Ransomware Data Recovery Belfast

Swansea Data Recovery: The UK’s No.1 Ransomware Data Recovery Specialists

For 25 years, Swansea Data Recovery has been the UK’s leading specialist in combating data encryption by ransomware. We provide professional forensic decryption and recovery services for all infected systems, including laptops, desktops, external drives, and complex RAID servers. Our state-of-the-art digital forensics laboratory is equipped with advanced computational resources and proprietary tools to tackle the most sophisticated ransomware strains, from widespread threats like WannaCry to advanced persistent threats like LockBit and REvil.

Top 25 Ransomware Decryption & Data Recovery Techniques

Ransomware recovery is a forensic battle that requires a multi-pronged approach. Here is a detailed breakdown of our advanced technical methodologies.

1. Cryptographic Flaw Exploitation (Weak RNG Analysis)

• Summary: Many ransomware strains, especially older or poorly coded variants, use weak or predictable Random Number Generators (RNG) to create encryption keys. This creates a fundamental flaw in their cryptographic implementation.

• Technical Recovery: We perform a deep forensic analysis of the ransomware binary to identify the key generation algorithm. Using a disassembler like IDA Pro, we reverse-engineer the code to find how it seeds its RNG (e.g., using system time, a static value, or a low-entropy system call). We then use this knowledge to brute-force the key space, which can be reduced from an impossible 2^256 to a feasible 2^20 or 2^30 possibilities. Our multi-GPU cracking rigs, running tools like Hashcat or custom C++ code, can test millions of key permutations per second to find the correct decryption key.

2. Brute-Force on Extracted Key Material

• Summary: The ransomware encrypts files with a randomly generated session key, which is then itself encrypted by a master public key (asymmetric encryption). If we can extract the encrypted session key from the infected files, we can target it directly.

• Technical Recovery: We write custom parsers to isolate the RSA-encrypted AES key, which is often appended to or embedded within the encrypted file structure. This encrypted blob is then subjected to a brute-force attack. For strains using weak RSA key lengths (e.g., 512-bit or 768-bit), we can factor the public key using the General Number Field Sieve (GNFS) algorithm on a high-performance computing cluster, effectively deriving the private key and allowing us to decrypt all session keys.

3. Memory Dump Analysis for Residual Keys

• Summary: Volatile RAM (Random Access Memory) on an infected system may still contain the symmetric encryption keys used by the ransomware, which are held in plaintext during the encryption process.

• Technical Recovery: We create a forensic memory image of the infected system using tools like FTK Imager or Belkasoft Live RAM Capturer, preferably while the system is still running or in a hibernated state. We then analyse the memory dump with Volatility or Rekall, using specialized plugins to scan for cryptographic key patterns, ASCII/Unicode strings matching known ransomware key formats, and pointers to memory locations where the ransomware process stored its cryptographic material.

4. Shadow Volume Copy (VSS) Reconstruction

• Summary: Many ransomware strains attempt to delete or encrypt the Volume Shadow Copy Service (VSS) snapshots to prevent easy recovery. However, the data structures on disk are often only marked as deleted, not fully erased.

• Technical Recovery: We use forensic tools like vssadmin and diskpart in conjunction with hex editors to manually scan the System Volume Information folder on the NTFS file system. We look for the GUID-named folders and parse the Shadow Copy {ID} files. Using tools like ShadowExplorer or our own software, we attempt to reconstruct the VSS store by repairing the damaged bitmap and catalog files, granting access to pre-infection file versions.

5. Ransomware Strain Identification & Public Decryptor Deployment

• Summary: Quickly identifying the specific ransomware family is critical, as security researchers often release free decryption tools for strains where a flaw has been discovered.

• Technical Recovery: We analyse the encrypted file extension (e.g., .lockbit, .crypt), the ransom note (_readme.txt, RECOVER-FILES.txt), and the binary’s cryptographic signature. We use automated identification services like ID Ransomware and cross-reference with our internal database. For confirmed strains with public decryptors (e.g., Shade, TeslaCrypt, older versions of STOP/Djvu), we deploy the tool in a sandboxed environment to verify its efficacy before running it on the client’s data image.

6. Configuration File Extraction

• Summary: Many ransomware families use an external configuration file that is downloaded during infection. This file contains critical data such as the attacker’s ID, the ransom amount, and, in some cases, the public key or other cryptographic seeds.

• Technical Recovery: We perform a full forensic disk image and then conduct a deep scan for files created or modified around the time of infection. Using file signature analysis and entropy checks, we identify non-standard files. We then reverse-engineer the ransomware binary to understand the format of its config file (often encrypted or encoded with Base64/XOR). Extracting this data can provide the unique victim identifier, which is sometimes used to generate the decryption key, allowing us to replicate the key generation process.

7. Partially Encrypted File Carving

• Summary: Some ransomware strains are designed to encrypt only the first few megabytes of a file to speed up the process, leaving the remainder of the file intact. This is common with large database files and videos.

• Technical Recovery: We use forensic data carving tools like PhotoRec or R-Studio to perform a raw scan of the disk image. We instruct the software to ignore file system structures and search for file headers and footers (e.g., JPEG SOI, MP4 ftyp). For files with a known structure, we write custom parsers that discard the encrypted header block and reassemble the file using the intact data from the later sectors, effectively salvaging a functional, albeit truncated, version of the original file.

8. Temporary File & Cache Recovery

• Summary: Applications often create temporary copies or caches of files during normal operation. These temporary files may have been overlooked by the ransomware and remain unencrypted.

• Technical Recovery: We conduct a thorough forensic examination of standard and application-specific temp directories (e.g., C:\Users[Username]\AppData\Local\Temp, ~/.cache/). We also analyse the $MFT (Master File Table) to find records of files that have been deleted but whose data may still be resident in the MFT record itself or in unallocated clusters. We recover these temporary and cached files to restore previous versions of the encrypted originals.

9. Negotiation with Attackers (As a Last Resort)

• Summary: When all technical decryption methods fail, and the data is of critical value, engaging with the threat actor may be the only option to obtain the decryption key.

• Technical Recovery: We act as a professional intermediary, using isolated, anonymous communication channels (e.g., Tor-based chat systems provided by the attackers). Our role is to verify that the attacker possesses a valid decryption key (by sending them a small, non-critical encrypted file for decryption), to negotiate the ransom down from the initial demand, and to manage the cryptocurrency payment process to secure the master decryption key or tool, minimizing further risk to the client.

10. Flawed Encryption Algorithm Implementation

• Summary: The ransomware author may have implemented a strong encryption algorithm (like AES) incorrectly, introducing vulnerabilities. Common errors include using a static Initialization Vector (IV) or reusing a key stream.

• Technical Recovery: We analyse the encrypted output of two different files. If the first blocks of both files are identical, it indicates a static IV was used. This weakness can allow us to perform a Known Plaintext Attack (KPA). If we have even one original, unencrypted file from the system, we can XOR it with its encrypted counterpart to derive the key stream, which can then be applied to other encrypted files.

11. Master Decryption Key Leakage

• Summary: In some cases, due to programming errors, the ransomware’s master decryption key is accidentally embedded within the binary itself or leaked in network traffic during the infection.

• Technical Recovery: We perform static analysis on the ransomware executable, searching for large, high-entropy blocks of data that could be an embedded key. We also analyse packet capture (pcap) logs from the network, if available, looking for data exfiltrated around the time of encryption that might contain the key. Strings analysis with tools like FLOSS (FireEye Labs Obfuscated String Solver) can often reveal keys that were obfuscated but not properly hidden.

12. Database Log Replay (For SQL Servers)

• Summary: Database management systems like Microsoft SQL Server or MySQL maintain transaction logs that record every change made to the data. If these logs are intact, the database can be restored to a point in time just before the encryption occurred.

• Technical Recovery: We take the encrypted database (MDF) files and the corresponding transaction log (LDF) files. Using the database engine’s native recovery tools, we restore a backup of the database to a point before the infection and then “replay” the transaction logs up to the second before the ransomware began its work. This requires a clean backup and an unbroken log chain, effectively rolling the database back to its pre-attack state.

13. Email Attachment & Cloud Sync Recovery

• Summary: Files that were recently emailed as attachments or synced to a cloud service (OneDrive, Dropbox, Google Drive) may exist in an unencrypted state on the mail server or in the cloud’s version history.

• Technical Recovery: We work with IT administrators to access the email server’s archives to retrieve sent items containing the files. For cloud-synced folders, we access the service’s web interface and navigate to the version history or trash/recycle bin to restore files to a version from before the encryption event. This is often the fastest and most effective recovery method for recent data.

14. Firmware-Level Ransomware Mitigation

• Summary: Some sophisticated ransomware (e.g., RobbinHood) attempts to encrypt drives at a low level, including the Master Boot Record (MBR) or GUID Partition Table (GPT), to prevent the system from booting.

• Technical Recovery: We remove the drive from the infected machine and connect it to our forensic workstation via a hardware write-blocker. We then use tools like testdisk or gdisk to manually repair the damaged MBR boot code or reconstruct the GPT using its secondary (backup) copy, which is usually stored at the very end of the disk and is often untouched by the malware.

15. Entropy Analysis to Identify Encryption

• Summary: Encrypted data has high, uniform entropy (randomness), whereas normal file types have predictable entropy patterns. This analysis helps us map the scope of the infection.

• Technical Recovery: We use forensic tools like Binwalk or custom Python scripts using the scipy.stats.entropy module to calculate the Shannon entropy of every sector on the drive. By plotting this data, we can visually identify which files and sectors have been encrypted. This helps us isolate encrypted volumes and, crucially, identify unencrypted areas that may contain recoverable data or system files crucial for restoration.

16. Ransomware Bug Exploitation (Logic Bombs)

• Summary: Some ransomware contains “logic bombs” or time-based triggers that can be exploited. For example, if the ransomware checks the system date and refuses to run after a certain date, we can roll back the system clock to create a false environment.

• Technical Recovery: We analyse the ransomware in a sandboxed environment, monitoring its API calls for functions like GetSystemTime. By understanding its time-based logic, we can manipulate the system environment of a virtual machine to trick the ransomware into revealing its decryption routine or simply not executing its payload, allowing us to safely extract keys from memory.

17. File System Journal ($UsnJrnl) Analysis

• Summary: The NTFS USN Journal (Update Sequence Number Journal) logs all changes made to files on the volume, including the ransomware’s creation of encrypted files and deletion of originals.

• Technical Recovery: We parse the $Extend\$UsnJrnl file using forensic tools like analyzeMFT. The journal provides a timeline of the attack, showing the original file names and paths before they were overwritten with encrypted versions. This metadata is invaluable for reconstructing the directory structure and confirming what data was lost, even if the files themselves are encrypted.

18. Hybrid Encryption Attack (Targeting the Asymmetric Layer)

• Summary: Ransomware typically uses a hybrid approach: a fast symmetric key (AES) encrypts the files, and a slow asymmetric key (RSA) encrypts the AES key. We focus attacks on the weaker part of this chain.

• Technical Recovery: If the ransomware uses a weak RSA implementation (e.g., 512-bit keys), as was the case with early versions of Petya, we can factor the public key. We use the Number Field Sieve (NFS) implementation in tools like CADO-NFS on a high-core-count server to factor the modulus (N) into its prime components (p and q), allowing us to calculate the private key (d) and decrypt the AES session keys for all files.

19. Bootkit & MBR Ransomware Removal

• Summary: Ransomware like Petya or Satana encrypts the Master File Table (MFT) and overwrites the MBR, making the entire drive inaccessible upon boot.

• Technical Recovery: We create a sector-by-sector image of the drive. We then manually locate the backup MFT (typically located near the middle of the volume) and use it to rebuild the primary MFT. We then repair or replace the malicious MBR code with a standard one. This process restores access to the file system, revealing the encrypted files, which we then attempt to decrypt using other methods.

20. Side-Channel Attack on Encryption Process

• Summary: By analysing the system’s behaviour during encryption (e.g., power consumption, electromagnetic emissions, or cache timings), it is sometimes possible to extract information about the encryption key.

• Technical Recovery: This is a highly advanced, academic-level attack. In a controlled lab environment, we would run the ransomware sample in a debugger on a specially instrumented system while monitoring power traces with an oscilloscope. By performing Differential Power Analysis (DPA), we can correlate power fluctuations with the cryptographic operations to statistically derive bits of the key. This is typically only attempted for high-value, targeted attacks with no other recourse.

21. Decoy File Entrapment

• Summary: For persistent or targeted attacks, we can strategically place decoy files with known content and unique names on a network share or system. When these files are encrypted, they provide a perfect known-plaintext pair for cryptanalysis.

• Technical Recovery: We pre-seed systems with files containing high-entropy, known data (e.g., a JPEG of a specific size with a unique checksum). When these files are encrypted, we have a direct plaintext-ciphertext pair. This allows us to immediately launch a Known Plaintext Attack (KPA) to derive the session key or identify patterns in the ransomware’s encryption routine, significantly speeding up the development of a decrypter.

22. Ransomware-as-a-Service (RaaS) Takedown Collaboration

• Summary: Many ransomware strains are operated as a service, with the developers selling or leasing the malware to affiliates. Taking down the RaaS infrastructure can sometimes lead to the release of master decryption keys.

• Technical Recovery: We collaborate with international law enforcement (e.g., NCA, FBI, Europol) and cybersecurity firms. By analysing the ransomware’s command-and-control (C2) server communication, we can help identify and attribute the infrastructure. When a takedown occurs, as with the REvil and Hive networks, the seized servers often contain master decryption keys that are subsequently released to the public, which we then use to decrypt victim files.

23. Process Hollowing & Code Injection Analysis

• Summary: Ransomware often injects its malicious code into a legitimate system process (e.g., svchost.exe, explorer.exe) to evade detection. The encryption keys may reside in the memory space of that process.

• Technical Recovery: We use a kernel-level debugger (WinDbg) to attach to the suspicious process without crashing it. We then dump the process’s memory and scan it for executable code sections that are not signed by Microsoft (a sign of injection). Within these injected code caves, we often find the ransomware’s core functions and, critically, the encryption keys that were in use.

24. Custom Decryptor Development

• Summary: For new or obscure ransomware strains without a public decryptor, we develop our own proprietary decryption tools.

• Technical Recovery: This involves full reverse-engineering of the ransomware binary. We use disassemblers (IDA Pro) and debuggers (x64dbg) to step through the encryption routine, mapping out the exact algorithm, key scheduling, and file transformation process. Once we understand the mechanism, we write a C++ or Python script that performs the inverse operation, effectively decrypting the files. This tool is then added to our internal arsenal for future cases.

25. Forensic Imaging & Isolated Analysis

• Summary: The foundational step of all recovery work: creating a forensically sound, bit-for-bit copy of the affected media in a way that prevents any alteration of the original evidence.

• Technical Recovery: We connect the client’s storage device to our Tableau TX1 or Forensic Duplicator hardware write-blocker. Using software like Guymager or FTK Imager, we create a raw (dd) image file and a logical evidence file (E01) complete with MD5/SHA-256 hash verification. All subsequent decryption and analysis is performed on this image, ensuring the original data is preserved and the ransomware is completely isolated from any network, preventing further spread or destruction.

Why Choose Swansea Data Recovery for Ransomware?

• 25 Years of Digital Forensics Expertise: We have been fighting malware since its inception.

• Advanced Computational Resources: Multi-GPU cracking rigs and high-core-count servers for cryptographic attacks.

• Proprietary Tool Development: We create custom decryptors for novel ransomware strains.

• Forensic Rigor: All work is conducted using legally defensible, forensically sound methodologies.

• Collaborative Intelligence: We work with global law enforcement and the cybersecurity community.

• Free Diagnostics: We provide a full assessment of your encrypted system and a clear recovery plan.

Contact Swansea Data Recovery today for a free, confidential forensic evaluation. Do not pay the ransom until you have spoken to the UK’s leading ransomware recovery specialists.