Bruteforce
Table of Contents
Overview
BruteForce (classified across antivirus engines as HackTool:Win32/BruteForce and Tool:Win32/BruteForce) is a multi-protocol authentication credential-cracking tool used by threat actors and penetration testers to gain unauthorized initial access and execute internal lateral movement. Designed for high-concurrency dictionary and rainbow-table attacks, BruteForce targets Windows administrative services, including Remote Desktop Protocol (RDP - port 3389), Server Message Block (SMB - port 445), MSSQL (port 1433), and SSH (port 22). Threat actors deploy it on internet-facing scanning servers or compromised internal workstations to systematically iterate through wordlists of usernames and passwords, generating alerts across security event logs (Event IDs 4625).
Known aliases
Threat reports may refer to this family under multiple names:
MITRE ATT&CK Techniques
Observed techniques used by this family, mapped to our technical analysis hubs and the official MITRE ATT&CK framework:
| Technique | Name | Tactic | Official Spec |
|---|---|---|---|
T1110.001 | Brute Force: Password Guessing | Credential Access | ATT&CK ↗ |
T1110.002 | Brute Force: Password Cracking (Offline) | Credential Access | ATT&CK ↗ |
T1110.003 | Brute Force: Password Spraying | Credential Access | ATT&CK ↗ |
T1059.003 | Command and Scripting Interpreter: Windows Command Shell | Execution | ATT&CK ↗ |
T1078 | Valid Accounts (The goal of the attack) | Initial Access | ATT&CK ↗ |
Tactical Mitigations
Based on the techniques used by this family, consider the following defensive strategies:
- T1059.003: Restrict execution of Windows Command Shell (cmd.exe) and block unauthorized batch scripts.
MITRE D3FEND™ Defensive Countermeasures
Defensive techniques mapped to counter the offensive tradecraft observed in this family (via the MITRE D3FEND matrix):
| D3FEND ID | Countermeasure Name | Tactic | Countered ATT&CK | Defensive Guidance |
|---|---|---|---|---|
D3-PBA | Process Spawn Analysis | Detect | T1059.003 | Inspect command-line arguments and anomalous parent-child relationships spawning from cmd.exe. |
D3-MFA | Multi-factor Authentication | Harden | T1078 | Enforce mandatory phishing-resistant FIDO2 multi-factor authentication across all external access portals. |
D3-AL | Account Lockout Policy | Harden | T1110.001 | Enforce progressive delay and lockout thresholds on failed authentication attempts to thwart brute-force password guessing. |
Tiered Detection Rules (Cisco CAIRN Model)
Modern threat detection requires multi-layered rule engineering. We classify detections into three operational tiers based on signal fidelity:
Tier 1 Primitive Artifact Rule (Fast Triage)
Matches raw strings and file markers. Vulnerable to binary repacking and simple obfuscation.
rule MALWARE_WIN_BRUTEFORCE_T1_ARTIFACT {
meta:
description = "Tier 1 Primitive Artifact: Raw string matches for Bruteforce"
tier = "T1 - Primitive Artifact"
confidence = "Low-Medium (Fast Triage)"
author = "SystemHelpdesk Threat Research Desk"
date = "2026-10-14"
strings:
$s1 = "bruteforce" ascii wide nocase
$s2 = "hacktool:win32/bruteforce" ascii wide nocase
$s3 = "tool:win32/bruteforce" ascii wide nocase
$s4 = "win32/bruteforce" ascii wide nocase
$s5 = "rdp bruteforce tool" ascii wide nocase
$s6 = "bruteforce password cracker" ascii wide nocase
condition:
uint16(0) == 0x5a4d and any of them
}Tier 2 Behavioral Context Rule (Process Chains & Sigma)
Tracks parent-child process anomalies and suspicious scripting telemetry. Resilient against file renames.
title: SystemHelpDesk Detection - Bruteforce (Hacktool) Execution & Triage
id: fa4130ae-94d5-5deb-bce3-de199b0eb07e
status: production
description: Detects execution, defense evasion, and persistence behaviors associated
with the Bruteforce malware family. Detects suspicious execution from temporary
user directories with hidden window flags and background transfer utilities.
references:
- https://malware-families-catalog.systemhelpdesk.com/families/bruteforce
- https://malware-families-catalog.systemhelpdesk.com/defensive/ransomware-protection
- https://malware-families-catalog.systemhelpdesk.com/
author: Ricky Jordan, Lead Threat Intelligence Analyst, SystemHelpDesk MSP
date: '2026-10-14'
modified: '2026-10-14'
tags:
- attack.hacktool
- author.ricky-jordan
- source.systemhelpdesk-mfc
- attack.t1110_001
- attack.t1110_003
- attack.t1021_001
- attack.t1021_002
- attack.t1046
logsource:
category: process_creation
product: windows
detection:
selection_process:
Image|endswith:
- \cmd.exe
- \powershell.exe
- \cscript.exe
- \wscript.exe
CommandLine|contains:
- AppData\Local\Temp
- -WindowStyle Hidden
- /e:jscript
- bitsadmin /transfer
condition: selection_process
falsepositives:
- Legitimate enterprise administrative scripts during approved change windows
- Authorized IT software deployment utilities and backup management agents
level: mediumTier 3 Attribution Fingerprint Rule (High Fidelity)
Deep signature matching distinctive operational fingerprints and payload characteristics.
rule MALWARE_WIN_BRUTEFORCE_T3_ATTRIBUTION {
meta:
description = "Tier 3 Attribution Fingerprint: Heuristic detection for Bruteforce tradecraft"
tier = "T3 - Attribution Fingerprint"
confidence = "High (Confirmed Family Signature)"
author = "SystemHelpdesk Threat Research Desk"
date = "2026-10-14"
strings:
// Core family identifier & heuristic payload signatures
$attrib_str = "bruteforce" ascii wide nocase
$pe_magic = "MZ" ascii
$net_marker = "http" ascii nocase
condition:
uint16(0) == 0x5a4d and ($attrib_str and $net_marker) and filesize < 15MB
}Containment & Response Steps
Ordered checklist for responders. Adapt to your environment and engage professional support for active incidents.
- If the alert indicates an active network brute-force attack, immediately isolate the targeted system or block the source IP address at the firewall.
- Analyze Windows Security Event Logs (Event ID 4625) to determine which accounts are being targeted; if a successful login (4624) is found from the attacking IP, consider that account compromised.
- If an offline cracking tool (like Hashcat) is found, isolate the machine to determine *how* the attacker obtained the password hashes in the first place (e.g., did they dump LSASS?).
- Enforce a mandatory enterprise-wide password reset if Domain Admin hashes were potentially cracked.
What to Avoid
Common mistakes during response to this family that can destroy evidence, spread the infection, or worsen recovery.
- Do not ignore the alert simply by deleting the tool; the presence of the tool indicates an attacker is already inside the network attempting to escalate privileges.
- Avoid relying solely on account lockouts to stop brute-forcing; modern attackers use 'Password Spraying' (trying one common password across all users) to avoid triggering lockout policies.
References & External Analysis
- Microsoft Defender Threat Encyclopedia - HackTool:Win32/BruteForce
- Trend Micro Security Research - HackTool.Win32.Bruteforce
- MITRE ATT&CK - Brute Force: Password Guessing (T1110.001)
- Search "bruteforce" on VirusTotal (External Analysis)
- Search "bruteforce" on Any.Run (Sandbox Sandbox)
- Search "bruteforce" on MalwareBazaar (Malware Samples)
Frequently Asked Questions
What is HackTool:Win32/BruteForce?
BruteForce is an automated password cracking tool used by attackers to guess credentials on services like RDP, SMB, and SQL.
Which protocols are targeted by BruteForce tools?
Remote Desktop Protocol (RDP), Server Message Block (SMB), SSH, FTP, and Microsoft SQL Server (MSSQL).
How does BruteForce facilitate lateral movement?
Once inside a corporate network, it scans internal subnets to guess local administrator credentials across neighboring hosts.
What Windows event logs indicate a brute-force attack?
High volumes of Event ID 4625 (failed logon attempts) followed by Event ID 4624 (successful logon) from the same IP.
How can organizations protect against BruteForce tools?
Enforce multi-factor authentication (MFA), account lockout thresholds, strong password policies, and disable public-facing RDP.
How do I remove Bruteforce from Windows?
Manual removal of Bruteforce is highly discouraged as it may leave persistence mechanisms intact. We recommend disconnecting the device from the internet and utilizing a professional incident response service or enterprise-grade EDR software to conduct a full forensic sweep.
Is Bruteforce a virus or a Hacktool?
Bruteforce is classified as a Hacktool. Unlike traditional viruses that infect files, modern malware like Bruteforce typically operates as a standalone payload designed to compromise systems, steal data, or deploy secondary stage implants.
What are the main symptoms of a Bruteforce infection?
Symptoms of Bruteforce can include unexpected system slowness, unauthorized outbound network traffic to unknown IP addresses, disabled security software, and suspicious background processes running from AppData or Temp directories.
Protect Your Network Against Hacktools
Want to prevent Bruteforce and similar threats from compromising your organization? Read our comprehensive defensive guide: HackTool & Riskware Protection.
📣 Threat Intel Correction or Update?
Notice an outdated IOC, unlisted alias, or disputed attribution? Threat researchers are invited to propose an update on GitHub or contact the SystemHelpDesk research desk. All community revisions are credited in our public CHANGELOG.
Machine-readable
Get this profile as JSON: https://malware-families-catalog.systemhelpdesk.com/api/bruteforce.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.