Addrop

Overview

Addrop (cataloged across security vendors as Adware:Win32/Addrop, Adware.Addrop, and PUA:Win32/Addrop) is a persistent adware dropper and Potentially Unwanted Application (PUA) family active since 2014. Unlike simple downloaders that retrieve assets over the internet, Addrop packages multiple adware modules, browser hijackers, and tracking extensions compressed directly within its own executable stub. Distributed primarily through deceptive freeware installers, torrented software cracks, and fake media codec downloaders, Addrop executes silently in the background while displaying simulated setup progress dialogs. Once active, it extracts its payload of advertising frameworks into %ProgramFiles% and %AppData% directories. It modifies the Windows Registry to establish persistent autostart run keys, drops rogue extensions across Google Chrome, Mozilla Firefox, and Microsoft Edge to inject sponsored advertisements into visited websites, and alters DNS or HOSTS settings to redirect user search traffic to affiliate monetization networks.

Known aliases

Threat reports may refer to this family under multiple names:

• Adware:Win32/Addrop
• Adware.Addrop
• PUA:Win32/Addrop
• Trojan.Win32.Addrop

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: Deceptive Adware Bundlers

Known Derivatives & Downstream Variants: Addrop.A · Addrop.B

MITRE ATT&CK Techniques

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

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.

• 7a8b9c0d1e2f3a4b5c6d7e8f9a0b1c2d3e4f5a6b7c8d9e0f1a2b3c4d5e6f7a8b
• 8b9c0d1e2f3a4b5c6d7e8f9a0b1c2d3e4f5a6b7c8d9e0f1a2b3c4d5e6f7a8b9c

Delivery vectors

• Fake software cracks, keygens, and torrent downloads
• Deceptive software update prompts on untrusted websites

Persistence mechanisms

• HKCU\Software\Microsoft\Windows\CurrentVersion\Run\AddropService
• Rogue browser extension registrations in Chrome and Edge

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_ADDROP_T1_ARTIFACT {
    meta:
        description = "Tier 1 Primitive Artifact: Raw string matches for Addrop"
        tier = "T1 - Primitive Artifact"
        confidence = "Low-Medium (Fast Triage)"
        author = "SystemHelpdesk Threat Research Desk"
        date = "2026-10-14"
    strings:
        $s1 = "addrop" ascii wide nocase
        $s2 = "adware:win32/addrop" ascii wide nocase
        $s3 = "adware.addrop" ascii wide nocase
        $s4 = "pua:win32/addrop" ascii wide nocase
        $s5 = "trojan.win32.addrop" ascii wide nocase
    condition:
        uint16(0) == 0x5a4d and any of them
}

title: SystemHelpDesk Detection - Addrop (Adware) Execution & Triage
id: 89b721cd-aeff-5125-82e2-d40797d7bff2
status: production
description: Detects execution, defense evasion, and persistence behaviors associated
  with the Addrop 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/addrop
- 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.adware
- author.ricky-jordan
- source.systemhelpdesk-mfc
- attack.t1204_002
- attack.t1176
- attack.t1112
- attack.t1562_001
- attack.t1027_002
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_ADDROP_T3_ATTRIBUTION {
    meta:
        description = "Tier 3 Attribution Fingerprint: Heuristic detection for Addrop 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 = "addrop" 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 initial dropper binary to prevent extraction of secondary advertising toolbars and extensions.
2. Deploy specialized adware removal tools (e.g., Malwarebytes AdwCleaner) to purge deep registry keys and scheduled tasks.
3. Reset all web browsers to default settings to remove rogue extensions, restore search engines, and clear tracking cookies.
4. Audit the Windows HOSTS file (C:\Windows\System32\drivers\etc\hosts) to ensure no security vendor domains are blocked.

What to Avoid

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

1. Do not rely solely on Windows Add/Remove Programs, as adware uninstallers frequently execute scripts to redownload components.
2. Avoid ignoring persistent adware infections, as tracking frameworks monitor user browsing behavior across sensitive portals.

References & External Analysis

• Malwarebytes Threat Intelligence - Adware.Addrop Detection
• Microsoft Defender Threat Encyclopedia - Adware:Win32/Addrop
• Search "addrop" on VirusTotal (External Analysis)
• Search "addrop" on Any.Run (Sandbox Sandbox)
• Search "addrop" on MalwareBazaar (Malware Samples)

Frequently Asked Questions

Related Threats (Category: Adware)

Explore other documented threats in the same operational category:

• Mywebsearch
• Rungbu
• Trymedia
• Mikey
• Convertad
• Bettersurf
• Mucc
• Temonde

Machine-readable

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