CVE-2019-25331: AVS Audio Converter Buffer Overflow Flaw

CVE-2019-25331 Overview

CVE-2019-25331 is a local buffer overflow vulnerability affecting AVS Audio Converter version 9.1. This stack-based buffer overflow allows local attackers to overwrite CPU registers by manipulating the 'Exit folder' input field within the application. By crafting a specially designed text file containing 264 bytes of padding followed by register overwrite values, attackers can compromise the application and potentially execute arbitrary code on the target system.

Critical Impact

Local attackers can exploit this buffer overflow to overwrite CPU registers, potentially leading to arbitrary code execution and full system compromise.

Affected Products

• AVS Audio Converter 9.1
• AVS4YOU multimedia software suite

Discovery Timeline

• 2026-02-12 - CVE-2019-25331 published to NVD
• 2026-02-12 - Last updated in NVD database

Technical Details for CVE-2019-25331

Vulnerability Analysis

This vulnerability is classified as CWE-121 (Stack-based Buffer Overflow), a memory corruption flaw that occurs when a program writes data beyond the allocated buffer on the stack. In the case of AVS Audio Converter 9.1, the application fails to properly validate the length of user input provided through the 'Exit folder' field.

When a user supplies an excessively long string (264+ bytes) in this input field, the application writes past the allocated stack buffer, corrupting adjacent memory regions including saved return addresses and CPU registers. This type of vulnerability is particularly dangerous as it can allow attackers to redirect program execution flow to attacker-controlled code.

The local attack vector requires the attacker to have access to the system where AVS Audio Converter is installed. While this limits the attack surface compared to remote vulnerabilities, it remains a significant risk in environments where multiple users share systems or where malicious files might be distributed to users.

Root Cause

The root cause of this vulnerability lies in improper input validation and insufficient bounds checking in the AVS Audio Converter application. The 'Exit folder' input field does not enforce a maximum length restriction, allowing attackers to supply more data than the allocated stack buffer can safely accommodate. The absence of stack protection mechanisms such as stack canaries or Address Space Layout Randomization (ASLR) enforcement may further facilitate exploitation.

Attack Vector

The attack exploits the local interface of AVS Audio Converter 9.1. An attacker must craft a malicious input containing precisely 264 bytes of padding data followed by carefully constructed values designed to overwrite CPU registers. This payload can be delivered through a specially crafted text file that the victim opens or imports into the application.

The exploitation technique involves:

1. Creating a payload with 264 bytes of padding to reach the stack boundary
2. Appending specific values to overwrite the saved return address
3. Optionally including shellcode or return-oriented programming (ROP) gadgets for code execution
4. Delivering the payload through the vulnerable 'Exit folder' input field

Technical details and proof-of-concept information can be found in the Exploit-DB #47788 advisory and the VulnCheck Advisory.

Detection Methods for CVE-2019-25331

Indicators of Compromise

• Unexpected crashes or abnormal termination of the AVS Audio Converter application
• Presence of unusually large text files or configurations associated with AVS Audio Converter
• Application error logs indicating stack corruption or access violations
• Evidence of code execution attempts following application crashes

Detection Strategies

• Monitor for AVS Audio Converter processes exhibiting abnormal behavior or unexpected child process spawning
• Implement endpoint detection rules to identify buffer overflow exploitation patterns
• Analyze crash dumps for evidence of stack smashing or register manipulation
• Use memory forensics to detect code injection attempts in AVS Audio Converter process space

Monitoring Recommendations

• Enable Windows Error Reporting to capture crash telemetry from AVS Audio Converter
• Deploy behavioral monitoring for file system access patterns related to AVS Audio Converter configuration files
• Implement application whitelisting to prevent execution of unauthorized code following exploitation
• Monitor for unusual process chains originating from AVS Audio Converter

How to Mitigate CVE-2019-25331

Immediate Actions Required

• Upgrade AVS Audio Converter to the latest available version from the AVS4YOU official website
• Restrict access to AVS Audio Converter on shared systems to trusted users only
• Implement application control policies to limit execution of potentially compromised applications
• Review system logs for any evidence of exploitation attempts

Patch Information

Users should check the AVS4YOU official website for the latest version of AVS Audio Converter that addresses this vulnerability. It is recommended to upgrade from version 9.1 to the most recent release available from the vendor.

Workarounds

• Avoid opening untrusted text files or configurations in AVS Audio Converter
• Implement Data Execution Prevention (DEP) and ASLR at the system level to mitigate exploitation
• Run AVS Audio Converter with reduced privileges when possible
• Consider using alternative audio conversion software until a patched version is confirmed

# Enable DEP for all programs (Windows)
bcdedit /set nx AlwaysOn

# Verify DEP status
wmic OS Get DataExecutionPrevention_SupportPolicy