CVE-2019-25588 Overview
CVE-2019-25588 is a denial of service vulnerability affecting BulletProof FTP Server version 2019.0.0.50. The vulnerability exists in the DNS Address field within the Firewall settings, where a local attacker can crash the application by supplying an excessively long string. Specifically, an attacker can enable the DNS Address option in the Firewall settings and paste a buffer of 700 bytes to trigger a crash when the Test function is invoked.
Critical Impact
Local attackers can cause a complete denial of service by crashing the BulletProof FTP Server application through buffer overflow in the DNS Address field, disrupting FTP services and potentially impacting file transfer operations.
Affected Products
- BulletProof FTP Server 2019.0.0.50
- bpftpserver bulletproof_ftp_server
Discovery Timeline
- 2026-03-22 - CVE CVE-2019-25588 published to NVD
- 2026-03-25 - Last updated in NVD database
Technical Details for CVE-2019-25588
Vulnerability Analysis
This vulnerability is classified under CWE-1282, which relates to improper handling of excessively long input strings. The BulletProof FTP Server fails to properly validate the length of input provided to the DNS Address field in the Firewall settings interface. When a user provides an oversized buffer (approximately 700 bytes), the application does not implement adequate boundary checks, resulting in memory corruption that causes the application to crash.
The local attack vector requires an attacker to have access to the BulletProof FTP Server configuration interface. While this limits the scope of potential attackers, it remains a significant concern in environments where multiple users may have access to the server configuration or where an attacker has already gained local access through other means.
Root Cause
The root cause of this vulnerability is improper input validation in the DNS Address field handler. The application fails to implement proper buffer size checks when processing user-supplied input in the Firewall settings configuration. When the input exceeds the expected buffer size, memory corruption occurs, leading to an application crash. This represents a classic buffer overflow scenario where the application trusts user input without validating its length against the allocated buffer space.
Attack Vector
The attack requires local access to the BulletProof FTP Server application. An attacker must navigate to the Firewall settings within the application, enable the DNS Address option, and then paste a string of approximately 700 bytes or more into the DNS Address field. When the attacker clicks the Test function, the oversized input triggers memory corruption and causes the application to crash, resulting in denial of service.
The exploitation process involves:
- Opening BulletProof FTP Server configuration
- Navigating to Firewall settings
- Enabling the DNS Address option
- Pasting a buffer of 700+ bytes into the DNS Address field
- Clicking the Test function to trigger the crash
For detailed technical analysis, refer to the Exploit-DB #46875 entry and the VulnCheck Advisory on BPFTP Server.
Detection Methods for CVE-2019-25588
Indicators of Compromise
- Unexpected crashes or restarts of the BulletProof FTP Server process
- Application event logs showing unhandled exceptions or access violations related to the FTP server
- Configuration files showing unusually long DNS Address values in Firewall settings
- User activity logs indicating recent modifications to Firewall settings
Detection Strategies
- Monitor Windows Event Logs for BulletProof FTP Server application crashes or Dr. Watson entries
- Implement file integrity monitoring on BulletProof FTP Server configuration files to detect unauthorized modifications
- Set up process monitoring to detect unexpected termination of the FTP server service
- Review access logs for the server configuration interface to identify suspicious activity
Monitoring Recommendations
- Enable detailed logging for BulletProof FTP Server application events
- Configure alerts for service interruptions or unexpected process terminations
- Monitor system stability metrics for the host running BulletProof FTP Server
- Implement access controls and audit logging for administrative access to the FTP server configuration
How to Mitigate CVE-2019-25588
Immediate Actions Required
- Restrict access to the BulletProof FTP Server configuration interface to trusted administrators only
- Implement principle of least privilege for users with access to the FTP server host system
- Consider deploying application whitelisting to prevent unauthorized configuration changes
- Monitor for any suspicious activity around the FTP server configuration
Patch Information
No specific vendor patch information is available in the advisory data. Users should check the BPFTP Server Homepage for any available updates or patches. Consider upgrading to a newer version if one is available that addresses this vulnerability. For the latest software version, visit the BPFTP Server Windows Download page.
Workarounds
- Restrict physical and remote access to systems running BulletProof FTP Server to trusted personnel only
- Use Windows User Account Control (UAC) and role-based access to limit who can modify server configuration
- Consider running the FTP server with a dedicated service account with minimal privileges
- Implement network segmentation to isolate FTP server hosts from untrusted network segments
# Configuration example - Restrict access to BulletProof FTP Server
# Ensure only administrators can access the configuration directory
icacls "C:\Program Files\BulletProof FTP Server" /inheritance:r
icacls "C:\Program Files\BulletProof FTP Server" /grant:r Administrators:(OI)(CI)F
icacls "C:\Program Files\BulletProof FTP Server" /grant:r SYSTEM:(OI)(CI)F
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
