CVE-2019-25475: SQL Server Password Changer DoS Flaw

CVE-2019-25475 Overview

CVE-2019-25475 is a buffer overflow vulnerability affecting SQL Server Password Changer version 1.90. This memory corruption flaw allows local attackers to crash the application by supplying an oversized payload to input fields. Specifically, attackers can inject 6000 bytes of data into the User Name and Registration Code fields to trigger a denial of service condition.

Critical Impact

Local attackers can crash SQL Server Password Changer 1.90 through buffer overflow, causing denial of service and potentially disrupting database administration workflows.

Affected Products

• SQL Server Password Changer 1.90

Discovery Timeline

• 2026-03-11 - CVE CVE-2019-25475 published to NVD
• 2026-03-12 - Last updated in NVD database

Technical Details for CVE-2019-25475

Vulnerability Analysis

This vulnerability is classified as CWE-787 (Out-of-bounds Write), indicating improper restriction of operations within the bounds of a memory buffer. The flaw exists in how SQL Server Password Changer 1.90 handles user-supplied input in the User Name and Registration Code fields without proper bounds checking.

When an attacker provides an excessively long string (approximately 6000 bytes) to these input fields, the application fails to validate the input length before copying it into a fixed-size buffer. This overflow condition corrupts adjacent memory, causing the application to crash and resulting in a denial of service.

The local attack vector means an attacker must have local access to the system where SQL Server Password Changer is installed. While the vulnerability does not allow for code execution based on available information, it can disrupt administrative operations and potentially be used as part of a larger attack chain.

Root Cause

The root cause is insufficient input validation and bounds checking when processing user-supplied data in the registration fields. The application allocates a fixed-size buffer for the User Name and Registration Code inputs but does not enforce length restrictions before copying data into these buffers, allowing attackers to write beyond the allocated memory boundaries.

Attack Vector

The attack requires local access to the system running SQL Server Password Changer 1.90. An attacker can exploit this vulnerability by:

1. Launching the SQL Server Password Changer application
2. Navigating to the registration or user name input fields
3. Supplying approximately 6000 bytes of arbitrary data
4. Triggering the buffer overflow, which crashes the application

The vulnerability is exploited through the application's graphical user interface, making it accessible to any user with local system access. Technical details and proof-of-concept information can be found in the Exploit-DB #47318 advisory.

Detection Methods for CVE-2019-25475

Indicators of Compromise

• Unexpected crashes of SQL Server Password Changer application
• Application error logs showing memory access violations or buffer overflow exceptions
• Windows Event Viewer entries indicating application faults in SQL Server Password Changer processes

Detection Strategies

• Monitor for repeated crashes of the SQL Server Password Changer application process
• Implement application whitelisting to detect unauthorized attempts to interact with the vulnerable software
• Deploy endpoint detection and response (EDR) solutions to identify buffer overflow exploitation attempts

Monitoring Recommendations

• Enable Windows Error Reporting to capture crash dumps from the vulnerable application
• Monitor endpoint logs for application fault events related to SQL Server Password Changer
• Review system stability logs for patterns indicating denial of service attempts

How to Mitigate CVE-2019-25475

Immediate Actions Required

• Restrict local access to systems running SQL Server Password Changer 1.90 to authorized administrators only
• Consider removing or disabling SQL Server Password Changer until a patched version is available
• Implement application control policies to prevent unauthorized users from launching the vulnerable application

Patch Information

No vendor patch information is currently available for this vulnerability. Users should monitor the vendor's official channels for security updates. Additional technical details are available in the VulnCheck Advisory.

Workarounds

• Limit access to the vulnerable application to trusted administrators only
• Deploy endpoint protection solutions capable of detecting buffer overflow exploitation attempts
• Consider using alternative SQL Server password management tools that have active security maintenance
• Implement strict access controls on workstations where the vulnerable application is installed