CVE-2021-47818 Overview
CVE-2021-47818 is a denial of service vulnerability affecting DupTerminator version 1.4.5639.37199. The vulnerability allows attackers to crash the application by inputting a long character string in the Excluded text box. Specifically, attackers can generate a payload of 8000 repeated characters to trigger the application to stop working on Windows 10 systems.
This vulnerability is classified as CWE-1284 (Improper Validation of Specified Quantity in Input), indicating the application fails to properly validate the size or length of input data before processing it.
Critical Impact
Local attackers can cause the DupTerminator application to crash by submitting an oversized input string, resulting in denial of service and disruption of file management operations.
Affected Products
- DupTerminator version 1.4.5639.37199
- Windows 10 systems running affected DupTerminator version
Discovery Timeline
- 2026-01-16 - CVE-2021-47818 published to NVD
- 2026-01-16 - Last updated in NVD database
Technical Details for CVE-2021-47818
Vulnerability Analysis
The vulnerability stems from improper input validation in the DupTerminator application's Excluded text box field. When a user enters an excessively long character string (approximately 8000 characters), the application fails to handle this input gracefully, resulting in an application crash.
This is a local attack vector vulnerability, meaning an attacker must have local access to the system to exploit it. The attack requires user interaction, as the malicious input must be entered into the application's interface. While the impact is limited to application availability (denial of service), it can disrupt users who rely on DupTerminator for duplicate file detection and management.
Root Cause
The root cause is classified as CWE-1284: Improper Validation of Specified Quantity in Input. The application does not implement proper bounds checking on the length of text input in the Excluded text box. When an input exceeding the expected buffer size is provided, the application cannot process it correctly, leading to an unhandled exception and subsequent crash.
Attack Vector
The attack vector is local, requiring direct access to the DupTerminator application interface. An attacker would need to:
- Open the DupTerminator application on the target system
- Navigate to the Excluded text box field
- Input approximately 8000 repeated characters
- Trigger the application to process the input
The attack results in the application becoming unresponsive and ultimately crashing on Windows 10 systems. While the vulnerability does not allow for code execution or data exfiltration, it can be used to disrupt legitimate user operations.
Technical details and proof-of-concept information can be found in the Exploit-DB #49917 advisory. The vulnerability mechanism involves overwhelming the input handling routine with an unexpectedly large string, causing the application to fail during processing.
Detection Methods for CVE-2021-47818
Indicators of Compromise
- Application crash events for DupTerminator in Windows Event Logs
- Unusual application termination or "not responding" states for DupTerminator
- Windows Error Reporting (WER) crash dumps related to DupTerminator executable
Detection Strategies
- Monitor Windows Application Event Logs for DupTerminator crash events (Event ID 1000, 1001)
- Implement endpoint detection rules for unexpected termination of DupTerminator.exe
- Review system stability reports for recurring application failures
Monitoring Recommendations
- Configure Windows Error Reporting to capture crash dumps for forensic analysis
- Set up alerts for repeated application crashes that may indicate exploitation attempts
- Monitor file system activity for evidence of DoS attack preparation scripts
How to Mitigate CVE-2021-47818
Immediate Actions Required
- Restrict access to DupTerminator to trusted users only
- Consider removing or disabling DupTerminator until a patched version is available
- Implement application whitelisting to prevent unauthorized script execution that could automate the attack
- Monitor for abnormal application behavior and crashes
Patch Information
No official patch information is currently available for this vulnerability. Users should monitor the SourceForge Project Page for updates from the developer. Consider using alternative duplicate file detection tools until a fix is released.
For additional security context, refer to the VulnCheck Advisory.
Workarounds
- Limit the use of DupTerminator to controlled environments with trusted users
- Consider using alternative duplicate file management utilities that are actively maintained
- Implement operating system-level input validation or application sandboxing where possible
- Restrict local access to systems where DupTerminator is installed
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
