Scrop
Table of Contents
Overview
Scrop (cataloged across security vendors and threat intelligence databases under signatures including Trojan-Dropper:Win32/Scrop, Backdoor:Win32/Scrop, and Trojan.Win32.Scrop) is a stealthy Windows trojan dropper and initial access framework active since 2017. Propagated primarily through malicious email attachments, cracked software utilities, and drive-by downloads, Scrop serves as an evasion-focused loader designed to securely deploy secondary malware payloads such as banking trojans, information stealers, and remote access backdoors. Upon execution, Scrop establishes persistence via Windows Startup scripts (such as xcutes.exe.vbs) and scheduled tasks. To bypass host security controls and static antivirus signatures, Scrop leverages process injection into trusted native utilities like RegAsm.exe or svchost.exe, executing its decrypted payload in memory while establishing encrypted outbound C2 beacons.
Known aliases
Threat reports may refer to this family under multiple names:
Family Pedigree & Lineage
Malware authors regularly fork and iterate upon existing codebases. Observed upstream lineage and downstream variants for this family include:
Known Derivatives & Downstream Variants: Trojan-Dropper:Win32/Scrop.A · Backdoor:Win32/Scrop!Rfn
MITRE ATT&CK Techniques
This family has been observed using the following ATT&CK techniques: T1055 · T1059.005 · T1547.001 · T1105 · T1071.001 · T1082
Tactical Mitigations
Based on the techniques used by this family, consider the following defensive strategies:
- T1059.005: Restrict execution of scripting languages such as PowerShell, VBScript, or Python to authorized administrators. Enforce Script Block Logging.
- 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):
| D3FEND ID | Countermeasure Name | Tactic | Countered ATT&CK | Defensive Guidance |
|---|---|---|---|---|
D3-PIAD | Process Injection Analysis & Detection | Detect | T1055 | Monitor cross-process thread creation (CreateRemoteThread) and asynchronous procedure calls (QueueUserAPC). |
D3-SEA | Script Execution Analysis | Detect | T1059.005 | Analyze script block syntax and command arguments at runtime to detect malicious automation. |
D3-WAF | Web Content Filtering & Inspection | Filter | T1071.001 | Block newly registered domains (NRDs) and inspect HTTP Host and URI headers for known C2 profiles. |
D3-SDA | System Discovery Analysis | Detect | T1082 | Alert on rapid enumerations of systeminfo, hostname, and registry hardware trees in short intervals. |
D3-NTI | Network Traffic Inspection | Detect | T1105 | Inspect deep packet payloads for anomalous staging binaries and unauthorized egress protocols. |
D3-RPM | Registry Persistence Monitoring | Detect | T1547.001 | Audit and restrict write privileges to user and machine-level Registry Run/RunOnce keys using Endpoint Privilege Management. |
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:
Tier 1 Primitive Artifact Rule (Fast Triage)
Matches raw strings and file markers. Vulnerable to binary repacking and simple obfuscation.
rule MALWARE_WIN_SCROP_T1_ARTIFACT {
meta:
description = "Tier 1 Primitive Artifact: Raw string matches for Scrop"
tier = "T1 - Primitive Artifact"
confidence = "Low-Medium (Fast Triage)"
author = "SystemHelpdesk Threat Research Desk"
date = "2026-10-14"
strings:
$s1 = "scrop" ascii wide nocase
$s2 = "trojan-dropper:win32/scrop" ascii wide nocase
$s3 = "backdoor:win32/scrop" ascii wide nocase
$s4 = "trojan.win32.scrop" ascii wide nocase
$s5 = "win32/scrop" ascii wide nocase
$s6 = "dropper.win32.scrop" ascii wide nocase
condition:
uint16(0) == 0x5a4d and any of them
}Tier 2 Behavioral Context Rule (Process Chains & Sigma)
Tracks parent-child process anomalies and suspicious scripting telemetry. Resilient against file renames.
title: SystemHelpDesk Detection - Scrop (Trojan Downloader) Execution & Triage
id: b66eba64-cdad-54ac-85a3-11584776ac0a
status: production
description: Detects execution, defense evasion, and persistence behaviors associated
with the Scrop 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/scrop
- 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.trojan-downloader
- author.ricky-jordan
- source.systemhelpdesk-mfc
- attack.t1055
- attack.t1059_005
- attack.t1547_001
- attack.t1105
- attack.t1071_001
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: mediumTier 3 Attribution Fingerprint Rule (High Fidelity)
Deep signature matching distinctive operational fingerprints and payload characteristics.
rule MALWARE_WIN_SCROP_T3_ATTRIBUTION {
meta:
description = "Tier 3 Attribution Fingerprint: Heuristic detection for Scrop 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 = "scrop" 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
}References & External Analysis
- Trend Micro Threat Encyclopedia - Trojan.Win32.Scrop
- Search "scrop" on VirusTotal (External Analysis)
- Search "scrop" on Any.Run (Sandbox Sandbox)
- Search "scrop" on MalwareBazaar (Malware Samples)
Frequently Asked Questions
What is Trojan-Dropper:Win32/Scrop?
Scrop is a stealthy Windows trojan dropper and loader designed to deliver secondary malicious payloads without detection.
How does Scrop evade endpoint antivirus defenses?
It injects decrypted shellcode directly into legitimate Windows binaries like RegAsm.exe and svchost.exe.
How does Scrop establish persistence on the infected host?
It drops VBScript startup files (like xcutes.exe.vbs) and schedules recurring tasks to maintain execution after reboots.
What secondary payloads are typically dropped by Scrop?
It commonly delivers infostealers, banking trojans, keyloggers, and persistent remote access backdoors.
How can defenders remediate a Scrop infection?
Perform a Microsoft Defender Offline scan, terminate injected processes, and audit the Startup folder for malicious VBS scripts.
How do I remove the Scrop Trojan_Downloader from Windows?
Manual removal of Scrop is highly discouraged as it may leave persistence mechanisms intact. We recommend disconnecting the device from the internet and utilizing a professional incident response service or enterprise-grade EDR software to conduct a full forensic sweep.
Is Scrop a virus or a Trojan_Downloader?
Scrop is classified as a Trojan_Downloader. Unlike traditional viruses that infect files, modern malware like Scrop typically operates as a standalone payload designed to compromise systems, steal data, or deploy secondary stage implants.
What are the main symptoms of a Scrop infection?
Symptoms of Scrop can include unexpected system slowness, unauthorized outbound network traffic to unknown IP addresses, disabled security software, and suspicious background processes running from AppData or Temp directories.
Protect Your Network Against Trojan_Downloaders
Want to prevent Scrop and similar threats from compromising your organization? Read our comprehensive defensive guide: Banking Trojan Protection for Businesses.
📣 Threat Intel Correction or Update?
Notice an outdated IOC, unlisted alias, or disputed attribution? Threat researchers are invited to propose an update on GitHub or contact the SystemHelpDesk research desk. All community revisions are credited in our public CHANGELOG.
Machine-readable
Get this profile as JSON: https://malware-families-catalog.systemhelpdesk.com/api/scrop.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.