Tescrypt

Overview

Ransom:Win32/Tescrypt (universally known as TeslaCrypt) is an infamous, highly destructive file-encrypting ransomware family that emerged in 2015. It initially gained massive notoriety by uniquely targeting PC gamers, specifically encrypting video game save files, Steam configurations, and custom maps, before evolving to target all standard business documents and databases.

Understanding Tescrypt (TeslaCrypt)
For the victim, a Tescrypt infection is an absolute catastrophe. Their wallpaper is replaced with a ransom note, and every personal file (often appended with extensions like `.ecc`, `.ezz`, `.exx`, or `.vvv`) is locked behind strong AES cryptography. The attackers demanded payment in Bitcoin for the decryption key. For security analysts, Tescrypt represents the rapid evolution of the Ransomware-as-a-Service (RaaS) model. Notably, in a rare turn of events, the developers behind TeslaCrypt eventually shut down their operation in 2016 and publicly released the master decryption key, allowing victims to recover their files for free.

Execution and Evasion Strategies
Tescrypt was primarily distributed via massive spam campaigns and Exploit Kits (specifically the Angler EK) hosted on compromised websites. Upon execution, the malware establishes persistence via the Registry Run keys (`T1547.001`). It deletes the Windows Volume Shadow Copies (`vssadmin.exe Delete Shadows /All /Quiet`) to prevent easy recovery (`T1490`). It then iterates through all local drives, mapped network shares, and connected USBs (`T1083`), utilizing AES-256 encryption to scramble the contents of targeted files (`T1486`). Tescrypt famously targeted over 180 specific file extensions, including those associated with Call of Duty, World of Warcraft, and Minecraft, alongside standard Office documents.

Indicators of Compromise & Impact
The impact is a total loss of data availability and severe business disruption. EDR platforms will flag the rapid, high-volume file modification operations (`WriteFile`) across user directories, coupled with the execution of `vssadmin.exe`. The presence of dropped ransom notes (e.g., `HELP_RESTORE_FILES.txt` or `HOWTO_RESTORE_FILES.bmp`) in every encrypted directory is the definitive IoC. Network logs may show Tor-based traffic reaching out to the payment portals.

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

Sigma Rule

title: Suspicious Tescrypt Activity
id: 43cc9ee698412f123e495a1e950e47c5
status: experimental
description: Detects generic indicators of the tescrypt malware family.
logsource:
    category: process_creation
    product: windows
detection:
    selection:
        Image|endswith:
            - '\cmd.exe'
            - '\powershell.exe'
        CommandLine|contains:
            - "*tescrypt*"
    condition: selection
level: medium

Containment & Response Steps

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

1. Instantly sever the endpoint from the network, prioritizing the disconnection of mapped drives to prevent the ransomware from destroying corporate file shares.
2. Do NOT reboot the machine immediately; a reboot may trigger secondary encryption routines or destroy the master key stored temporarily in RAM.
3. Because the master decryption key for Tescrypt was released publicly in 2016, use free, trusted decryption tools (e.g., from ESET or Kaspersky) to recover the files.
4. Perform a full forensic review to identify the initial infection vector (e.g., Angler EK via a compromised ad network) to patch the vulnerability.

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; the infrastructure is defunct, the operators are gone, and a free decryptor exists.
2. Avoid relying solely on file deletion; ensure the registry persistence mechanisms are completely removed so it does not re-execute.

References & External Analysis

• Search "tescrypt" on VirusTotal (External Analysis)

Frequently Asked Questions

Related Families (Category: ransomware)

Explore other malware families in the same category:

• Genericrxcv
• Gendelfan
• Powzip
• Jevafus
• Pandex

Machine-readable

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