Description
The FTP Backup on the ADM does not properly sanitize filenames received from the FTP server when parsing directory listings. A malicious server or MITM attacker can craft filenames containing path traversal sequences, causing the client to write files outside the intended backup directory. A path traversal vulnerability may allow an attacker to overwrite arbitrary files on the system and potentially achieve privilege escalation or remote code execution. Affected products and versions include: from ADM 4.1.0 through ADM 4.3.3.ROF1 as well as from ADM 5.0.0 through ADM 5.1.2.RE51.
EPSS Score:
0%
Comprehensive Technical Analysis of EUVD-2026-8517
1. Vulnerability Assessment and Severity Evaluation
The vulnerability described in EUVD-2026-8517 pertains to a path traversal issue in the FTP Backup feature of ASUSTOR's ADM (ASUSTOR Data Master) software. This flaw arises from insufficient sanitization of filenames received from the FTP server during directory listing parsing. The severity of this vulnerability is rated with a CVSS Base Score of 9.2, indicating a critical risk.
CVSS Vector Breakdown:
- AV:N (Network Vector): The vulnerability is exploitable over the network.
- AC:L (Low Complexity): The attack requires low skill or resources to exploit.
- AT:P (Physical Attack Vector): The attack requires physical access to the device.
- PR:N (No Privileges Required): No privileges are needed to exploit the vulnerability.
- UI:N (No User Interaction): No user interaction is required for the attack to succeed.
- VC:H (High Confidentiality Impact): The vulnerability can lead to high confidentiality impact.
- VI:H (High Integrity Impact): The vulnerability can lead to high integrity impact.
- VA:H (High Availability Impact): The vulnerability can lead to high availability impact.
- SC:N (No Scope Change): The vulnerability does not change the security scope.
- SI:N (No Scope Integrity): The vulnerability does not affect the integrity of the security scope.
- SA:N (No Scope Availability): The vulnerability does not affect the availability of the security scope.
2. Potential Attack Vectors and Exploitation Methods
Attack Vectors:
- Malicious FTP Server: An attacker could set up a malicious FTP server that sends crafted filenames containing path traversal sequences to the ADM client.
- Man-in-the-Middle (MITM) Attack: An attacker could intercept and modify FTP communications to inject malicious filenames.
Exploitation Methods:
- Path Traversal: By crafting filenames with sequences like
../../, an attacker can manipulate the ADM client to write files outside the intended backup directory. - Arbitrary File Overwrite: This can lead to overwriting critical system files, potentially causing privilege escalation or remote code execution.
3. Affected Systems and Software Versions
The vulnerability affects the following versions of ASUSTOR ADM:
- ADM 4.1.0 through ADM 4.3.3.ROF1
- ADM 5.0.0 through ADM 5.1.2.RE51
4. Recommended Mitigation Strategies
Immediate Mitigation:
- Disable FTP Backup: Temporarily disable the FTP Backup feature until a patch is applied.
- Network Segmentation: Isolate the ADM devices from untrusted networks to minimize exposure.
- Monitoring: Implement monitoring to detect unusual file write activities outside the intended backup directory.
Long-Term Mitigation:
- Patch Application: Apply the latest security patches provided by ASUSTOR.
- Input Validation: Ensure that all inputs, especially filenames, are properly sanitized and validated.
- Secure Communication: Use secure communication protocols like SFTP or FTPS to mitigate MITM attacks.
5. Impact on European Cybersecurity Landscape
The vulnerability poses a significant risk to organizations and individuals using ASUSTOR ADM within the European Union. Given the critical nature of the vulnerability, it could lead to widespread data breaches, system compromises, and potential violations of GDPR regulations if sensitive data is exposed or manipulated.
6. Technical Details for Security Professionals
Technical Analysis:
- Root Cause: The root cause is the lack of proper sanitization of filenames received from the FTP server.
- Exploitation: An attacker can exploit this by sending filenames with path traversal sequences, causing the ADM client to write files to unintended locations.
- Impact: This can result in arbitrary file overwrites, leading to privilege escalation, remote code execution, or system compromise.
Detection and Response:
- Log Analysis: Review logs for unusual file write activities, especially outside the intended backup directory.
- Intrusion Detection Systems (IDS): Deploy IDS to detect and alert on suspicious FTP traffic patterns.
- Incident Response: Have an incident response plan in place to quickly address any detected exploitation attempts.
References:
By addressing this vulnerability promptly and comprehensively, organizations can mitigate the risk of exploitation and ensure the security and integrity of their systems.