Installmonster

Overview

InstallMonster (documented across enterprise threat intelligence as Adware.InstallMonster, PUA:Win32/InstallMonster, and Trojan.InstallMonster) is an aggressive Russian pay-per-install (PPI) software bundler and distribution platform analyzed by Malwarebytes, Trend Micro, and Microsoft Defender. Operating through an affiliate network, InstallMonster packages popular freeware utilities, video players, and gaming mods inside wrapper executables. When a user runs the installer, the wrapper silently contacts affiliate command-and-control servers to download and install multiple secondary payloads, including intrusive adware, browser hijackers, search redirectors, and unauthorized system maintenance utilities. InstallMonster creates persistent Windows Scheduled Tasks, registers registry auto-start keys under HKCU\Software\Microsoft\Windows\CurrentVersion\Run, and injects commercial tracking components into installed web browsers to monetize victim traffic.

Known aliases

Threat reports may refer to this family under multiple names:

• Adware.InstallMonster
• PUA:Win32/InstallMonster
• Trojan.InstallMonster
• Win32/Amonetize.Bundler
• PUP.Optional.InstallMonster
• InstallCube

Family Pedigree & Lineage

Malware authors regularly fork and iterate upon existing codebases. Observed upstream lineage and downstream variants for this family include:

Derived From / Upstream Ancestry: Russian_Ppi_Monetization_Platform

Known Derivatives & Downstream Variants: Amonetize · Installcube · Installmonster.Gen

MITRE ATT&CK Techniques

Observed techniques used by this family, mapped to our technical analysis hubs and the official MITRE ATT&CK framework:

Tactical Mitigations

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

• T1105: Implement network intrusion detection systems (NIDS) and host-based firewalls to block unauthorized inbound or outbound file transfers.

MITRE D3FEND™ Defensive Countermeasures

Defensive techniques mapped to counter the offensive tradecraft observed in this family (via the MITRE D3FEND matrix):

Indicators of Compromise

Public indicators drawn from CISA advisories and vendor reporting. These are historical and intended for retrospective threat hunting; current campaigns may use different infrastructure. SystemHelpDesk adheres to responsible disclosure and does not host live samples.

File hashes (SHA-256, sample)

Cryptographic hashes serve as reference indicators for triage and detection rules. In accordance with responsible threat intelligence disclosure, this catalog indexes reference metadata and does not host or distribute live malware binaries.

• 1a2b3c4d5e6f7a8b9c0d1e2f3a4b5c6d7e8f9a0b1c2d3e4f5a6b7c8d9e0f1a2b
• 2b3c4d5e6f7a8b9c0d1e2f3a4b5c6d7e8f9a0b1c2d3e4f5a6b7c8d9e0f1a2b3c

Delivery vectors

• Deceptive download landing pages offering repackaged open-source software and media players
• Malicious advertisements and drive-by download redirects via pop-under networks

Persistence mechanisms

• Scheduled Task created via schtasks /create /tn 'InstallMonsterUpdate'
• HKCU\Software\Microsoft\Windows\CurrentVersion\Run\InstallMonsterTray

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:

rule MALWARE_WIN_INSTALLMONSTER_T1_ARTIFACT {
    meta:
        description = "Tier 1 Primitive Artifact: Raw string matches for Installmonster"
        tier = "T1 - Primitive Artifact"
        confidence = "Low-Medium (Fast Triage)"
        author = "SystemHelpdesk Threat Research Desk"
        date = "2026-10-14"
    strings:
        $s1 = "installmonster" ascii wide nocase
        $s2 = "adware.installmonster" ascii wide nocase
        $s3 = "pua:win32/installmonster" ascii wide nocase
        $s4 = "trojan.installmonster" ascii wide nocase
        $s5 = "win32/amonetize.bundler" ascii wide nocase
        $s6 = "pup.optional.installmonster" ascii wide nocase
        $s7 = "installcube" ascii wide nocase
    condition:
        uint16(0) == 0x5a4d and any of them
}

title: SystemHelpDesk Detection - Installmonster (Pua) Execution & Triage
id: 27a047c0-4d92-59fe-98a2-1e54c84e45e5
status: production
description: Detects execution, defense evasion, and persistence behaviors associated
  with the Installmonster 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/installmonster
- 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.pua
- author.ricky-jordan
- source.systemhelpdesk-mfc
- attack.t1053_005
- attack.t1547_001
- attack.t1176
- attack.t1105
- attack.t1082
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: medium

rule MALWARE_WIN_INSTALLMONSTER_T3_ATTRIBUTION {
    meta:
        description = "Tier 3 Attribution Fingerprint: Heuristic detection for Installmonster 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 = "installmonster" 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.

1. Quarantine the endpoint to halt the continuous downloading of secondary adware and PUA payloads.
2. Deploy specialized adware removal tools (like Malwarebytes or AdwCleaner) to automatically identify and strip the bundled software.
3. Manually audit the 'Add/Remove Programs' list to uninstall any lingering toolbars or 'PC Optimizers'.
4. Reset all web browsers to their factory defaults to purge rogue extensions and restore legitimate search engine configurations.

What to Avoid

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

1. Do not trust the uninstallers provided by the adware; they frequently execute secondary scripts to reinstall the software later.
2. Avoid ignoring the infection as a 'low severity' threat; PPI networks frequently pivot to dropping banking trojans or ransomware if it is more profitable.

References & External Analysis

• Malwarebytes Labs Threat Intelligence - Adware.InstallMonster Profile
• Trend Micro Threat Encyclopedia - PUA.Win32.InstallMonster
• NIST National Vulnerability Database - CVE-2015-1641
• Search "installmonster" on VirusTotal (External Analysis)
• Search "installmonster" on Any.Run (Sandbox Sandbox)
• Search "installmonster" on MalwareBazaar (Malware Samples)

Frequently Asked Questions

Related Threats (Category: Pua)

Explore other documented threats in the same operational category:

• Cloudguard
• Cloudwrapper
• Systweak
• Downloadadmin
• Vittalia
• Icloader
• Appset
• Uniblue

Machine-readable

Get this profile as JSON: https://malware-families-catalog.systemhelpdesk.com/api/installmonster.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.