CVE-2025-47812
KEVWing FTP Server Improper Neutralization of Null Byte or NUL Character Vulnerability
Weakness (CWE)
CVSS Vector
v3.1- Attack Vector
- Network
- Attack Complexity
- Low
- Privileges Required
- None
- User Interaction
- None
- Scope
- Changed
- Confidentiality
- High
- Integrity
- High
- Availability
- High
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.
Comprehensive Technical Analysis of CVE-2025-47812
1. Vulnerability Assessment and Severity Evaluation
CVE ID: CVE-2025-47812 CISA Vulnerability Name: Wing FTP Server Improper Neutralization of Null Byte or NUL Character Vulnerability CVSS Score: 10
The vulnerability in Wing FTP Server before version 7.4.4 involves the improper handling of null bytes ('\0') in the user and admin web interfaces. This mishandling allows for the injection of arbitrary Lua code into user session files, leading to remote code execution (RCE) with the privileges of the FTP service, which typically runs as root or SYSTEM. The CVSS score of 10 indicates the highest level of severity, reflecting the potential for complete server compromise.
2. Potential Attack Vectors and Exploitation Methods
Attack Vectors:
- Anonymous FTP Accounts: The vulnerability can be exploited via anonymous FTP accounts, making it accessible to any attacker without the need for authentication.
- Web Interface: The user and admin web interfaces are the primary points of entry for this vulnerability.
Exploitation Methods:
- Null Byte Injection: Attackers can inject null bytes into input fields, which are not properly neutralized by the server.
- Lua Code Injection: By injecting Lua code, attackers can execute arbitrary system commands with elevated privileges.
- Remote Code Execution: The injected Lua code can be used to execute system commands, 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: Upgrade to Wing FTP Server version 7.4.4 or later, which addresses the vulnerability.
- Disable Anonymous Access: If upgrading is not immediately possible, disable anonymous FTP access to limit exposure.
- Network Segmentation: Isolate the FTP server from critical systems to minimize the impact of a potential compromise.
Long-Term Strategies:
- Regular Patching: Implement a regular patching and update schedule for all software, including Wing FTP Server.
- Monitoring and Logging: Enhance monitoring and logging to detect and respond to suspicious activities.
- Access Controls: Implement strict access controls and authentication mechanisms to limit unauthorized access.
5. Impact on Cybersecurity Landscape
The discovery and exploitation of CVE-2025-47812 highlight the critical importance of proper input validation and neutralization of special characters in web interfaces. This vulnerability underscores the need for:
- Robust Security Testing: Ensuring that all input fields are thoroughly tested for injection vulnerabilities.
- Proactive Patch Management: Quickly addressing vulnerabilities through timely updates and patches.
- Enhanced Security Awareness: Increasing awareness among developers and administrators about the risks associated with improper handling of null bytes and other special characters.
6. Technical Details for Security Professionals
Vulnerability Details:
- Input Handling: The vulnerability stems from the improper handling of null bytes in input fields, which are not properly sanitized or neutralized.
- Lua Code Execution: The injected Lua code can be used to execute system commands, leading to RCE with elevated privileges.
- Privilege Escalation: The FTP service typically runs with root or SYSTEM privileges, making the impact of this vulnerability severe.
Detection and Response:
- Intrusion Detection Systems (IDS): Implement IDS to detect unusual patterns of null byte injection.
- Log Analysis: Regularly analyze logs for signs of Lua code injection and unusual system commands.
- Incident Response: Develop and maintain an incident response plan to quickly address and mitigate any detected exploitation attempts.
References:
By addressing this vulnerability promptly and implementing robust security measures, organizations can significantly reduce the risk of a total server compromise and maintain the integrity of their systems.