Addrop

Overview

Adware:Win32/Addrop is a deceptive adware dropper program explicitly designed to silently install multiple Potentially Unwanted Programs (PUPs), browser hijackers, and intrusive advertising frameworks onto a victim's machine.

What is Addrop?
To the average user, Addrop causes severe browser degradation, unexpected pop-ups, and the sudden appearance of unknown applications. For security analysts, Addrop represents a persistent nuisance and a compliance risk. Unlike a traditional downloader that fetches payloads from the internet, a 'dropper' (like Addrop) typically contains the secondary adware payloads compressed or encrypted within its own executable file, dropping them directly onto the disk upon execution.

Infection Vectors & Threat Hunting
Addrop is primarily distributed via fake software cracks, keygens, or deceptive downloads posing as legitimate media players on untrusted sites. Upon execution, the user may see a fake installation screen while Addrop silently extracts its payload of adware to the `%ProgramFiles%` or `%AppData%` directories. It establishes persistence by modifying the Windows Registry (`HKCU\Software\Microsoft\Windows\CurrentVersion\Run`) and drops browser extensions that hijack search queries to affiliate portals. Addrop may also alter the Windows HOSTS file to block access to security vendor websites.

Forensic Analysis & Impact
Threat hunters will observe the initial Addrop executable dropping numerous files to disk in rapid succession without network activity (as the payloads are embedded). Once the adware is active, a massive spike in outbound HTTP/HTTPS connections to affiliate tracking domains will occur. The impact is a severely bloated endpoint, compromised search privacy, and potential system instability due to conflicting toolbars.

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

Sigma Rule

title: Suspicious Addrop Activity
id: f92370867905a596669aac0a245625ea
status: experimental
description: Detects generic indicators of the addrop malware family.
logsource:
    category: process_creation
    product: windows
detection:
    selection:
        Image|endswith:
            - '\cmd.exe'
            - '\powershell.exe'
        CommandLine|contains:
            - "*addrop*"
    condition: selection
level: medium

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 active adware tracking and prevent the potential downloading of further malicious updates.
2. Deploy specialized adware removal tools (like AdwCleaner) to locate and strip the forced Group Policies, Windows Services, and deep registry hooks dropped by Addrop.
3. Reset all web browsers to their factory defaults to completely purge the rogue extensions and restore legitimate search settings.
4. Audit the Windows HOSTS file and revert any unauthorized entries blocking access to security vendors.

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 dropped adware; they frequently execute secondary scripts to reinstall the software later.
2. Avoid ignoring the infection; the tracking infrastructure actively harvests browsing habits, which may include access to sensitive corporate portals.

References & External Analysis

• Search "addrop" on VirusTotal (External Analysis)

Frequently Asked Questions

Related Families (Category: advanced_threat)

Explore other malware families in the same category:

• Searchsetter
• Cntads
• Drmsoft
• Netstream
• Vidarstealer

Machine-readable

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