Teslacrypt

Overview

Ransomware:Win32/Teslacrypt is a historically devastating ransomware family that terrorized the internet between 2015 and 2016. What made TeslaCrypt uniquely infamous was its highly specific targeting: alongside standard documents, it explicitly targeted the save files, profiles, and custom maps of over 40 popular video games (including Call of Duty, World of Warcraft, and Minecraft) to emotionally extort PC gamers. In a stunning and highly unusual turn of events, the developers of TeslaCrypt abruptly shut down operations in May 2016 and published the universal master decryption key for free.

Understanding TeslaCrypt
To a victim, TeslaCrypt was devastating, locking away hundreds of hours of gaming progress alongside vital documents, usually appending extensions like `.ecc`, `.ezz`, `.exx`, or `.xyz` to the encrypted files. For security analysts, TeslaCrypt represented the rapid evolution and commercialization of the ransomware-as-a-service (RaaS) model, utilizing aggressive exploit kits for massive, indiscriminate distribution.

Execution and Encryption Mechanics
TeslaCrypt was predominantly distributed via the notorious Angler Exploit Kit (`T1189`), infecting users simply by them visiting a compromised website (drive-by download). Upon execution (`T1204.002`), it established persistence via the Registry (`T1547.001`) and deleted volume shadow copies (`vssadmin.exe delete shadows`) (`T1490`) to prevent easy recovery. It utilized strong AES encryption (`T1486`), explicitly scanning for over 185 file extensions (`T1083`), uniquely prioritizing gaming-related formats (`.sav`, `.w3x`, `.sc2save`). It then dropped a ransom note (`HELP_RESTORE_FILES.txt`) demanding payment in Bitcoin (usually around $500).

Indicators of Compromise & Impact
The impact was massive data loss and emotional extortion of consumers. The primary IoC was the sudden alteration of file extensions to specific TeslaCrypt variants (`.ecc`, `.vvv`, `.micro`) and the appearance of the ransom notes. Network logs would show the malware reaching out to a Tor-based C2 server to register the infection and upload the unique victim ID.

MITRE ATT&CK Techniques

Observed techniques used by this family, mapped to the MITRE ATT&CK framework:

Generated Detections (Boilerplate)

These YARA and Sigma rules are auto-generated based on the family name and aliases. They must be heavily tuned before deployment in a production environment.

YARA Rule

rule MALWARE_WIN_TESLACRYPT {
    meta:
        description = "Detects Teslacrypt (ransomware)"
        author = "SystemHelpdesk Boilerplate Generator"
        date = "2026-07-06"
    strings:
        $s1 = "teslacrypt" ascii wide nocase
    condition:
        uint16(0) == 0x5a4d and any of them
}

Sigma Rule

title: Suspicious Teslacrypt Activity
id: 8f81fc15a1676fbd1f8b07efdcdbbe7b
status: experimental
description: Detects generic indicators of the teslacrypt malware family.
logsource:
    category: process_creation
    product: windows
detection:
    selection:
        Image|endswith:
            - '\cmd.exe'
            - '\powershell.exe'
        CommandLine|contains:
            - "*teslacrypt*"
    condition: selection
level: medium

Containment & Response Steps

Ordered checklist for responders. Adapt to your environment and engage professional support for active incidents.

1. If encountering a legacy TeslaCrypt infection, DO NOT format the drive. The universal master decryption key is publicly available, and tools exist (e.g., from ESET or McAfee) to recover 100% of the files for free.
2. Isolate the endpoint to prevent any potential lateral movement, although TeslaCrypt primarily focused on local and mapped drive encryption.
3. Run the free TeslaCrypt decryption tool to restore the encrypted files.
4. Use an enterprise antivirus solution to scan for and remove the dormant TeslaCrypt executable and its associated registry persistence mechanisms.

What to Avoid

Common mistakes during response to this family that can destroy evidence, spread the infection, or worsen recovery.

1. Do NOT pay the ransom under any circumstances; the operation is defunct, the infrastructure is offline, and a free decryptor exists.
2. Avoid deleting the encrypted files in a panic; they are fully recoverable using the public master key.

References & External Analysis

• Search "teslacrypt" on VirusTotal (External Analysis)

Frequently Asked Questions

Related Families (Category: ransomware)

Explore other malware families in the same category:

• Sokuxuan
• Chinbo
• Brobaneup
• Redneck
• Rukometa

Machine-readable

Get this profile as JSON: https://jordan123234-malware-families-explorer.static.hf.space/api/teslacrypt.json

Ecosystem & Interactive Environments

This profile is part of the Malware Families Catalog, a public dataset of 2,899 malware families. The catalog is also published across our ecosystem: Hugging Face, Kaggle, Zenodo, Replit, StackBlitz, CodeSandbox, and CodePen.