CVE-2019-25547: Spytech-web Netaware Buffer Overflow Flaw

CVE-2019-25547 Overview

CVE-2019-25547 is a buffer overflow vulnerability affecting NetAware 1.20, a web filtering application developed by Spytech-web. The vulnerability exists in the User Blocking feature and allows local attackers to crash the application by supplying oversized input. Specifically, attackers can paste a malicious buffer of 512 bytes into the "Add a website or keyword to be filtered" field and trigger a denial of service condition when attempting to remove the created block.

This vulnerability is classified as CWE-787 (Out-of-bounds Write), indicating that the application fails to properly validate input length before writing data to memory, resulting in memory corruption that leads to application instability.

Critical Impact

Local attackers can exploit this buffer overflow to cause a denial of service by crashing the NetAware application, potentially disrupting web filtering and monitoring capabilities on affected systems.

Affected Products

• Spytech-web NetAware version 1.20
• NetAware User Blocking feature component

Discovery Timeline

• 2026-03-21 - CVE-2019-25547 published to NVD
• 2026-03-23 - Last updated in NVD database

Technical Details for CVE-2019-25547

Vulnerability Analysis

This buffer overflow vulnerability stems from improper bounds checking in NetAware's User Blocking feature. When a user adds a website or keyword to be filtered, the application allocates a fixed-size buffer to store the input. The vulnerability manifests when an attacker provides input exceeding the expected buffer size—specifically, 512 bytes or more.

The attack requires local access to the system running NetAware. The exploitation process involves two steps: first, pasting the oversized buffer into the filter input field, and second, triggering the crash by attempting to remove the malicious block entry. This two-step process suggests the vulnerability occurs during the block removal operation rather than during initial input processing.

Since this is a local attack vector with no authentication requirements, any user with access to the NetAware interface can trigger the vulnerability. The impact is limited to availability—there is no evidence of data confidentiality or integrity compromise.

Root Cause

The root cause is a classic buffer overflow condition (CWE-787: Out-of-bounds Write) in the User Blocking feature's input handling routine. The application fails to properly validate the length of user-supplied input before copying it to a fixed-size memory buffer. When the input exceeds the allocated buffer size of approximately 512 bytes, memory corruption occurs, leading to application instability and crash.

Attack Vector

The attack vector is local, requiring the attacker to have access to the NetAware application interface on the target system. The exploitation sequence is as follows:

1. The attacker opens the NetAware User Blocking feature
2. In the "Add a website or keyword to be filtered" field, the attacker pastes a crafted buffer of 512+ bytes
3. The malicious block entry is created and stored
4. When the attacker (or any user) attempts to remove this block entry, the application crashes due to memory corruption

This vulnerability does not require user interaction beyond the attacker's own actions, and no special privileges are needed to execute the attack. Technical details and proof-of-concept information can be found in the Exploit-DB #46908 entry and the VulnCheck Advisory.

Detection Methods for CVE-2019-25547

Indicators of Compromise

• Unexpected crashes of the NetAware application, particularly when managing blocked websites or keywords
• Presence of unusually long entries (512+ bytes) in the NetAware blocking configuration
• Application error logs or Windows Event Viewer entries indicating access violations or buffer overrun exceptions in NetAware processes
• Repeated NetAware service restarts without clear cause

Detection Strategies

• Monitor for abnormal input lengths in NetAware configuration fields exceeding 500 characters
• Implement application crash monitoring for NetAware processes using endpoint detection tools
• Review Windows Event Logs for application faults associated with NetAware executables
• Deploy SentinelOne Singularity to detect and alert on process crashes indicative of exploitation attempts

Monitoring Recommendations

• Enable verbose logging on systems running NetAware to capture application behavior and potential crash events
• Configure endpoint protection solutions to monitor for signs of buffer overflow exploitation attempts
• Establish baseline metrics for NetAware stability and alert on deviations
• Consider implementing application whitelisting to prevent unauthorized modifications to NetAware configurations

How to Mitigate CVE-2019-25547

Immediate Actions Required

• Inventory all systems running NetAware version 1.20 and assess exposure risk
• Restrict local access to NetAware administration interfaces to trusted users only
• Implement user access controls to limit who can modify blocking configurations
• Consider replacing NetAware with an alternative web filtering solution if a patch is not available
• Deploy SentinelOne Singularity Platform for enhanced endpoint protection and crash detection

Patch Information

At the time of this advisory, no official patch information has been published by Spytech-web for CVE-2019-25547. Organizations should monitor vendor communications and the Infiltration Systems Homepage for updates. In the absence of an official patch, implementing the workarounds below is strongly recommended.

Workarounds

• Restrict access to the NetAware User Blocking feature to only trusted administrators
• Implement input validation at the network or application layer to reject oversized inputs before they reach NetAware
• Consider deploying NetAware in a sandboxed environment to limit the impact of crashes
• Evaluate alternative web filtering solutions that have undergone security hardening
• Implement monitoring to detect and recover from application crashes automatically

# Configuration example - Restrict access to NetAware configuration
# Limit local user permissions on Windows systems

# Review and restrict NTFS permissions on NetAware installation directory
icacls "C:\Program Files\NetAware" /inheritance:r
icacls "C:\Program Files\NetAware" /grant:r Administrators:(OI)(CI)F
icacls "C:\Program Files\NetAware" /grant:r SYSTEM:(OI)(CI)F

# Monitor for NetAware crashes using Windows Event Log
# Create a scheduled task to alert on Application Error events for NetAware
wevtutil qe Application /q:"*[System[Provider[@Name='Application Error']]]" /f:text