PayForRepair Ransomware (.P4R Files) Analysis and Removal Guide

PayForRepair (also known as .P4R) is a dangerous file-encrypting ransomware belonging to the Dharma ransomware family. This malware targets Windows systems, encrypting user files with strong cryptography and appending them with .P4R extension. After encryption, it demands payment in Bitcoin cryptocurrency for decryption services. PayForRepair is primarily distributed through vulnerable RDP (Remote Desktop Protocol) services and phishing campaigns. This analysis examines the ransomware’s technical features, encryption methods, distribution tactics, and provides guidance for removal and potential recovery options.

Introduction to PayForRepair Ransomware

PayForRepair is a file-encrypting ransomware that belongs to the notorious Dharma ransomware family. First detected in April 2025, this malware targets Windows systems, encrypting personal files and demanding ransom for their recovery. The ransomware gets its name from the .P4R extension it appends to encrypted files and its ransom demand messages instructing victims to “pay for repair” of their files.

Like other Dharma variants, PayForRepair is designed to encrypt a wide range of user files while avoiding system files to ensure the computer remains operational for ransom payment. After encryption, the malware creates ransom notes in two forms: a pop-up window and text files named “info.txt” placed in each encrypted directory.

What makes PayForRepair particularly dangerous is its use of strong encryption algorithms that make decryption without the attackers’ key virtually impossible. According to analysis by PCRisk researchers, the ransomware also employs techniques to ensure persistence on infected systems and prevents recovery by deleting Volume Shadow Copies.

Technical Analysis of PayForRepair Ransomware

PayForRepair functions as a standard file-encrypting ransomware with several technical features characteristic of the Dharma ransomware family. Understanding these technical aspects helps explain how the malware operates and its impact on infected systems.

Encryption Process

When PayForRepair infects a system, it performs the following actions:

1. File scanning: The ransomware scans the system for target files, focusing on user-created documents, images, videos, and other personal data
2. Process termination: It terminates processes associated with opened files (like database programs and file readers) to ensure they can be encrypted
3. Encryption: Files are encrypted using a combination of symmetric and asymmetric encryption algorithms
4. Renaming: Encrypted files are renamed with the original name plus a unique victim ID, the attackers’ email address, and the .P4R extension (e.g., “document.docx” becomes “document.docx.id-9ECFA84E.[payforrepair@tuta.io].P4R”)
5. Ransom note creation: A pop-up window appears and text files named “info.txt” are created in each directory with encrypted files
6. Shadow copy deletion: The malware deletes Volume Shadow Copies to prevent easy recovery of files

Persistence Mechanisms

PayForRepair ensures its persistence on infected systems by:

• Copying the malware to the %LOCALAPPDATA% directory
• Creating registry entries in the Run keys to execute at system startup
• Modifying Windows settings to auto-start upon each system reboot
• Disabling the Windows Firewall to prevent security measures from blocking its activities

Targeted File Types

PayForRepair targets a wide range of file types including but not limited to:

• Documents: .doc, .docx, .xls, .xlsx, .ppt, .pptx, .pdf, .txt, .rtf
• Images: .jpg, .jpeg, .png, .bmp, .gif, .tiff, .psd
• Videos: .mp4, .mov, .avi, .mkv, .flv
• Audio: .mp3, .wav, .wma, .flac, .aac
• Archives: .zip, .rar, .7z, .tar, .gz
• Databases: .sql, .accdb, .mdb, .dbf, .odb
• Programming: .php, .html, .js, .css, .java, .py, .c, .cpp
• Other: .pst, .ost, .eml, .msg (email files)

Ransom Demands and Communication

After encrypting files, PayForRepair creates ransom notes to instruct victims on how to contact the attackers and potentially recover their files. These notes appear in two forms: a pop-up window that appears on screen and text files named “info.txt” placed in each directory with encrypted files.

Ransom Note Content

The text file (“info.txt”) is brief and simply informs victims that their data has been locked, instructing them to email the attackers for recovery information. The pop-up window contains more detailed information, stating:

• All files have been encrypted
• Decryption requires payment in Bitcoin cryptocurrency
• Victims can test the decryption process on three files (with certain limitations)
• Warning against using third-party recovery tools or modifying encrypted files
• Contact information for the attackers (payforrepair@tuta.io, payforrepair@mailum.com)

The attackers typically demand varying amounts based on the victim profile, with ransoms generally ranging from several hundred to several thousand dollars in Bitcoin. They may offer to decrypt a few files for free as “proof” they can restore the data, but this doesn’t guarantee they will provide the decryption tool after payment.

Payment Process

If a victim contacts the attackers, they typically receive instructions to:

1. Send a specific identifier showing which files were encrypted
2. Receive a Bitcoin wallet address for payment
3. Make the payment in Bitcoin cryptocurrency
4. Send confirmation of the transaction
5. Supposedly receive a decryption tool after payment verification

Important warning: Security experts, including those at Trojan Killer, strongly advise against paying the ransom. There is no guarantee that cybercriminals will provide working decryption tools after payment, and doing so funds further criminal activities.

Distribution Methods

PayForRepair ransomware is distributed through several methods, with vulnerable RDP services being the primary vector. Understanding these distribution channels is crucial for implementing effective preventive measures.

RDP Attacks

The primary distribution method for PayForRepair and other Dharma variants is through vulnerable Remote Desktop Protocol (RDP) services. Attackers use:

• Brute-force attacks: Systematically attempting various password combinations until finding the correct one
• Dictionary attacks: Using lists of commonly used passwords to gain unauthorized access
• Credential stuffing: Using leaked username/password combinations from other data breaches

Systems with weak RDP credentials, exposed RDP ports (3389), or outdated RDP services are particularly vulnerable to these attacks. Once access is gained, attackers manually deploy the ransomware on the compromised system.

Phishing Campaigns

While RDP attacks are the primary vector, PayForRepair may also be distributed through phishing campaigns, similar to other ransomware families. These attacks typically involve:

• Malicious email attachments: Disguised as invoices, shipping notices, or other business documents
• Malicious links: Leading to websites that exploit browser vulnerabilities or trick users into downloading malware
• Social engineering tactics: Creating a sense of urgency or importance to trick users into opening attachments or clicking links

Phishing emails related to PayForRepair often mimic legitimate business communications, similar to those seen in the We Hacked Your System email scam or the Server (IMAP) Session Authentication scam.

Other Distribution Methods

Additional distribution methods that may be used include:

• Malvertising: Malicious advertisements that redirect to exploit kits
• Drive-by downloads: Automatic downloads that occur when visiting compromised websites
• Trojan droppers: Malware that appears legitimate but installs ransomware in the background
• Cracked software: Pirated software that contains hidden malware, similar to threats found in cracks and keygens
• Supply chain attacks: Compromising trusted software distribution channels to deliver malware

Technical Indicators of Compromise (IOCs)

For cybersecurity specialists and incident responders, identifying PayForRepair ransomware infections requires attention to specific technical indicators. These IOCs can be used in security monitoring systems, SIEM platforms, and threat hunting activities.

File System Artifacts

The PayForRepair ransomware typically creates or modifies the following files:

• Malware executable: Typically dropped in %LOCALAPPDATA% with random or system-like names (e.g., svchost.exe, msupdate.exe)
• Ransom notes: “info.txt” files in encrypted directories
• Encrypted files: Original files with “.id-[UNIQUE_ID].[payforrepair@tuta.io].P4R” appended
• Temporary files: Created during encryption in %TEMP% directory
• Configuration files: May contain encryption keys and victim identifiers

Registry Indicators

PayForRepair establishes persistence and stores configuration data in the following registry locations:

Network-based Indicators

While PayForRepair typically doesn’t require C2 (Command and Control) communication for its core encryption functionality, some variants may exhibit the following network behaviors:

• IP beacon: May connect to attacker-controlled servers to report successful infections
• Key exchange: Some variants download encryption keys from remote servers
• Domain generation: Advanced variants may use domain generation algorithms (DGA) for command and control

Process and Command Line Indicators

The following process behaviors are commonly associated with PayForRepair infection:

• Process injection: The malware may inject code into legitimate Windows processes
• Shadow copy deletion: Command lines containing vssadmin delete shadows or wmic shadowcopy delete
• Stopped services: Attempts to disable security services such as Windows Defender and backup services
• PowerShell commands: May use obfuscated PowerShell for privilege escalation or additional payload execution

Sample File Hashes

The following are sample file hashes associated with PayForRepair ransomware variants (based on public threat intelligence):

MITRE ATT&CK Framework Mapping

PayForRepair ransomware employs various techniques mapped to the MITRE ATT&CK framework. Understanding these tactics and techniques helps security professionals develop effective detection and mitigation strategies.

Tactic	Technique ID	Technique Name	Description
Initial Access	T1133	External Remote Services	Exploitation of publicly accessible RDP services with weak credentials
Initial Access	T1566	Phishing	Malicious email attachments in phishing campaigns
Execution	T1059.001	Command and Scripting Interpreter: PowerShell	Uses PowerShell to execute commands and encryption routines
Persistence	T1547.001	Boot or Logon Autostart Execution: Registry Run Keys	Establishes persistence through Windows registry run keys
Defense Evasion	T1562.001	Impair Defenses: Disable or Modify Tools	Disables Windows Defender and Windows Firewall
Defense Evasion	T1070.004	Indicator Removal: File Deletion	Deletes itself and logs after encryption
Credential Access	T1110	Brute Force	Uses brute force to compromise RDP credentials
Discovery	T1083	File and Directory Discovery	Enumerates files and directories for encryption
Discovery	T1082	System Information Discovery	Collects system information for victim identification
Collection	T1560	Archive Collected Data	May create archives of sensitive data
Impact	T1486	Data Encrypted for Impact	Encrypts user files to render them inaccessible
Impact	T1490	Inhibit System Recovery	Deletes Volume Shadow Copies to prevent recovery

Advanced Forensic Analysis

For forensic investigators and malware analysts, understanding the deeper technical aspects of PayForRepair ransomware is essential for incident response and threat hunting. This section outlines key forensic artifacts and analysis techniques.

Memory Forensics

Memory analysis of infected systems may reveal the following artifacts:

• Encryption keys: Potential recovery of encryption keys from memory dumps if captured during the encryption process
• Injected code: Evidence of code injection in legitimate Windows processes
• Command history: Traces of commands executed by the malware
• Network connections: Evidence of C2 communications

Tools like Volatility or Rekall can be used to analyze memory dumps from infected systems. Key Volatility plugins for PayForRepair analysis include:

Encryption Algorithm Analysis

PayForRepair uses a hybrid encryption approach typical of the Dharma family:

1. Symmetric encryption: Files are encrypted using AES-256 with a randomly generated key
2. Asymmetric encryption: The AES key is then encrypted using an RSA-2048 public key
3. Key storage: The encrypted AES key is stored either in the file header or in a separate file

The encryption process typically follows this pattern:

File headers of encrypted files may contain metadata, including the encrypted AES key and victim identifier, which helps attackers associate the files with specific victims.

YARA Rules for Detection

The following YARA rule can help detect PayForRepair ransomware variants:

Network Traffic Analysis

When analyzing network traffic related to PayForRepair infections, look for these patterns:

• RDP brute force attempts: Multiple failed RDP authentication attempts prior to infection
• C2 communication: HTTPS or HTTP traffic to unusual domains or IP addresses
• Data exfiltration: Unusual outbound transfers that may indicate stolen data
• DNS requests: Queries to newly registered or suspicious domains

Wireshark filters for detecting potential PayForRepair activity:

PayForRepair Ransomware Removal Instructions

Removing PayForRepair ransomware is crucial to prevent further encryption of files and to secure the system against additional malware. However, it’s important to note that removing the ransomware will not decrypt already encrypted files.

Manual Removal Steps

For advanced users who wish to manually remove PayForRepair ransomware:

1. Enter Safe Mode with Networking:
   • Restart your computer and press F8 repeatedly before Windows starts (for Windows 7 and earlier)
   • For Windows 8/10/11: Hold Shift while clicking Restart, then navigate to Troubleshoot → Advanced options → Startup Settings → Restart → Press 5 for Safe Mode with Networking
2. Terminate malicious processes:
   • Open Task Manager (Ctrl+Shift+Esc)
   • Look for suspicious processes (unfamiliar names or locations)
   • Select each suspicious process and click “End Task”
3. Delete malicious files:
   • Check the %LOCALAPPDATA% directory for recently added suspicious files
   • Delete any executables or files related to PayForRepair
4. Remove registry entries:
   • Open Registry Editor (type “regedit” in the Start menu)
   • Check the following locations for suspicious entries: HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Run
   • Delete any entries related to PayForRepair
5. Restart the computer in normal mode

Automated Removal Using Security Software

For most users, using reputable security software is the recommended approach:

1. Install reputable anti-malware software: If you don’t already have security software installed, download and install a trusted solution like Trojan Killer.
2. Update virus definitions: Ensure your security software has the latest virus definitions to detect PayForRepair.
3. Perform a full system scan: Run a complete scan of your system to detect and remove the ransomware and any associated malware.
4. Remove detected threats: Follow the security software’s instructions to quarantine or remove detected threats.
5. Restart your computer: After removal, restart your system to ensure all changes take effect.

File Recovery Options

Recovering files encrypted by PayForRepair ransomware is challenging since it uses strong encryption methods. However, there are several potential recovery options to explore before considering paying the ransom (which is not recommended).

Restore From Backups

The most reliable method for recovering encrypted files is to restore them from backups:

• External backups: Restore files from external hard drives, USB devices, or cloud storage services (OneDrive, Google Drive, Dropbox, etc.)
• System Restore: While System Restore won’t remove viruses directly, it might help recover some system files if restore points were created before the infection
• Email attachments: Check if copies of important files were sent as email attachments
• Cloud sync folders: If files were synchronized with cloud services, they might be recoverable from those services’ web interfaces

File Recovery Tools

If no backups are available, some data recovery tools might help retrieve files:

• Shadow Explorer: If the ransomware failed to delete all Volume Shadow Copies, this tool might help recover previous versions of files
• File recovery software: Programs designed to recover deleted files might recover some data if original files were deleted during encryption
• Previous version feature: Right-click on a file or folder, select Properties, and check the Previous Versions tab (effectiveness varies)

Note that these methods have limited effectiveness against modern ransomware like PayForRepair, which typically deletes shadow copies and thoroughly encrypts files.

Decryption Possibilities

While decryption without the attackers’ key is generally impossible, there are some resources to check:

• No More Ransom Project: Visit nomoreransom.org to check if decryption tools are available for this specific variant
• Security vendor releases: Major security companies occasionally release free decryptors when vulnerabilities are found in ransomware encryption
• Law enforcement breakthroughs: Sometimes law enforcement agencies seize servers containing decryption keys

For PayForRepair specifically, no free decryption tools were available at the time of this analysis. However, it’s worth periodically checking these resources as the situation may change.

Prevention Strategies

Preventing PayForRepair and similar ransomware infections requires a multi-layered security approach. Implementing these preventive measures can significantly reduce the risk of infection.

Secure Remote Desktop Protocol (RDP)

Since PayForRepair primarily spreads through RDP, securing this service is crucial:

• Use strong, complex passwords: Implement passwords with at least 12 characters including uppercase, lowercase, numbers, and special characters
• Enable account lockout policies: Lock accounts after multiple failed login attempts
• Implement multi-factor authentication (MFA): Require additional verification beyond passwords
• Use a VPN: Only allow RDP connections through a VPN
• Limit RDP access: Restrict RDP to only necessary user accounts
• Change the default RDP port (3389): Use a non-standard port to reduce automated scanning
• Use Network Level Authentication (NLA): Require user authentication before establishing a session

General Security Measures

Implement these general security practices to protect against all ransomware variants:

• Keep systems updated: Regularly install security updates for operating systems and applications
• Use reputable security software: Install and maintain anti-malware solutions with real-time protection
• Implement email filtering: Use solutions that scan attachments and links in emails
• Practice safe browsing: Avoid suspicious websites and downloading files from untrusted sources
• Disable macros: Don’t enable macros in documents from untrusted sources
• User awareness training: Educate users about phishing tactics and social engineering
• Application whitelisting: Allow only approved applications to run
• Network segmentation: Divide networks to contain potential breaches
• Regular security audits: Periodically test systems for vulnerabilities

Implement a Robust Backup Strategy

A comprehensive backup strategy is your best defense against ransomware:

• Follow the 3-2-1 rule: Keep at least three copies of your data, on two different storage types, with one copy stored offsite
• Regular backups: Schedule automatic backups of important data
• Offline backups: Keep some backups disconnected from the network
• Cloud backups: Use reputable cloud backup services with versioning
• Test restoration: Regularly verify that backups can be successfully restored
• Secured backup access: Protect backup systems with strong authentication

Services like Microsoft OneDrive offer features such as file versioning that can help recover from ransomware attacks, as they keep previous versions of files for up to 30 days. For more information on backup strategies, see our guide on how System Restore affects personal files.

Comparison with Other Ransomware

PayForRepair belongs to the Dharma ransomware family but has unique characteristics that distinguish it from other ransomware variants. Understanding these differences and similarities helps in recognizing the broader ransomware threat landscape.

Relation to Dharma Ransomware Family

As a Dharma variant, PayForRepair shares several characteristics with other members of this family:

• Similar encryption methodology using a combination of RSA and AES algorithms
• Similar file naming pattern (appending victim ID and contact information)
• Focus on RDP as the primary infection vector
• Targeting of both individual users and businesses
• Deletion of Volume Shadow Copies to prevent easy recovery

The Dharma family has been active since 2016 and continues to evolve with new variants like PayForRepair appearing regularly.

Comparison with Other Ransomware Families

Compared to other recent ransomware threats, PayForRepair has several distinctive features:

• Unlike DarkMystic (BlackBit), which often targets specific organizations, PayForRepair attacks appear more opportunistic
• While Hellcat uses sophisticated evasion techniques, PayForRepair relies more on direct RDP compromise
• Compared to VerdaCrypt, which employs advanced data exfiltration, PayForRepair focuses primarily on encryption
• Unlike LockBit 4.0, which operates on a Ransomware-as-a-Service model, PayForRepair appears to be operated by a single threat actor or small group

Conclusion

PayForRepair ransomware represents a significant threat to Windows users, particularly those with vulnerable RDP configurations. As a member of the Dharma ransomware family, it employs strong encryption techniques that make file recovery without backups extremely difficult.

The primary distribution method for PayForRepair is through brute-force attacks on RDP services, highlighting the importance of implementing strong RDP security measures. Additionally, maintaining a comprehensive backup strategy remains the most effective defense against the impact of ransomware attacks.

Security experts strongly advise against paying the ransom demanded by PayForRepair operators, as there is no guarantee of receiving working decryption tools, and such payments fund further criminal activities. Instead, focus on prevention through security best practices and ensuring reliable backups are maintained.

If you’ve been affected by PayForRepair or other ransomware, take immediate steps to isolate affected systems, remove the malware, and explore recovery options through backups or data recovery tools. For professional assistance with malware removal, consider using specialized security tools designed to detect and eliminate ransomware infections.