CVE-2019-25363: WMV Convertor Buffer Overflow Vulnerability

CVE-2019-25363 Overview

CVE-2019-25363 is a stack-based buffer overflow vulnerability affecting WMV to AVI MPEG DVD WMV Convertor version 4.6.1217. The vulnerability exists in the license registration functionality where attackers can crash the application by providing an oversized license input. By generating a 6000-byte payload and pasting it into the 'License Name and License Code' field, attackers can trigger an application crash and potentially execute arbitrary code.

Critical Impact

This buffer overflow vulnerability allows attackers to crash the application through malicious input in the license registration fields, potentially leading to denial of service or code execution scenarios.

Affected Products

• WMV to AVI MPEG DVD WMV Convertor 4.6.1217

Discovery Timeline

• 2026-02-18 - CVE CVE-2019-25363 published to NVD
• 2026-02-19 - Last updated in NVD database

Technical Details for CVE-2019-25363

Vulnerability Analysis

This vulnerability is classified as CWE-121 (Stack-based Buffer Overflow), which occurs when a program copies data to a fixed-length buffer on the stack without proper bounds checking. In the case of WMV to AVI MPEG DVD WMV Convertor, the application fails to validate the length of user-supplied input in the license registration fields before copying it to a stack-allocated buffer.

The attack requires local access and user interaction, as the victim must launch the application and an attacker must input the malicious payload into the license fields. When a 6000-byte payload is entered into the 'License Name and License Code' field, the application's stack is corrupted, leading to an immediate crash. Depending on the system configuration and exploit sophistication, this could potentially be leveraged for arbitrary code execution.

Root Cause

The root cause of this vulnerability is improper input validation in the license registration component of WMV to AVI MPEG DVD WMV Convertor. The application allocates a fixed-size buffer on the stack for license data but does not enforce length restrictions on user input. When input exceeds the allocated buffer size, it overwrites adjacent stack memory, including the return address and saved registers, causing application instability or crash.

Attack Vector

This is a local attack vector requiring user interaction. An attacker must either have direct access to the system running the vulnerable software or convince a user to paste a malicious payload into the license registration fields. The attack can be executed by:

1. Generating a payload of approximately 6000 bytes
2. Opening the WMV to AVI MPEG DVD WMV Convertor application
3. Navigating to the license registration dialog
4. Pasting the oversized payload into the 'License Name and License Code' input fields
5. Triggering the buffer overflow when the application processes the input

Technical details and proof-of-concept information are available in the Exploit-DB #47563 advisory. Additional vulnerability information can be found in the VulnCheck Advisory on WMV Converter.

Detection Methods for CVE-2019-25363

Indicators of Compromise

• Unexpected application crashes of WMV to AVI MPEG DVD WMV Convertor with stack corruption indicators
• Presence of unusually large strings in application memory dumps related to license registration
• Windows Error Reporting (WER) crash dumps indicating stack buffer overflow in the converter application

Detection Strategies

• Deploy endpoint detection and response (EDR) solutions configured to monitor for stack-based buffer overflow patterns
• Implement application whitelisting policies to control which applications can execute on endpoints
• Monitor for suspicious process behavior associated with legacy media converter applications

Monitoring Recommendations

• Enable Windows Defender Exploit Guard with stack integrity checks for legacy applications
• Configure centralized logging to capture application crash events and analyze for patterns
• Implement SentinelOne's behavioral AI engine to detect anomalous application behavior indicative of exploitation attempts

How to Mitigate CVE-2019-25363

Immediate Actions Required

• Uninstall WMV to AVI MPEG DVD WMV Convertor version 4.6.1217 from all affected systems
• Consider migrating to actively maintained video conversion software with a strong security track record
• Implement application control policies to prevent execution of vulnerable software

Patch Information

No vendor patch is currently available for this vulnerability. The software vendor, Alloksoft, does not appear to be actively maintaining this product. Organizations should consider this software end-of-life and seek alternative solutions for video conversion needs. For historical reference, the Alloksoft Official Site and Alloksoft WMV Resource provide product information.

Workarounds

• Remove the vulnerable application from all production systems and replace with a supported alternative
• If removal is not immediately possible, restrict application usage to isolated systems without network connectivity
• Implement Windows Defender Application Guard or similar sandboxing to contain potential exploitation

# Remove the vulnerable application from Windows systems
# Run in elevated PowerShell

# Identify installed application
Get-WmiObject -Class Win32_Product | Where-Object { $_.Name -like "*WMV*Convertor*" }

# Uninstall if found (replace with actual product code)
# wmic product where name="WMV to AVI MPEG DVD WMV Convertor" call uninstall