacker could exploit this vulnerability by:

• Manifest Tampering: Modifying a .linkr manifest file to include malicious URLs or file entries.
• File Injection: When a user runs the extract command, the client downloads and executes the attacker-supplied file without verification.
• Remote Code Execution: If the injected file is a malicious binary or script, it could be executed, leading to RCE.

3. Affected Systems and Software Versions

The vulnerability affects all versions of Linkr up to and including 2.0.0. The issue has been addressed in version 2.0.1, which includes a manifest integrity check.

4. Recommended Mitigation Strategies

• Update to Version 2.0.1 or Later: Users should immediately update to Linkr version 2.0.1 or later, which includes the necessary fixes.
• Use Trusted Manifests: Prior to updating, ensure that only trusted .linkr manifests are used.
• Manual Verification: Manually verify the integrity of manifests by comparing checksums.
• Host Manifests on Trusted Servers: Ensure that manifests are hosted on trusted and secure servers to prevent tampering.

5. Impact on European Cybersecurity Landscape

The vulnerability poses a significant risk to organizations and individuals using Linkr for file delivery. Given the potential for RCE, it could be exploited to compromise systems, exfiltrate data, and disrupt operations. The widespread use of Linkr in various sectors, including government, healthcare, and finance, amplifies the potential impact.

6. Technical Details for Security Professionals

• Manifest Integrity Check: Version 2.0.1 introduces a checksum-based integrity verification mechanism. The client compares the checksum of the original author-created manifest to the one being extracted and aborts the process if there is a mismatch.
• Warning Mechanism: If no original manifest is hosted, the client issues a warning, alerting users to potential risks.
• References:
  • GitHub Security Advisory: GHSA-6wph-mpv2-29xv
  • Commit Reference: 182e5ddaa51972e144005b500c4bcebf2fd1a6c0

Conclusion

The vulnerability in Linkr versions through 2.0.0 is critical and requires immediate attention. Organizations should prioritize updating to version 2.0.1 or later and implement additional security measures to mitigate risks. The potential for RCE underscores the importance of robust integrity and authenticity verification mechanisms in file delivery systems.