Btcware

Overview

Ransomware:Win32/Btcware is a highly destructive ransomware family that emerged around 2017. Its primary objective is to encrypt the victim's files using strong cryptographic algorithms (typically AES-256 combined with RSA-1024) (`T1486`) and extort cryptocurrency (Bitcoin) in exchange for the decryption key. Btcware targets both individual users and corporate networks, causing severe operational disruption and financial loss.

Understanding Btcware (Ransomware)
To an end-user, a Btcware infection is catastrophic. They will suddenly find their documents, photos, and databases inaccessible, appended with extensions like `.btcware`, `.cryptobyte`, `.onyon`, or `.xfile`. A stark Ransom Note (`HELP.txt` or `!#_HOW_TO_DECRYPT_#!.html`) will appear on the desktop. For an organization, it represents a critical incident requiring immediate network isolation.

Execution and Encryption Mechanics
Btcware is frequently deployed manually by attackers who have compromised the network via exposed RDP ports (`T1133`), or delivered via exploit kits. Upon execution, it aggressively deletes Volume Shadow Copies (`vssadmin.exe delete shadows`) (`T1490`) to prevent easy data recovery. It then rapidly traverses local drives and mapped network shares, encrypting files. The malware generates a unique encryption key for the victim, which is then encrypted with the attacker's public RSA key. The ransomware note demands contact via email (often ProtonMail) to negotiate the ransom.

Indicators of Compromise & Impact
The impact is the total loss of data availability. Host-based IoCs are highly visible: the sudden renaming of thousands of files with specific extensions (e.g., `.[email@address.com].btcware`), the presence of ransom notes, and EDR alerts for rapid, high-volume file modification operations. System logs will show the execution of commands designed to inhibit system recovery (`vssadmin`, `bcdedit`). Network IoCs include a brief burst of traffic as the malware reports the infection, though Btcware can encrypt offline.

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

Sigma Rule

title: Suspicious Btcware Activity
id: abb9af58772a459e07e2ca8118ecffb1
status: experimental
description: Detects generic indicators of the btcware malware family.
logsource:
    category: process_creation
    product: windows
detection:
    selection:
        Image|endswith:
            - '\cmd.exe'
            - '\powershell.exe'
        CommandLine|contains:
            - "*btcware*"
    condition: selection
level: medium

Containment & Response Steps

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

1. Isolate the infected machine from the network immediately—pull the ethernet cable or disable the Wi-Fi adapter to stop the encryption from spreading to network shares.
2. Do not immediately reboot the machine; if the encryption process is active, rebooting may finalize the damage or destroy volatile memory keys.
3. Identify the initial infection vector (e.g., exposed RDP, phishing) and secure it to prevent reinfection.
4. Restore operations from known-good, offline backups; paying the ransom is highly discouraged.

What to Avoid

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

1. Do not connect backup drives to the infected machine until it has been completely wiped and reimaged, as Btcware will encrypt the backups.
2. Avoid communicating directly with the attackers without the assistance of professional incident responders or law enforcement.

References & External Analysis

• Search "btcware" on VirusTotal (External Analysis)

Frequently Asked Questions

Related Families (Category: ransomware)

Explore other malware families in the same category:

• Cycbot
• Dodiw
• Xiquitir
• Niwaa8Lfbrj
• Xnhmeb

Machine-readable

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