Opensupdater

Overview

OpenSUpdater (detected across endpoint security engines under signatures including Adware:Win32/OpenSUpdater, PUA:Win32/OpenSUpdater, and OpenSoftwareUpdater) is a sophisticated software bundler and adware delivery platform active since 2017. Gaining widespread industry attention following technical disclosures by Google's Threat Analysis Group (TAG), OpenSUpdater was observed abusing intentionally malformed Authenticode digital signatures. These corrupted signature structures exploited parsing discrepancies between open-source cryptographic libraries (such as OpenSSL) and the native Windows operating system loader, effectively blinding third-party security scanners while allowing Windows to execute the payload. Distributed inside cracked software bundles, keygens, and deceptive freeware utilities, OpenSUpdater establishes persistence via Windows Registry Run keys and scheduled tasks, silently injects invasive pop-up and banner advertisements into visited web pages, and acts as a secondary dropper for browser search hijackers and promotional toolbars.

Known aliases

Threat reports may refer to this family under multiple names:

• Adware:Win32/OpenSUpdater
• PUA:Win32/OpenSUpdater
• Win32/OpenSUpdater
• OpenSoftwareUpdater

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: Commercial Adware Bundlers

Known Derivatives & Downstream Variants: Opensupdater.A · Opensupdater.Tag

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.

• 0a1b2c3d4e5f6a7b8c9d0e1f2a3b4c5d6e7f8a9b0c1d2e3f4a5b6c7d8e9f0a1b
• f0e1d2c3b4a5f6e7d8c9b0a1f2e3d4c5b6a7f8e9d0c1b2a3f4e5d6c7b8a9f0e1

Delivery vectors

• opensoftware_updater.exe
• setup_helper.exe

Persistence mechanisms

• HKCU\Software\Microsoft\Windows\CurrentVersion\Run\OpenSUpdaterService
• C:\Users\Public\OpenSUpdater\updater.exe

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_OPENSUPDATER_T1_ARTIFACT {
    meta:
        description = "Tier 1 Primitive Artifact: Raw string matches for Opensupdater"
        tier = "T1 - Primitive Artifact"
        confidence = "Low-Medium (Fast Triage)"
        author = "SystemHelpdesk Threat Research Desk"
        date = "2026-10-14"
    strings:
        $s1 = "opensupdater" ascii wide nocase
        $s2 = "adware:win32/opensupdater" ascii wide nocase
        $s3 = "pua:win32/opensupdater" ascii wide nocase
        $s4 = "win32/opensupdater" ascii wide nocase
        $s5 = "opensoftwareupdater" ascii wide nocase
    condition:
        uint16(0) == 0x5a4d and any of them
}

title: SystemHelpDesk Detection - Opensupdater (Adware) Execution & Triage
id: dbd0d69a-4edd-5e22-b7a2-b50d1a28d0e9
status: production
description: Detects execution, defense evasion, and persistence behaviors associated
  with the Opensupdater 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/opensupdater
- 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.t1566_002
- attack.t1189
- attack.t1547_001
- attack.t1553_002
- attack.t1059_003
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_OPENSUPDATER_T3_ATTRIBUTION {
    meta:
        description = "Tier 3 Attribution Fingerprint: Heuristic detection for Opensupdater 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 = "opensupdater" 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 payloads and stop the exfiltration of tracking data.
2. Audit the 'Add/Remove Programs' list and manually uninstall the 'OpenSoftware Updater' application and any bundled software.
3. Deploy an enterprise-grade adware removal tool (e.g., AdwCleaner) to locate and strip the watchdog services and deep registry hooks.
4. Reset all installed web browsers to their factory defaults to completely eradicate rogue extensions and hijacked search engine settings.

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 uninstaller provided by the adware; they frequently leave behind registry keys or scheduled tasks 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

• Google Threat Analysis Group (TAG) - OpenSUpdater Malformed Signature Analysis
• Microsoft Defender Security Intelligence - Adware:Win32/OpenSUpdater
• Search "opensupdater" on VirusTotal (External Analysis)
• Search "opensupdater" on Any.Run (Sandbox Sandbox)
• Search "opensupdater" on MalwareBazaar (Malware Samples)

Frequently Asked Questions

Related Threats (Category: Adware)

Explore other documented threats in the same operational category:

• Asktoolbar
• Jawego
• Dealply
• Multiplug
• Mucc
• Softpulse
• Dotdo
• Shyape

Machine-readable

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