Dyloader
Table of Contents
Overview
Trojan:AndroidOS/Dyloader is a mobile banking trojan targeting the Android operating system. Unlike Windows-based banking trojans that rely on web injects, Dyloader represents the mobile-centric approach to financial theft: it utilizes deceptive Overlay Attacks (`T1636`) to steal credentials and aggressively abuses Android Accessibility Services (`T1628`) to intercept multi-factor authentication (MFA) SMS messages.
Understanding Dyloader (Android Banking Trojans)
To a mobile user, Dyloader typically masquerades as a legitimate application—often a utility app (like a PDF reader or Flash player) downloaded from a third-party app store or pushed via a phishing SMS (Smishing). For a threat analyst, Dyloader is a highly interactive threat where the attacker monitors the device in real-time, waiting for the user to open a targeted banking application.
Execution and Credential Theft Mechanics
Once installed, Dyloader immediately requests extensive permissions, most critically asking the user to enable Accessibility Services (`T1628`). With Accessibility enabled, the trojan gains near-total control over the device UI. When the user launches a targeted banking app, Dyloader detects the app launch and instantly draws a fake login screen *over* the legitimate app (`T1636`). The user unwittingly enters their credentials into the malware's overlay. The trojan then leverages its Accessibility permissions to silently read incoming SMS messages (`T1624.001`), capturing the bank's OTP/MFA codes and sending them to the attacker's C2 server to complete the fraudulent transaction.
Indicators of Compromise & Impact
The impact is direct financial theft and full compromise of the user's mobile banking identity. Device-based IoCs include applications requesting Accessibility Services that have no legitimate need for them (e.g., a 'Flashlight' app requesting screen reading permissions). A key behavioral indicator is a slight delay or 'flicker' when opening a banking application, signifying the overlay being drawn. Network IoCs include the device maintaining a constant heartbeat connection to an unknown C2 server via HTTPS.
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):
| D3FEND ID | Countermeasure Name | Tactic | Countered ATT&CK | Defensive Guidance |
|---|---|---|---|---|
D3-MFA | Hardware Security Key Authentication | Harden | T1628 | Replace insecure SMS one-time passwords with hardware-backed security keys or authenticator push tokens. |
D3-SCA | Segmented Cloud Storage Access | Isolate | T1636 | Enforce strict IAM service account policies and VPC Service Controls to prevent staging of sensitive data to unapproved cloud buckets. |
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_DYLOADER_T1_ARTIFACT {
meta:
description = "Tier 1 Primitive Artifact: Raw string matches for Dyloader"
tier = "T1 - Primitive Artifact"
confidence = "Low-Medium (Fast Triage)"
author = "SystemHelpdesk Threat Research Desk"
date = "2026-10-14"
strings:
$s1 = "dyloader" 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 - Dyloader (Trojan) Execution & Triage
id: 9c3f6bf5-8824-5787-a114-99f7cdc01783
status: production
description: Detects execution, defense evasion, and persistence behaviors associated
with the Dyloader 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/dyloader
- 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.t1636
- attack.t1628
- attack.t1479
- attack.t1624_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_DYLOADER_T3_ATTRIBUTION {
meta:
description = "Tier 3 Attribution Fingerprint: Heuristic detection for Dyloader 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 = "dyloader" 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.
- Boot the Android device into 'Safe Mode' (which disables third-party apps) to bypass the trojan's UI blocks.
- Navigate to `Settings -> Accessibility` and immediately revoke Accessibility permissions from the suspicious application.
- Go to `Settings -> Apps` and manually uninstall the malicious application.
- Contact the affected financial institutions immediately to freeze accounts and report the compromised MFA tokens.
What to Avoid
Common mistakes during response to this family that can destroy evidence, spread the infection, or worsen recovery.
- Do not blindly grant Accessibility Services to applications; this is the most dangerous permission in the Android ecosystem.
- Avoid downloading applications from untrusted third-party app stores or side-loading APKs sent via SMS.
References & External Analysis
- Search "dyloader" on VirusTotal (External Analysis)
- Search "dyloader" on Any.Run (Sandbox Sandbox)
- Search "dyloader" on MalwareBazaar (Malware Samples)
Frequently Asked Questions
What is Dyloader and what threat category does it belong to?
Dyloader is classified as a Trojan. Documented across security telemetry, it is engineered to execute unauthorized operations, establish persistent footholds on target endpoints, and facilitate malicious campaigns targeting enterprise and individual environments.
How does Dyloader establish persistence and evade defensive controls?
Dyloader typically establishes persistence through registry run keys, scheduled tasks, or service installations, while evading signature-based antivirus solutions through code obfuscation, memory injection, or anti-analysis sandbox checks.
What are the essential incident response steps for mitigating a Dyloader compromise?
Security teams responding to Dyloader should immediately isolate affected endpoints from the network, perform memory triage to capture volatile forensic artifacts, audit registry and startup persistence mechanisms, revoke exposed user credentials, and restore systems from verified, clean backups.
What secondary payloads and staging behaviors are commonly associated with Dyloader?
Dyloader frequently operates as a loader or dropper designed to establish a foothold before downloading and executing secondary high-impact malware payloads. Depending on the threat actor's objectives, these dropped modules can range from ransomware and banking injects to modular infostealers and remote management backdoors.
How can security operations teams effectively detect and hunt for Dyloader across enterprise endpoints?
Defenders should hunt for Dyloader by deploying behavioral endpoint detection and response (EDR) rules that monitor suspicious process spawning (such as cmd.exe or powershell.exe spawned from office documents or temporary directories), anomalous outbound network connections from non-browser binaries, and unauthorized modifications to Windows Run keys and scheduled task registries.
How do I remove Dyloader from Windows?
Manual removal of Dyloader 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.
What are the main symptoms of a Dyloader infection?
Symptoms of Dyloader 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 Trojans
Want to prevent Dyloader 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/dyloader.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.