CVE-2019-25564: Uvnc Pchelpwarev2 DOS Vulnerability

CVE-2019-25564 Overview

CVE-2019-25564 is a denial of service vulnerability affecting PCHelpWareV2 version 1.0.0.5. The vulnerability allows local attackers to crash the application by supplying an excessively long string in the Group field. This buffer overflow condition occurs when an attacker pastes an oversized payload into the Group property field and clicks Ok, triggering an application crash.

Critical Impact

Local attackers can cause application crashes through buffer overflow in the Group field, resulting in denial of service conditions that disrupt remote support operations.

Affected Products

• UVNC PCHelpWareV2 1.0.0.5

Discovery Timeline

• 2026-03-21 - CVE-2019-25564 published to NVD
• 2026-03-24 - Last updated in NVD database

Technical Details for CVE-2019-25564

Vulnerability Analysis

This vulnerability is classified as CWE-787 (Out-of-bounds Write), a memory corruption issue that occurs when the application writes data past the end of the intended buffer. PCHelpWareV2 fails to properly validate the length of user-supplied input in the Group field before copying it to a fixed-size buffer in memory. When an attacker provides a string that exceeds the allocated buffer size, the application writes beyond the buffer boundaries, corrupting adjacent memory and causing the application to crash.

The attack requires local access and user interaction—specifically, an attacker must have the ability to input data into the Group field of the application interface. While this limits the attack surface compared to remotely exploitable vulnerabilities, the local attack vector makes it relevant in scenarios where multiple users share access to a system or where an attacker has limited local access and wants to disrupt operations.

Root Cause

The root cause of this vulnerability is improper input validation in the Group field handler. The application does not implement adequate boundary checks before processing user-supplied strings, allowing oversized input to overflow the allocated buffer. This is a classic buffer overflow condition where the application assumes input will not exceed a certain length without enforcing that constraint programmatically.

Attack Vector

The attack is executed locally and requires user interaction. An attacker must:

1. Access the PCHelpWareV2 application interface
2. Navigate to the Group field settings
3. Paste or input an excessively long string into the Group property field
4. Click the Ok button to submit the malformed input

The application then attempts to process the oversized string, triggering the buffer overflow and causing an immediate application crash. Technical details about the specific exploitation technique can be found in the Exploit-DB #46709 entry, which documents the denial of service condition.

Detection Methods for CVE-2019-25564

Indicators of Compromise

• Application crash events or unexpected termination of PCHelpWareV2.exe
• Windows Error Reporting entries related to PCHelpWareV2 with access violation exceptions
• Suspicious user activity involving repeated access to Group field configuration settings

Detection Strategies

• Monitor Windows Event Logs for application crash events (Event ID 1000) involving PCHelpWareV2
• Deploy endpoint detection rules to alert on abnormal application terminations
• Implement file integrity monitoring on PCHelpWareV2 configuration files for unexpected modifications

Monitoring Recommendations

• Enable application crash logging and configure alerts for PCHelpWareV2 process terminations
• Monitor for patterns of repeated application restarts that may indicate active exploitation attempts
• Review user activity logs for access patterns involving the Group field configuration

How to Mitigate CVE-2019-25564

Immediate Actions Required

• Restrict local access to systems running PCHelpWareV2 to trusted users only
• Consider removing or replacing PCHelpWareV2 if it is not essential to operations
• Implement application whitelisting to control which users can execute the application
• Monitor for updated versions from the vendor that may address this vulnerability

Patch Information

No vendor advisory or specific patch information is available for this vulnerability at this time. Organizations should monitor the UVNC Homepage and the Vulncheck Advisory for updates regarding security fixes.

Workarounds

• Restrict physical and remote access to systems where PCHelpWareV2 is installed
• Implement the principle of least privilege to limit which users can configure application settings
• Consider deploying alternative remote support tools that are actively maintained and receive security updates
• Use application control policies to prevent unauthorized users from accessing PCHelpWareV2 configuration interfaces

# Restrict application access (Windows example)
# Limit execution permissions to specific user groups
icacls "C:\Program Files\PCHelpWareV2\PCHelpWareV2.exe" /inheritance:r
icacls "C:\Program Files\PCHelpWareV2\PCHelpWareV2.exe" /grant:r "DOMAIN\TrustedAdmins:(RX)"