Description
In Wing FTP Server before 7.4.4. the user and admin web interfaces mishandle '\0' bytes, ultimately allowing injection of arbitrary Lua code into user session files. This can be used to execute arbitrary system commands with the privileges of the FTP service (root or SYSTEM by default). This is thus a remote code execution vulnerability that guarantees a total server compromise. This is also exploitable via anonymous FTP accounts.
EPSS Score:
0%
Comprehensive Technical Analysis of EUVD-2025-21009
1. Vulnerability Assessment and Severity Evaluation
Vulnerability Description: The vulnerability in Wing FTP Server before version 7.4.4 involves the mishandling of '\0' bytes in the user and admin web interfaces. This flaw allows for the injection of arbitrary Lua code into user session files, leading to the execution of arbitrary system commands with the privileges of the FTP service, which typically runs as root or SYSTEM. This is a critical remote code execution (RCE) vulnerability that can result in a total server compromise.
Severity Evaluation:
- CVSS Base Score: 10.0
- CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
The CVSS score of 10.0 indicates the highest level of severity. The vulnerability can be exploited remotely (AV:N) with low complexity (AC:L), requires no privileges (PR:N), and no user interaction (UI:N). The impact is severe, affecting confidentiality, integrity, and availability (C:H/I:H/A:H). The scope change (S:C) indicates that the vulnerability can affect resources beyond the security scope managed by the security authority of the vulnerable component.
2. Potential Attack Vectors and Exploitation Methods
Attack Vectors:
- Remote Exploitation: Attackers can exploit this vulnerability over the network without needing to authenticate or interact with users.
- Anonymous FTP Accounts: The vulnerability is exploitable via anonymous FTP accounts, making it easier for attackers to gain access.
Exploitation Methods:
- Lua Code Injection: Attackers can inject malicious Lua code into user session files by exploiting the mishandling of '\0' bytes.
- Command Execution: The injected Lua code can execute arbitrary system commands with elevated privileges, leading to full control over the server.
3. Affected Systems and Software Versions
Affected Software:
- Wing FTP Server versions before 7.4.4
Affected Systems:
- Any system running the vulnerable versions of Wing FTP Server, including but not limited to:
- Windows Servers
- Linux Servers
- Unix Servers
4. Recommended Mitigation Strategies
Immediate Actions:
- Upgrade: Immediately upgrade to Wing FTP Server version 7.4.4 or later.
- Disable Anonymous Access: Temporarily disable anonymous FTP access to reduce the attack surface.
- Network Segmentation: Isolate the FTP server from critical systems to limit the potential impact of a compromise.
Long-Term Strategies:
- Regular Patching: Implement a robust patch management program to ensure all software is up-to-date.
- Intrusion Detection: Deploy intrusion detection systems (IDS) to monitor for suspicious activity.
- Access Controls: Enforce strict access controls and use multi-factor authentication (MFA) for administrative access.
5. Impact on European Cybersecurity Landscape
Potential Impact:
- Widespread Compromise: Given the popularity of Wing FTP Server, this vulnerability poses a significant risk to organizations across Europe.
- Data Breaches: The ability to execute arbitrary commands can lead to data breaches, unauthorized access, and data exfiltration.
- Service Disruption: Attackers can disrupt FTP services, leading to operational downtime and financial losses.
Regulatory Compliance:
- GDPR: Organizations must ensure they comply with GDPR regulations, especially in terms of data protection and breach reporting.
- NIS Directive: Critical infrastructure providers must adhere to the Network and Information Systems (NIS) Directive to maintain security and resilience.
6. Technical Details for Security Professionals
Vulnerability Details:
- CWE Identifier: CWE-94 (Improper Control of Generation of Code ('Code Injection'))
- Exploit Mechanism: The vulnerability is triggered by the improper handling of '\0' bytes in user input, allowing for Lua code injection.
- Privilege Escalation: The injected code runs with the privileges of the FTP service, which is typically root or SYSTEM.
Detection and Response:
- Log Analysis: Monitor FTP server logs for unusual activity, such as unexpected Lua code execution or system command invocations.
- Behavioral Analysis: Use behavioral analysis tools to detect anomalous behavior indicative of a compromise.
- Incident Response: Have an incident response plan in place to quickly identify, contain, and remediate any security incidents.
References:
By addressing this vulnerability promptly and implementing robust security measures, organizations can mitigate the risk of a total server compromise and protect their critical assets.