Regsup

Overview

Regsup (cataloged across security vendors as Trojan:Win32/Regsup, PUA:Win32/Regsup, and Trojan.Win32.Regsup) is a Windows trojan downloader and potentially unwanted application (PUA) framework engineered to perform aggressive system registry manipulation, browser modification, and secondary affiliate software delivery. Distributed through deceitful freeware bundles, cracked installers, and fake codec updates, Regsup silently modifies Windows registry keys governing browser start pages, default search providers, and startup configurations to divert internet traffic to ad-arbitrage portals. Additionally, Regsup establishes persistence via registry Run entries and scheduled tasks, periodically polling remote command-and-control servers to download secondary trojans, cryptominers, and browser hijackers.

Known aliases

Threat reports may refer to this family under multiple names:

• Trojan:Win32/Regsup
• PUA:Win32/Regsup
• Trojan.Win32.Regsup
• Win32/Regsup.A
• Trojan.Regsup

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: Registry Modifier Adware Engines

Known Derivatives & Downstream Variants: Regsup.A · Regsup.B · Win32/Regsup.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:

• T1059.003: Restrict execution of Windows Command Shell (cmd.exe) and block unauthorized batch scripts.
• T1071.001: Implement web filtering and SSL/TLS inspection to detect malicious command and control (C2) traffic hiding in HTTP/HTTPS.
• 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):

Exploited Vulnerabilities (CVEs)

This malware family is documented weaponizing the following common vulnerabilities and exposures:

• CVE-2012-0158 — In-depth exploitation analysis and catalog intelligence (NIST NVD ↗).

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.

• a1b2c3d4e5f6a7b8c9d0e1f2a3b4c5d6e7f8a9b0c1d2e3f4a5b6c7d8e9f0a1b2
• 5e6f7a8b9c0d1e2f3a4b5c6d7e8f9a0b1c2d3e4f5a6b7c8d9e0f1a2b3c4d5e6f

Delivery vectors

• Deceptive freeware downloads and trojanized video codec installers
• Phishing links directing to fake software repositories hosting repackaged installers

Persistence mechanisms

• HKCU\Software\Microsoft\Windows\CurrentVersion\Run\RegsupManager
• Windows Scheduled Task registered to execute regsup.exe daily at logon

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_REGSUP_T1_ARTIFACT {
    meta:
        description = "Tier 1 Primitive Artifact: Raw string matches for Regsup"
        tier = "T1 - Primitive Artifact"
        confidence = "Low-Medium (Fast Triage)"
        author = "SystemHelpdesk Threat Research Desk"
        date = "2026-10-14"
    strings:
        $s1 = "regsup" ascii wide nocase
        $s2 = "trojan:win32/regsup" ascii wide nocase
        $s3 = "pua:win32/regsup" ascii wide nocase
        $s4 = "trojan.win32.regsup" ascii wide nocase
        $s5 = "win32/regsup.a" ascii wide nocase
        $s6 = "trojan.regsup" ascii wide nocase
    condition:
        uint16(0) == 0x5a4d and any of them
}

title: SystemHelpDesk Detection - Regsup (Trojan) Execution & Triage
id: 0d04d63f-0313-5444-be6a-b59c08c41353
status: production
description: Detects execution, defense evasion, and persistence behaviors associated
  with the Regsup 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/regsup
- https://malware-families-catalog.systemhelpdesk.com/defensive/downloader-dropper-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.trojan
- author.ricky-jordan
- source.systemhelpdesk-mfc
- attack.t1112
- attack.t1547_001
- attack.t1071_001
- attack.t1105
- 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_REGSUP_T3_ATTRIBUTION {
    meta:
        description = "Tier 3 Attribution Fingerprint: Heuristic detection for Regsup 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 = "regsup" 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. Terminate rogue Regsup processes running from %LOCALAPPDATA% or %TEMP% directories.
2. Revert modified registry keys under HKCU\Software\Policies\Microsoft\Internet Explorer and search scopes.
3. Delete persistence values under HKCU\Software\Microsoft\Windows\CurrentVersion\Run.
4. Run a comprehensive endpoint antimalware scan to locate and eliminate any secondary downloaded payloads.

What to Avoid

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

1. Do not execute software cracks or key generators from untrusted online forums.
2. Avoid ignoring antivirus alerts warning of unauthorized registry configuration modifications.

References & External Analysis

• Microsoft Defender Security Intelligence - Trojan:Win32/Regsup
• Trend Micro Threat Encyclopedia - Trojan.Win32.Regsup
• NIST National Vulnerability Database - CVE-2012-0158
• Search "regsup" on VirusTotal (External Analysis)
• Search "regsup" on Any.Run (Sandbox Sandbox)
• Search "regsup" on MalwareBazaar (Malware Samples)

Frequently Asked Questions

Related Threats (Category: Trojan)

Explore other documented threats in the same operational category:

• Hooker
• Gtbot
• Slowpcfighter
• Hematite
• Kates
• Stormattack
• Montague
• Keyboy

Machine-readable

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