Fakeinstaller
Table of Contents
Overview
Trojan:AndroidOS/Fakeinstaller is a massive, historically significant classification for a family of Android mobile malware designed to commit SMS Toll Fraud. These malicious applications masquerade as legitimate apps (like games, utilities, or even security software) on third-party app stores. Their sole purpose is to silently send premium-rate SMS text messages without the user's knowledge or consent, racking up massive charges on the victim's mobile phone bill.
Understanding Fakeinstaller (SMS Toll Fraud)
To an end-user, the infection often seems benign at first; the app might even provide the functionality it promised. However, the true impact is discovered weeks later when the mobile bill arrives. For a threat analyst, Fakeinstaller represents a highly lucrative, automated criminal enterprise that exploits the billing mechanics of mobile carriers.
Execution and Fraud Mechanics
Fakeinstaller is distributed primarily via unmoderated, third-party Android app stores or malicious links sent via SMS (Smishing). During installation, the crucial step occurs: the app requests the `SEND_SMS` Android permission. If granted, the malware activates upon installation or device boot (`RECEIVE_BOOT_COMPLETED`). It connects to a C2 server to retrieve a list of premium-rate shortcodes and the specific text strings required to trigger a billing event. It then silently sends these messages in the background (`T1624.001`). To evade detection by the user, many variants also utilize the `RECEIVE_SMS` permission to intercept and delete the confirmation texts sent back by the premium service, ensuring the victim remains unaware of the fraud.
Indicators of Compromise & Impact
The primary impact is direct financial loss via carrier billing. Device-based IoCs include the presence of applications requesting SMS permissions (`SEND_SMS`, `RECEIVE_SMS`, `READ_SMS`) that have no legitimate need for them (e.g., a flashlight app requesting SMS access). A review of the device's outbound SMS logs (if the malware hasn't deleted them) will reveal texts sent to unknown 5-digit or 6-digit shortcodes.
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-TR | Traffic Rate Limiting | Isolate | T1498 | Deploy BGP Flowspec and edge scrubbing proxies to automatically throttle volumetric SYN and UDP reflection attacks. |
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_FAKEINSTALLER_T1_ARTIFACT {
meta:
description = "Tier 1 Primitive Artifact: Raw string matches for Fakeinstaller"
tier = "T1 - Primitive Artifact"
confidence = "Low-Medium (Fast Triage)"
author = "SystemHelpdesk Threat Research Desk"
date = "2026-10-14"
strings:
$s1 = "fakeinstaller" 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 - Fakeinstaller (Trojan) Execution & Triage
id: 19fff95b-1b8a-5d03-9efb-5f0cb308fa73
status: production
description: Detects execution, defense evasion, and persistence behaviors associated
with the Fakeinstaller 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/fakeinstaller
- 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.t1437
- attack.t1498
- 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_FAKEINSTALLER_T3_ATTRIBUTION {
meta:
description = "Tier 3 Attribution Fingerprint: Heuristic detection for Fakeinstaller 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 = "fakeinstaller" 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.
- Immediately uninstall the suspicious application via the Android Settings > Apps menu.
- Contact the mobile carrier immediately to report the fraud, request a refund for the premium SMS charges, and place a block on all premium-rate billing.
- Review all installed applications and revoke SMS permissions from any app that does not strictly require it (like messaging apps).
- Consider performing a factory reset of the device if multiple malicious applications were installed.
What to Avoid
Common mistakes during response to this family that can destroy evidence, spread the infection, or worsen recovery.
- Do not allow users to 'sideload' applications (installing APKs from outside the official Google Play Store).
- Avoid blindly granting permissions during app installation; scrutinize why an app needs the access it requests.
References & External Analysis
- Search "fakeinstaller" on VirusTotal (External Analysis)
- Search "fakeinstaller" on Any.Run (Sandbox Sandbox)
- Search "fakeinstaller" on MalwareBazaar (Malware Samples)
Frequently Asked Questions
What is Fakeinstaller and what threat category does it belong to?
Fakeinstaller 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 Fakeinstaller establish persistence and evade defensive controls?
Fakeinstaller 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 Fakeinstaller compromise?
Security teams responding to Fakeinstaller 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 Fakeinstaller?
Fakeinstaller 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 Fakeinstaller across enterprise endpoints?
Defenders should hunt for Fakeinstaller 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 Fakeinstaller from Windows?
Manual removal of Fakeinstaller 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 Fakeinstaller infection?
Symptoms of Fakeinstaller 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 Fakeinstaller 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/fakeinstaller.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.