Cpuminer

Overview

Trojan:Win32/Cpuminer (often a generalized classification for multiple variants) represents a massive shift in cybercrime monetization: **Cryptojacking**. Instead of stealing data or demanding a ransom, Cpuminer silently hijacks the processing power (CPU/GPU) of the infected endpoint or server to mine cryptocurrency (most commonly Monero/XMR) and deposits the generated coins into the attacker's wallet.

Understanding Cpuminer (Cryptojacking)
To an end-user, a Cpuminer infection manifests as severe system sluggishness, loud cooling fans, and drastically reduced battery life on laptops. For an enterprise, a widespread cryptominer outbreak represents a massive theft of computing resources (driving up AWS/Azure cloud compute bills astronomically) and indicates a severe vulnerability that could easily be exploited to deploy ransomware instead.

Execution and Resource Hijacking Mechanics
Cpuminer variants are distributed via every conceivable vector: phishing, exploit kits, exposed RDP servers, and crucially, exploiting unpatched web servers (like WebLogic, Apache Struts, or vulnerable Docker APIs) (`T1190`). The payloads are often modified versions of open-source mining software like XMRig. Upon execution, the miner establishes persistence (via Scheduled Tasks or WMI event subscriptions) (`T1546.003`). It employs evasion tactics like 'Process Hollowing' (`T1055.012`) to hide the mining activity inside legitimate processes (like `svchost.exe` or `notepad.exe`). Advanced variants monitor Task Manager; if the user opens Task Manager to investigate the high CPU usage, the miner temporarily pauses its activity (`T1562.001`), resuming only when Task Manager is closed. The malware then utilizes nearly 100% of available CPU cycles (`T1496`) to calculate hashes, communicating continuously with a mining pool via the Stratum protocol (often over port 3333, 4444, or disguised as HTTPS/8080) (`T1071.001`).

Indicators of Compromise & Impact
The impact is hardware degradation, massive power consumption, and degraded server performance. Host-based IoCs include persistent 90-100% CPU usage by unrecognized or system processes, and EDR alerts for known mining command-line arguments (e.g., `-o stratum+tcp://... -u [wallet_address] -p x`). Network IoCs include continuous, long-lived connections to known mining pool domains (e.g., `minexmr.com`, `supportxmr.com`).

MITRE ATT&CK Techniques

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

Tactical Mitigations

Based on the techniques used by this family, consider the following defensive strategies:

• T1071.001: Implement web filtering and SSL/TLS inspection to detect malicious command and control (C2) traffic hiding in HTTP/HTTPS.

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

Sigma Rule

title: Suspicious Cpuminer Activity
id: ea04b85eaa26b75904fcdcf6eaa5a54e
status: experimental
description: Detects generic indicators of the cpuminer malware family.
logsource:
    category: process_creation
    product: windows
detection:
    selection:
        Image|endswith:
            - '\cmd.exe'
            - '\powershell.exe'
        CommandLine|contains:
            - "*cpuminer*"
    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 endpoint or server; if it is a cloud instance, immediately take a snapshot and then shut down the instance to halt the billing impact.
2. Use EDR or Sysinternals Process Explorer to identify the specific process consuming the CPU and terminate it.
3. Block known mining pool domains and Stratum protocol ports (3333, 4444, etc.) at the perimeter firewall.
4. Investigate the initial vector: cryptominers on servers almost always indicate an unpatched vulnerability or an exposed management interface (like RDP or SSH).

What to Avoid

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

1. Do not dismiss high CPU alerts as just 'bad performance'; investigate them as potential security incidents.
2. Avoid simply killing the process and moving on; most modern miners have watchdogs (secondary scheduled tasks) that will restart the miner immediately.

References & External Analysis

• Search "cpuminer" on VirusTotal (External Analysis)

Frequently Asked Questions

Related Families (Category: ransomware)

Explore other malware families in the same category:

• Randrew
• Jigsawlocker
• Hamaetot
• Quant
• Ciyaamgnrsg

Machine-readable

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