CVE-2019-25591: DNSS Domain Name Search Software DoS

CVE-2019-25591 Overview

CVE-2019-25591 is a buffer overflow vulnerability affecting DNSS Domain Name Search Software version 2.1.8. The vulnerability exists in the registration code input field and allows local attackers to crash the application by submitting an excessively long string. Attackers can trigger a denial of service by pasting a malicious registration code containing 300 repeated characters into the Name/Key field via the Register menu option.

Critical Impact

Local attackers can crash the DNSS application causing denial of service by exploiting improper input validation in the registration code field.

Affected Products

• DNSS Domain Name Search Software 2.1.8

Discovery Timeline

• 2026-03-22 - CVE CVE-2019-25591 published to NVD
• 2026-03-23 - Last updated in NVD database

Technical Details for CVE-2019-25591

Vulnerability Analysis

This vulnerability is classified as CWE-787 (Out-of-Bounds Write), a memory corruption issue that occurs when the application writes data past the boundaries of an allocated buffer. The DNSS Domain Name Search Software fails to properly validate the length of user-supplied input in the registration code field before copying it into a fixed-size buffer. When an attacker provides a string exceeding the expected buffer size, the application writes beyond the allocated memory region, corrupting adjacent memory and causing the application to crash.

The vulnerability requires local access to the system where the software is installed, limiting the attack surface to users who already have access to the target machine. No authentication is required to trigger the vulnerability, as it occurs during the software registration process which is typically accessible to any local user.

Root Cause

The root cause of this vulnerability is improper input validation and missing boundary checks in the registration code processing function. The application allocates a fixed-size buffer for the registration code input but fails to verify that user-supplied data does not exceed this allocation before performing memory copy operations. This lack of bounds checking allows attackers to overflow the buffer with excessive input data, leading to memory corruption.

Attack Vector

The attack vector is local, requiring an attacker to have access to the system where DNSS Domain Name Search Software is installed. The exploitation process involves navigating to the Register menu option within the application and pasting approximately 300 or more characters into the Name/Key input field. When the application attempts to process this oversized input, the buffer overflow is triggered, causing the application to crash. This results in a denial of service condition affecting the availability of the software.

Technical details regarding the specific exploitation method can be found in the Exploit-DB #46831 entry and the VulnCheck Advisory on DNSS DoS.

Detection Methods for CVE-2019-25591

Indicators of Compromise

• Unexpected crashes of the DNSS Domain Name Search Software application
• Application error logs showing access violations or memory corruption errors
• Evidence of unusually long strings in registration-related log entries or crash dumps

Detection Strategies

• Monitor for repeated application crashes in the DNSS software
• Implement endpoint detection rules to identify buffer overflow patterns targeting desktop applications
• Review Windows Event Logs for application fault events related to DNSS executable files

Monitoring Recommendations

• Configure application crash monitoring and alerting for DNSS software
• Deploy endpoint protection solutions capable of detecting exploitation attempts against desktop applications
• Establish baseline application behavior to identify anomalous crash patterns

How to Mitigate CVE-2019-25591

Immediate Actions Required

• Restrict local access to systems running vulnerable DNSS software to trusted users only
• Consider removing or disabling the DNSS software if it is not essential for operations
• Monitor for signs of exploitation attempts or unusual application behavior

Patch Information

No vendor patch information is currently available for this vulnerability. Users should check the NSA Auditor website for potential updates or contact the vendor directly for remediation guidance. Consider migrating to alternative domain name search software if no patch is released.

Workarounds

• Limit access to the system where DNSS is installed to trusted users only
• Disable or remove the DNSS software if not required for business operations
• Implement application whitelisting to prevent unauthorized software execution
• Use endpoint protection solutions to detect and block exploitation attempts