Tasker
Table of Contents
Overview
Tasker (identified across endpoint security databases and threat intelligence reports as Trojan:Win32/Tasker, Backdoor:Win32/Tasker, and Trojan.Tasker) is a stealthy Windows trojan and initial access backdoor active since 2017 that specializes in abusing the native Windows Task Scheduler subsystem. Infiltrating environments via weaponized spear-phishing emails or cracked software installers, Tasker leverages the Task Scheduler API (ITaskService COM interfaces or schtasks.exe) to create obfuscated, high-privilege scheduled tasks disguised under names of legitimate operating system tasks (such as Windows Defender updates or disk optimization routines). Through these scheduled triggers, Tasker maintains resilient persistence that survives system reboots, establishes encrypted HTTP/HTTPS command-and-control communication, performs endpoint surveillance, and periodically downloads secondary ransomware or infostealer modules.
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:Win32/Tasker.A · Trojan:Win32/Tasker.B
MITRE ATT&CK Techniques
This family has been observed using the following ATT&CK techniques: T1053.005 · T1071.001 · T1055 · T1036.005 · T1082
Tactical Mitigations
Based on the techniques used by this family, consider the following defensive strategies:
- T1036.005: Monitor for executable files running from unusual paths or with deceptive names. Use EDR to detect process masquerading.
- T1071.001: Implement web filtering and SSL/TLS inspection to detect malicious command and control (C2) traffic hiding in HTTP/HTTPS.
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-PMA | Process Lineage & Masquerade Analysis | Detect | T1036.005 | Verify digital code-signing signatures and compare executable paths against known Windows binaries. |
D3-STM | Scheduled Task Creation Analysis | Detect | T1053.005 | Audit task creation targeting system and hidden service directories; verify task author credentials. |
D3-PIAD | Process Injection Analysis & Detection | Detect | T1055 | Monitor cross-process thread creation (CreateRemoteThread) and asynchronous procedure calls (QueueUserAPC). |
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. |
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_TASKER_T1_ARTIFACT {
meta:
description = "Tier 1 Primitive Artifact: Raw string matches for Tasker"
tier = "T1 - Primitive Artifact"
confidence = "Low-Medium (Fast Triage)"
author = "SystemHelpdesk Threat Research Desk"
date = "2026-10-14"
strings:
$s1 = "tasker" ascii wide nocase
$s2 = "trojan:win32/tasker" ascii wide nocase
$s3 = "backdoor:win32/tasker" ascii wide nocase
$s4 = "trojan.tasker" ascii wide nocase
$s5 = "win32/tasker" ascii wide nocase
$s6 = "trojan:win32/tasker.a" 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 - Tasker (Trojan) Execution & Triage
id: 469d035e-6561-5311-9a0d-03c5f5babf8b
status: production
description: Detects execution, defense evasion, and persistence behaviors associated
with the Tasker 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/tasker
- 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.t1053_005
- attack.t1071_001
- attack.t1055
- attack.t1036_005
- attack.t1082
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_TASKER_T3_ATTRIBUTION {
meta:
description = "Tier 3 Attribution Fingerprint: Heuristic detection for Tasker 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 = "tasker" 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
- Microsoft Defender Threat Encyclopedia - Trojan:Win32/Tasker
- MITRE ATT&CK - Technique T1053.005 Scheduled Task
- Search "tasker" on VirusTotal (External Analysis)
- Search "tasker" on Any.Run (Sandbox Sandbox)
- Search "tasker" on MalwareBazaar (Malware Samples)
Frequently Asked Questions
What is Trojan:Win32/Tasker?
Tasker is a Windows trojan and backdoor that establishes persistence and executes malicious code by creating deceptive Windows Scheduled Tasks.
How does Tasker abuse the Windows Task Scheduler?
It interfaces with the ITaskService API to register recurring tasks masquerading as legitimate Windows maintenance routines, executing with SYSTEM privileges.
What capabilities does Tasker possess once active?
Tasker provides remote command execution, captures host system information, and downloads secondary payloads such as ransomware and infostealers.
How can defenders detect malicious scheduled tasks created by Tasker?
Monitor Windows Security Event ID 4698 (A scheduled task was created) and inspect the TaskCache registry keys for unregistered or disguised task entries.
What remediation steps are required for a Tasker infection?
Delete unauthorized scheduled tasks using schtasks /delete, remove malicious startup registry keys, terminate injected processes, and run a complete malware scan.
How do I remove the Tasker Trojan from Windows?
Manual removal of Tasker 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 Tasker a virus or a Trojan?
Tasker is classified as a Trojan. Unlike traditional viruses that infect files, modern malware like Tasker typically operates as a standalone payload designed to compromise systems, steal data, or deploy secondary stage implants.
What are the main symptoms of a Tasker infection?
Symptoms of Tasker 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 Tasker 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/tasker.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.