Strike Ransomware Decryptor

Classification: Ransomware, Crypto-Virus, Files-Locker
Family: MedusaLocker
Severity: Critical

Executive Summary

The Strike ransomware family represents a sophisticated and highly adaptive threat within the MedusaLocker ecosystem. It is distinguished by its multi-platform attack capability, targeting not only Windows endpoints but also Linux servers and VMware ESXi hypervisors. The malware employs a formidable RSA+AES hybrid encryption scheme, appending a numerical signature—such as .strike7, .strike10, .strike15, .strike25, and so on—to all compromised files. This offensive is coupled with a ruthless double-extortion strategy, exfiltrating sensitive data to leverage against victims. This document provides an in-depth technical analysis, a complete catalog of Indicators of Compromise (IOCs), a detailed mapping of Tactics, Techniques, and Procedures (TTPs), and a multi-path recovery protocol designed for enterprise-grade incident response across all affected platforms.

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Threat Intelligence & Technical Dissection

Threat Fingerprint

Attribute	Details
Threat Name	Strike (MedusaLocker)
Platform	Windows, Linux, VMware ESXi
Encrypted Files Extension	.strike7, .strike10, .strike15, .strike25, etc.
Ransom Note	READ_NOTE.html
Free Decryptor Available?	No (Publicly)
C2/Contact	[email protected], [email protected], Tor chat
Detection Names	Avast (Win64:MalwareX-gen [Ransom]), Combo Cleaner (Gen:Variant.Tedy.767529), ESET-NOD32 (Win64/Filecoder.MedusaLocker.A Trojan), Kaspersky (HEUR:Trojan-Ransom.Win32.Generic), Microsoft (Ransom:Win64/MedusaLocker.MZT!MTB)

Ransom Note Deconstruction

The READ_NOTE.html file is a masterclass in psychological coercion, meticulously crafted to manipulate the victim’s decision-making process under duress.

• False Benevolence: The initial claim that files are “safe” and “modified” is a calculated lie designed to prevent victims from attempting independent recovery or shutting down the system, thereby preserving the attacker’s control.
• Technical Intimidation: The warning that third-party software will “permanently corrupt” files is a standard tactic to undermine confidence in security solutions and steer victims toward the attacker’s “solution.”
• The Double-Edged Sword: The exfiltration threat is the core of the double-extortion model. It transforms the attack from a simple data availability issue into a critical data confidentiality and compliance breach, significantly increasing the pressure to pay.
• The “Proof of Life” Gambit: The offer to decrypt 2-3 files for free is a low-cost, high-reward strategy for the attackers. It validates their capability, builds a sliver of trust, and makes the prospect of a full recovery seem tangible.

Ransom Note (Full Text)

Your personal ID: -
YOUR COMPANY NETWORK HAS BEEN PENETRATED
Your files are safe! Only modified.(RSA+AES)
ANY ATTEMPT TO RESTORE YOUR FILES WITH THIRD-PARTY SOFTWARE WILL PERMANENTLY CORRUPT IT. DO NOT MODIFY ENCRYPTED FILES. DO NOT RENAME ENCRYPTED FILES.
No software available on internet can help you. We are the only ones able to solve your problem. We gathered highly confidential/personal data. These data are currently stored on a private server. This server will be immediately destroyed after your payment. If you decide to not pay, we will release your data to public or re-seller. So you can expect your data to be publicly available in the near future.. We only seek money and our goal is not to damage your reputation or prevent your business from running. You will can send us 2-3 non-important files and we will decrypt it for free to prove we are able to give your files back.
Contact us for price and get decryption software.
email: [email protected]
[email protected]
* To contact us, create a new free email account on the site: protonmail.com
IF YOU DON'T CONTACT US WITHIN 72 HOURS, PRICE WILL BE HIGHER.
* Tor-chat to always be in touch:

Indicators of Compromise (IOCs) & Attack Lifecycle (TTPs)

• File IOCs:
  • Encrypted Files: Files appended with .strike[number] (e.g., 1.jpg.strike7, document.pdf.strike15, server.conf.strike25).
  • Ransom Note: READ_NOTE.html in affected directories.
• Behavioral IOCs:
  • Desktop Wallpaper: Modified to display ransom instructions.
  • VSS Deletion: Execution of vssadmin.exe Delete Shadows /All /Quiet to eliminate shadow copies.
  • ESXi Specific: VMs may be powered off, and esxcli commands may be used to enumerate and encrypt datastores.
• MITRE ATT&CK Framework Mapping:
  • TA0001 – Initial Access: Phishing (T1566), Exploitation of Public-Facing Application (T1190), Valid Accounts (T1078) via compromised credentials (especially for ESXi).
  • TA0002 – Execution: Command and Scripting Interpreter (T1059), User Execution (T1204).
  • TA0003 – Persistence: Scheduled Task/Job (T1053), Create Account (T1136) for persistence on Linux/ESXi.
  • TA0005 – Defense Evasion: Impair Defenses (T1562) by terminating AV processes, Indicator Removal on Host (T1070) by deleting VSS copies and logs.
  • TA0040 – Impact: Data Encrypted for Impact (T1486), Service Stop (T1489) to stop VM-related services on ESXi, Inhibit System Recovery (T1490) by deleting backups.

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Enterprise Incident Response & Recovery Protocols

Immediate Containment & Eradication

1. Network Segmentation & Isolation:
   • Windows/Linux: Immediately disconnect all affected endpoints from the network. Disable Wi-Fi and unplug Ethernet cables.
   • ESXi: Place the compromised host in maintenance mode. Disconnect it from the network and vCenter Server to prevent the ransomware from propagating to other hosts and datastores.
2. Backup Preservation: Disconnect all network-attached storage (NAS), storage area networks (SANs), and external backup drives. This is your most critical asset; protect it at all costs.
3. Malware Eradication:
   • Windows: Reboot into Safe Mode with Networking. Use Task Manager to terminate suspicious processes and run a full system scan with a reputable AV/EDR solution.
   • Linux: Boot into a rescue environment or use a live CD. Mount the affected filesystems read-only and scan them with a Linux-capable antivirus scanner. Audit cron jobs, init.d scripts, and user startup files for malicious entries.
   • ESXi: Do not attempt to clean the host. The standard procedure is to wipe the host and reinstall ESXi after recovering the VMs from backups.

Recovery Pathways – A Multi-Tiered Strategy

Path A: The Gold Standard – Backup Restoration

As no public decryptor exists, a validated, offline backup is the only guaranteed path to a full and secure recovery.

• Verification: Before restoration, rigorously verify backup integrity on a clean, isolated system. Ensure the backup set is free of any .strike[number] files.
• Procedure: Perform a clean OS reinstallation on all affected hardware (Windows, Linux, ESXi). This eliminates any potential for persistent malware.
• Platform-Specific Restoration:
  • Windows: Restore from a full system image or use File History/Previous Versions.
  • Linux: Restore from validated tape, disk, or cloud backups using tools like rsync, Borg, or Restic.
  • Virtualization (ESXi/Hyper-V): Restore virtual machines from pre-infection snapshots. For enterprise environments, solutions like Veeam provide immutable backup storage and rapid recovery capabilities, ensuring you can recover operations quickly and securely.

Path B: The Advanced Solution – Specialized Decryption Tool

When no viable backups exist, the situation becomes a critical recovery operation. Our Medusa Decryptor is engineered to counter MedusaLocker and its variants, including the multi-platform Strike threat.

• Technical Architecture: The decryptor is not a simple key-guessing tool. It employs a sophisticated, multi-layered approach:
  • AI-Powered Cryptographic Analysis: The tool uses advanced AI to analyze the specific cryptographic implementation of the Strike sample on the affected platform. It hunts for flaws, patterns, or vulnerabilities in key generation or memory handling.
  • Blockchain-Enhanced Intelligence: We leverage a decentralized, blockchain-based network to securely share and aggregate intelligence on new ransomware variants globally. This allows our system to identify and exploit weaknesses with unprecedented speed.
  • Distributed Server Network: Our powerful online server farm performs the intensive computational work required to test potential keys and exploit any discovered weaknesses, making it possible to tackle the complex RSA+AES encryption used by Strike.

While a public free decryptor is unavailable, our team is actively analyzing the variant. The Medusa Decryptor is continuously updated and represents the most promising path to recovery without paying the ransom.

Path C: The Last Resort – Forensic Data Recovery

If backups and a decryptor are not options, the probability of full recovery is low. However, forensic data recovery software can be employed in a final attempt to salvage unencrypted file fragments.

• Recommended Tools: EaseUS Data Recovery Wizard, Stellar Data Recovery, R-Studio, TestDisk & PhotoRec.
• Procedure: Install the recovery application on a sterile, separate machine. Connect the affected drive as a read-only slave. Scan for lost files and save any recoverable data to a different, clean destination. Do not write anything to the affected drive.
• Platform-Specifics:
  • Linux: Use TestDisk and PhotoRec to perform file carving on unmounted, affected partitions. This is a low-level process with a low probability of recovering structured, intact files.
  • ESXi: Recovery is exceptionally difficult. The only viable option is a professional data recovery service specializing in VMFS datastores. This is a costly, time-consuming process with no guarantee of success.

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Post-Incident Actions & Strategic Hardening

1. Validation & Integrity Check: Thoroughly verify the integrity and functionality of all restored files before reconnecting systems to the network.
2. Credential Reset & Access Review: Mandate a full password reset for all user and service accounts, especially administrators, from a trusted, clean endpoint. This includes ESXi root accounts, vCenter, and all guest OS credentials. Review and audit all access controls.
3. System Hardening & Patch Management: Apply all pending security patches to the OS and all third-party applications. Review and tighten firewall rules, especially for RDP, SSH, and other remote access protocols.
4. Security Policy Review & Training: Conduct a thorough post-mortem to analyze the attack vector. Update security policies, incident response plans, and conduct mandatory employee security awareness training focusing on phishing, social engineering, and safe browsing practices.
5. Backup Strategy Overhaul: Implement and enforce a 3-2-1 backup strategy (3 copies of data, on 2 different media, with 1 copy off-site and offline). Conduct regular, tested restoration drills for all critical platforms, including virtual machines.
6. Platform-Specific Hardening:
   • Linux: Secure SSH by disabling root login and using key-based authentication. Employ a host-based firewall like ufw or iptables.
   • ESXi: Lock down the ESXi Shell and SSH by default. Use the VMware vSphere Hardening Guide as a mandatory checklist. Separate management networks from production VM networks using VLANs.

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Conclusion

The Strike ransomware family is a formidable adversary due to its strong encryption, cross-platform capabilities, and ruthless double-extortion tactics. A structured, methodical incident response is paramount. Leveraging our specialized Medusa Decryptor offers the highest probability of a successful, non-payment recovery. However, the ultimate goal is resilience. A robust, tested backup strategy combined with a defense-in-depth security posture—encompassing proactive system hardening, network segmentation, and continuous user education—is the only true long-term defense against such existential threats.

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