Pullupdate
Table of Contents
Overview
Adware:Win32/Pullupdate is a persistent component often associated with larger Potentially Unwanted Program (PUA) or Adware frameworks. Its primary function is to act as a silent, background updater service. Rather than delivering a payload itself, Pullupdate ensures that any previously installed adware extensions, browser hijackers, or tracking modules on the endpoint are constantly refreshed, overriding any user attempts to remove or disable them.
Understanding Pullupdate Mechanisms
To an end-user, Pullupdate is entirely invisible; it doesn't display windows or generate errors. However, users will notice that rogue browser extensions (like 'Search Protect' or various coupon clippers) miraculously reappear after being deleted. For a security analyst, Pullupdate is a persistence mechanism (`T1547.001`). It is the 'watchdog' that guarantees the adware developers maintain their foothold on the system to continue generating illicit affiliate revenue.
Execution and Persistence
Pullupdate is installed silently alongside bundled freeware (`T1189`). It immediately registers itself as a Windows Service (`T1543.003`) or creates a scheduled task (`T1053.005`) that runs with SYSTEM privileges upon boot. Once active, it periodically reaches out to its Command-and-Control (C2) servers (`T1071.001`). It downloads the latest versions of the adware binaries and rogue browser extension `.crx` files. If it detects that the adware has been removed from the browser or the registry, it silently reinstalls it (`T1176`), effectively undoing the user's remediation efforts.
Indicators of Compromise & Impact
The primary impact is the inability to permanently remove adware, leading to continuous browser hijacking and privacy violations. IoCs include EDR alerts for the creation of unexpected Scheduled Tasks pointing to obscure executables in the `%AppData%` or `%ProgramData%` directories. Network logs will show rhythmic, beaconing HTTP/HTTPS traffic to known PUA infrastructure, often downloading signed, but suspicious, payload files.
MITRE ATT&CK Techniques
Observed techniques used by this family, mapped to our technical analysis hubs and the official MITRE ATT&CK framework:
| Technique | Name | Tactic | Official Spec |
|---|---|---|---|
T1543.003 | Create or Modify System Process: Windows Service (Updater service) | Persistence | ATT&CK ↗ |
T1053.005 | Scheduled Task/Job: Scheduled Task | Persistence | ATT&CK ↗ |
T1176 | Browser Extensions (Reinstalling rogue extensions) | Persistence | ATT&CK ↗ |
T1189 | Drive-by Compromise (Initial delivery) | Initial Access | ATT&CK ↗ |
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-STM | Scheduled Task Creation Analysis | Detect | T1053.005 | Audit task creation targeting system and hidden service directories; verify task author credentials. |
D3-BEA | Browser Extension Allowlisting | Harden | T1176 | Deploy enterprise browser policies via GPO or Intune to block unauthorized side-loaded extensions and add-ons. |
D3-RBI | Remote Browser Isolation | Isolate | T1189 | Execute untrusted web browsing sessions in disposable cloud containers to isolate drive-by exploits from local endpoints. |
D3-SCM | Windows Service Creation Monitoring | Detect | T1543.003 | Verify service binary image signatures and restrict standard users from creating or modifying service definitions. |
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_PULLUPDATE_T1_ARTIFACT {
meta:
description = "Tier 1 Primitive Artifact: Raw string matches for Pullupdate"
tier = "T1 - Primitive Artifact"
confidence = "Low-Medium (Fast Triage)"
author = "SystemHelpdesk Threat Research Desk"
date = "2026-10-14"
strings:
$s1 = "pullupdate" 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 - Pullupdate (Advanced Threat) Execution & Triage
id: cf63a82c-d805-577f-b670-1b470de88b99
status: production
description: Detects execution, defense evasion, and persistence behaviors associated
with the Pullupdate malware family. Detects proxy execution, reflective DLL loading,
and remote command injection associated with modular enterprise backdoors.
references:
- https://malware-families-catalog.systemhelpdesk.com/families/pullupdate
- https://malware-families-catalog.systemhelpdesk.com/defensive/backdoor-rat-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.advanced-threat
- author.ricky-jordan
- source.systemhelpdesk-mfc
- attack.t1543_003
- attack.t1176
- attack.t1053_005
- attack.t1189
logsource:
category: process_creation
product: windows
detection:
selection_process:
Image|endswith:
- \powershell.exe
- \cmd.exe
- \rundll32.exe
- \regsvr32.exe
CommandLine|contains:
- DownloadString
- IEX(
- '/s /n /u /i:'
- sc create
- start-process
condition: selection_process
falsepositives:
- Legitimate enterprise administrative scripts during approved change windows
- Authorized IT software deployment utilities and backup management agents
level: highTier 3 Attribution Fingerprint Rule (High Fidelity)
Deep signature matching distinctive operational fingerprints and payload characteristics.
rule MALWARE_WIN_PULLUPDATE_T3_ATTRIBUTION {
meta:
description = "Tier 3 Attribution Fingerprint: Heuristic detection for Pullupdate 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 = "pullupdate" 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.
- Do not simply delete the adware extension from the browser; you must first locate and neutralize the Pullupdate service or task, otherwise the extension will return on reboot.
- Audit the Windows Task Scheduler (`taskschd.msc`) and Services (`services.msc`) for entries created around the time the adware first appeared.
- Deploy an enterprise-grade PUA removal tool (like AdwCleaner) to surgically remove the updater service and all associated registry keys.
- Block the known C2 domains associated with the adware family at the perimeter firewall to prevent the updater from downloading fresh payloads.
What to Avoid
Common mistakes during response to this family that can destroy evidence, spread the infection, or worsen recovery.
- Avoid assuming manual deletion of a file fixes the problem; updater components are specifically designed to survive basic deletion attempts.
- Do not ignore recurring adware alerts from the same machine; it indicates the underlying updater mechanism is still active.
References & External Analysis
- Search "pullupdate" on VirusTotal (External Analysis)
- Search "pullupdate" on Any.Run (Sandbox Sandbox)
- Search "pullupdate" on MalwareBazaar (Malware Samples)
Frequently Asked Questions
What is Pullupdate and what threat category does it belong to?
Pullupdate is classified as a Advanced Threat. 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 Pullupdate establish persistence and evade defensive controls?
Pullupdate 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 Pullupdate compromise?
Security teams responding to Pullupdate 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 lateral movement and credential access tactics does Pullupdate leverage in enterprise intrusions?
Pullupdate frequently utilizes privileged account harvesting techniques such as LSASS memory dumping, Kerberoasting, and token impersonation to escalate privileges. Once administrative credentials are acquired, it pivots across the victim network utilizing living-off-the-land binaries (LOLBins) such as WMI, PowerShell remoting, and PsExec, or abuses remote desktop protocols (RDP) to reach critical internal repositories and domain controllers.
How does Pullupdate maintain covert communications and evade perimeter network monitoring?
Pullupdate often relies on multi-stage command and control (C2) architectures utilizing encrypted protocols over standard web ports (HTTPS/443 or DNS tunneling) to blend in with legitimate enterprise network traffic. Many variants incorporate proxy networks, domain fronting, or cloud services (such as Microsoft Graph API, Google Drive, or Telegram) to masquerade C2 channels, bypassing traditional signature-based egress filtering.
How do I remove the Pullupdate Advanced_Threat from Windows?
Manual removal of Pullupdate 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 Pullupdate a virus or a Advanced_Threat?
Pullupdate is classified as a Advanced_Threat. Unlike traditional viruses that infect files, modern malware like Pullupdate typically operates as a standalone payload designed to compromise systems, steal data, or deploy secondary stage implants.
What are the main symptoms of a Pullupdate infection?
Symptoms of Pullupdate 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 Advanced_Threats
Want to prevent Pullupdate and similar threats from compromising your organization? Read our comprehensive defensive guide: Think You've Been Hacked? What To Do First.
📣 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/pullupdate.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.