Open Task Manager (Ctrl + Shift + Esc), find net5system.exe, right-click it, and select “Open file location”.
| Location | Risk Level |
| --- | --- |
| C:\Windows\System32\ | Very suspicious (almost always malware impersonating a system file) |
| C:\Windows\SysWOW64\ | Very suspicious |
| C:\Program Files\ or C:\Program Files (x86)\ | Moderately suspicious – check publisher |
| C:\Users\[YourName]\AppData\Local\Temp\ | Highly suspicious – temporary folders shouldn’t run persistent processes |
| C:\Users\[YourName]\AppData\Roaming\ | Highly suspicious – common for malware persistence |
| C:\ProgramData\ | Suspicious – often used by adware |
Adware bundled with free software (like fake PDF creators, download managers, or streaming tools) often drops net5system.exe into the %AppData% or %LocalAppData% folder. Once running, it injects ads into your browser, redirects search queries, and tracks browsing habits. net5system.exe
Tell-tale signs: Pop-up ads on your desktop, new browser toolbars, and your default search engine changing to something like “SearchWeb” or “Yahoo-redirect”.
| Attribute | Details |
|-----------|---------|
| File name | net5system.exe |
| Typical location | %TEMP%, %APPDATA%, %PROGRAMDATA%, or random subfolders |
| Legitimate counterpart | None – no Microsoft signed binary uses this exact name |
| Common masquerade | Pretends to be .NET 5 system service | Open Task Manager ( Ctrl + Shift + Esc ), find net5system
The name appears designed to blend in with legitimate .NET-related processes (e.g., mscorsvw.exe, dotnet.exe). This social engineering targets administrators scanning task lists quickly.
rule net5system_malware
meta:
description = "Detects known net5system.exe malicious samples"
author = "Security Research"
strings:
$s1 = "net5system" nocase
$s2 = "XMRig" ascii wide
$s3 = "pool.supportxmr" ascii
$s4 = "miner.exe" ascii
condition:
(filesize < 2MB) and (1 of ($s2,$s3,$s4)) and filename == "net5system.exe"
Adware often leaves behind extensions or policies. Reset Chrome/Edge/Firefox to default, remove unfamiliar extensions, and clear cached data. Adware often leaves behind extensions or policies
net5system.exe is a legitimate executable file associated with NET5 - Network Management System, a software suite developed by ASIX s.r.o. (a Czech company specializing in network auditing, inventory, and management tools). Under normal circumstances, this file is safe and operates as part of an IT administration or hardware inventory system. However, due to its name and background execution behavior, it can occasionally be mistaken for malware, spoofed by malicious software, or cause performance issues if misconfigured.
| Detail | Value | |--------|-------| | Typical file size | Between 500 KB – 2 MB | | Digital signer | ASIX s.r.o. | | Original filename | net5system.exe (as per PE header) | | Product version | Varies (e.g., 5.0.0.x, 5.1.x.x) | | Entry type | Windows service (Win32OwnProcess) |