CVE-2021-47797: Leawo Prof. Media DoS Vulnerability

CVE-2021-47797 Overview

CVE-2021-47797 is a buffer overflow vulnerability (CWE-120) in Leawo Prof. Media version 11.0.0.1 that enables attackers to trigger a denial of service condition. The vulnerability exists in the application's registration interface where the activation keycode field fails to properly validate input length, allowing attackers to crash the application by supplying an oversized payload.

Critical Impact

Attackers can crash the Leawo Prof. Media application by pasting a specially crafted 6000-byte buffer of repeated characters into the registration interface, causing complete application unavailability.

Affected Products

• Leawo Prof. Media 11.0.0.1

Discovery Timeline

• 2026-01-16 - CVE-2021-47797 published to NVD
• 2026-01-16 - Last updated in NVD database

Technical Details for CVE-2021-47797

Vulnerability Analysis

This vulnerability falls under CWE-120 (Buffer Copy without Checking Size of Input), a classic buffer overflow condition. The Leawo Prof. Media application fails to implement proper bounds checking on the activation keycode input field within its registration interface. When a user or attacker supplies an input exceeding the expected buffer size, the application attempts to copy the entire payload into a fixed-size memory buffer, resulting in memory corruption and subsequent application crash.

The attack requires local access and user interaction, as the malicious payload must be pasted directly into the application's registration dialog. While this limits the attack surface, it still presents a viable denial of service vector in scenarios where users may unknowingly paste malicious content or where shared workstations are involved.

Root Cause

The root cause of CVE-2021-47797 is improper input validation in the activation keycode field handling routine. The application allocates a fixed-size buffer for the keycode input but fails to verify that incoming data does not exceed this allocation before performing the copy operation. This missing bounds check allows an attacker-controlled buffer of approximately 6000 bytes to overflow the intended memory region, corrupting adjacent memory structures and triggering an unhandled exception that crashes the application.

Attack Vector

The attack vector for this vulnerability is local, requiring an attacker to have access to the target system where Leawo Prof. Media is installed. The exploitation process involves:

1. Generating a malicious payload consisting of approximately 6000 bytes of repeated characters
2. Launching the Leawo Prof. Media application on the target system
3. Navigating to the registration or activation interface
4. Pasting the oversized payload into the activation keycode field
5. The application processes the input without proper bounds checking, causing a buffer overflow and immediate crash

The vulnerability can be reproduced by crafting a buffer of repeated characters (such as 6000 'A' characters) and inputting this string into the registration dialog. Technical details and proof-of-concept information are available in the Exploit-DB #50153 entry and the VulnCheck Advisory.

Detection Methods for CVE-2021-47797

Indicators of Compromise

• Unexpected crashes of the Leawo Prof. Media application, particularly during registration attempts
• Application event logs showing unhandled exceptions or access violations in Leawo Prof. Media.exe
• Presence of crash dump files indicating buffer overflow or memory corruption in the application process

Detection Strategies

• Monitor Windows Event Logs for application crashes related to Leawo Prof. Media with fault module addresses indicating buffer overflows
• Implement endpoint detection rules to alert on repeated application crashes that may indicate active exploitation attempts
• Deploy application whitelisting policies that prevent unauthorized input automation tools from interacting with the registration interface

Monitoring Recommendations

• Configure SentinelOne agents to monitor for suspicious process behavior and application crashes related to Leawo Prof. Media
• Enable Windows Error Reporting collection to capture crash dump data for forensic analysis
• Establish baselines for normal application behavior to identify anomalous crash patterns

How to Mitigate CVE-2021-47797

Immediate Actions Required

• Restrict access to the Leawo Prof. Media registration interface to authorized administrators only
• Consider temporary removal or disabling of Leawo Prof. Media on critical systems until a patch is available
• Educate users about the risks of pasting untrusted content into application input fields
• Deploy endpoint protection solutions capable of detecting and preventing buffer overflow exploitation

Patch Information

At the time of publication, no official patch has been confirmed for this vulnerability. Users should check the Leawo Official Website for security updates and newer versions that may address this issue. Upgrading to the latest available version of Leawo Prof. Media is recommended when a patched release becomes available.

Workarounds

• Limit user access to the Leawo Prof. Media registration functionality through application control policies
• Implement input filtering at the clipboard level using endpoint security tools to detect and block oversized paste operations
• Deploy the application in an isolated environment or sandbox to contain potential denial of service impacts
• Consider using alternative software solutions if the application is non-essential and no patch is forthcoming