Lumma Stealer: The.PIF File Path Execution and Data Theft

Lumma Stealer is a sophisticated information-stealing malware that primarily targets credentials, browser data, and system information. One of the key components used by Lumma for execution and persistence is a .pif (Program Information File) file, often disguised as a legitimate Windows shortcut or executable. This report provides an in-depth analysis of how Lumma utilizes .pif files and the steps necessary for complete removal and mitigation.

Understanding.PIF Files in Lumma Stealer

What is a.PIF file?

• .pif(Program Information File) was originally used in Windows to store settings for MS-DOS applications.
• Cybercriminals exploit .pif extensions because modern Windows systems still recognize them as executable files.
• They can act as droppers, loaders, or disguises for malware like Lumma Stealer.

How Lumma Stealer Uses. PIF Files

• Malware Execution: The .pif file serves as a dropper, launching the malicious payload when executed.
• Code Injection: The .pif file may inject itself into legitimate system processes (explorer.exe,svchost.exe) to avoid detection.
• Persistence Mechanism: Lumma may modify registry keys, create scheduled tasks, or place .pif files in startup locations to ensure it runs after reboots.
• Data Exfiltration: Once executed, it steals credentials, cookies, and system information before sending them to a remote C2 server.
• Self-Deletion: Some versions of Lumma automatically delete the .pif file after execution to avoid forensic investigation.

Infection Pathways & Execution Flow

Step 1: Initial Execution

• The user unknowingly downloads and executes Write.pif.
• The .pif file loads the Lumma payload (possibly a .dll or .exe file).

Step 2: Process Injection & Evasion

• The .pif file executes shellcode that injects malware into legitimate Windows processes.
• Commonly injected processes: explorer.exe, svchost.exe, chrome.exe.
• Uses encrypted communication to contact the Command & Control (C2) server.

Step 3: Credential & Data Theft

• Extracts browser-stored passwords, cookies, and autofill data.
• Monitors clipboards for cryptocurrency wallets.
• Captures system details (OS, IP, hardware info).

Step 4: Exfiltration

• Sends stolen data to C2 via Telegram bots, darknet servers, or compromised domains.
• Uses .txt or .log files (e.g., autofill.txt) to temporarily store stolen credentials before transmission.

Step 5: Persistence & Further Actions

• Registers itself in HKCU\Software\Microsoft\Windows\CurrentVersion\Run.
• Creates scheduled tasks or startup entries.
• Can download additional malware or self-delete to erase traces.

How to Remove Lumma .PIF File & Malware

Step 1: Isolate the Infected System

• Disconnect the device from the internet to prevent data exfiltration.
• Boot into Safe Mode with Networking (Press F8 while booting → Select Safe Mode with Networking).

Step 2: Terminate Malicious Processes

• Open Task Manager (Ctrl + Shift + Esc)
• Look for suspicious processes (Write.pif, explorer.exe with high CPU usage).
• Run the following command in PowerShell:

        Stop-Process -Name "Write.pif" -Force

taskkill /F /IM explorer.exe

Step 3: Delete the Malware Files

• Navigate to the directory: C:\Users\user\AppData\Local\Temp\777406\
• Delete Write.pif and any suspicious .exe, .dll, or .bat files.
• Delete the write.ipf file from C:\.

Step 4: Remove Persistence Mechanisms

• Check Startup Entries:

Get-ItemProperty -Path "HKCU:\Software\Microsoft\Windows\CurrentVersion\Run"

If you find any unknown entries, remove them:

Remove-Item -Path "HKCU:\Software\Microsoft\Windows\CurrentVersion\Run\Write.pif" -Force

• Check Scheduled Tasks:

Get-ScheduledTask | Where-Object {$_.TaskName -like "*Lumma*"}

If found, delete:

Unregister-ScheduledTask -TaskName "LummaStealer" -Confirm:$false

Step 5: Scan for Malware & Clean System

• Run a full system scan with:
  • Windows Defender: Start-MpScan -ScanType FullScan
  • Malwarebytes or ESET for deeper detection.
• Use Autoruns (from Sysinternals) to check hidden startup entries.
• Monitor network traffic with Wireshark to ensure no C2 communication.

Preventive Measures

• Enable MFA for accounts to mitigate stolen credentials.
• Disable execution of .pif files via Group Policy:

New-ItemProperty -Path "HKLM:\Software\Microsoft\Windows\CurrentVersion\Policies\Explorer" -Name "DisallowPIF" -Value 1 -PropertyType DWord -Force

• Educate users on phishing and malware risks.
• Use EDR Solutions.

The .pif file is a critical component in Lumma Stealer’s execution chain. It serves as a stealthy dropper, allowing malware to persist and exfiltrate sensitive data. Identifying and removing .pif files, along with other artifacts like write.ipf, is essential to mitigating the Lumma Stealer infection. A multi-layered approach involving endpoint security, network monitoring, and user awareness is necessary to prevent reinfection and protect sensitive data.