CVE-2019-25318: AVS Audio Converter Buffer Overflow Flaw

CVE-2019-25318 Overview

CVE-2019-25318 is a stack overflow vulnerability affecting AVS Audio Converter version 9.1.2.600. This vulnerability allows attackers to execute arbitrary code by manipulating the output folder text input field within the application. When a user interacts with the 'Browse' button after a malicious payload has been crafted in the output folder field, the application's stack memory can be overwritten, potentially triggering a bind shell on port 9999.

Critical Impact

Successful exploitation of this stack overflow vulnerability enables attackers to achieve arbitrary code execution on the target system, potentially establishing persistent remote access through a bind shell.

Affected Products

• AVS Audio Converter 9.1.2.600

Discovery Timeline

• 2026-02-12 - CVE-2019-25318 published to NVD
• 2026-02-12 - Last updated in NVD database

Technical Details for CVE-2019-25318

Vulnerability Analysis

This vulnerability is classified as CWE-121 (Stack-based Buffer Overflow). The stack overflow occurs when the application fails to properly validate the length of user-supplied input in the output folder text field. When an attacker supplies an overly long or specially crafted string, it exceeds the allocated buffer size on the stack, allowing adjacent memory to be overwritten.

The local attack vector requires user interaction—specifically, the victim must click the 'Browse' button after the malicious input has been entered. This user interaction requirement is notable, but social engineering techniques or malicious document automation could potentially trigger the vulnerable code path.

Root Cause

The root cause of CVE-2019-25318 lies in insufficient bounds checking on the output folder text input field within AVS Audio Converter. The application allocates a fixed-size buffer on the stack to hold the folder path string but does not enforce length restrictions on user input. When the input exceeds this buffer's capacity, the excess data overwrites adjacent stack memory, including the return address and other critical stack frames.

Attack Vector

The attack requires local access to the system where AVS Audio Converter is installed. The attacker must either:

1. Directly manipulate the output folder text field with a crafted payload
2. Convince a user to paste or enter the malicious input
3. Potentially leverage another vulnerability to inject the malicious string programmatically

When the 'Browse' button is clicked, the overflow is triggered, and carefully crafted shellcode can redirect execution to establish a bind shell listener on port 9999. The attacker can then connect to this port to gain command execution on the compromised system.

Technical details and proof-of-concept exploits are available through Exploit-DB #47788 and Exploit-DB #47810. Additional advisory information can be found at the VulnCheck Advisory on AVS Audio Converter.

Detection Methods for CVE-2019-25318

Indicators of Compromise

• Unexpected network listeners on port 9999 or other non-standard ports on systems running AVS Audio Converter
• Unusual child processes spawned from the AVS Audio Converter application process
• Abnormal memory access patterns or application crashes in AVS Audio Converter

Detection Strategies

• Monitor for bind shell activity on port 9999 or unusual outbound connections from desktop multimedia applications
• Implement endpoint detection rules to identify stack pivot or ROP chain execution patterns
• Deploy application control policies to detect unexpected behavior from AVSAudioConverter.exe

Monitoring Recommendations

• Enable Windows Event Logging for process creation events (Event ID 4688) to track processes spawned by AVS Audio Converter
• Configure network monitoring to alert on any listening ports opened by desktop applications
• Implement file integrity monitoring on AVS Audio Converter installation directories

How to Mitigate CVE-2019-25318

Immediate Actions Required

• Remove or disable AVS Audio Converter 9.1.2.600 from systems until a patch is available
• Restrict user permissions to prevent installation of unpatched multimedia applications
• Implement application whitelisting to block unauthorized application execution

Patch Information

No vendor patch information is currently available in the CVE data. Users should check the AVS4You Homepage for any updated versions that may address this vulnerability. Consider upgrading to a newer version of the software if one exists that resolves this issue.

Workarounds

• Uninstall or disable AVS Audio Converter 9.1.2.600 until a patched version is released
• Use alternative audio conversion software that is actively maintained and patched
• Implement network segmentation to limit the impact of potential bind shell exploitation
• Block outbound and inbound connections on port 9999 at the host firewall level

# Block port 9999 on Windows Firewall (run as Administrator)
netsh advfirewall firewall add rule name="Block CVE-2019-25318 Bind Shell" dir=in action=block protocol=tcp localport=9999
netsh advfirewall firewall add rule name="Block CVE-2019-25318 Outbound" dir=out action=block protocol=tcp remoteport=9999