Napolar

Overview

Trojan:Win32/Napolar (also widely tracked as Solarbot) is a highly sophisticated banking trojan and botnet client that gained prominence around 2013. It is designed to establish deep persistence, steal financial credentials via web-injects (`T1185`), launch Distributed Denial of Service (DDoS) attacks, and function as a modular platform for downloading additional payloads. Its sophisticated evasion techniques made it highly effective against traditional antivirus solutions.

Understanding Napolar (Advanced Botnets)
To an end-user, a Napolar infection is entirely invisible. For a security operations center (SOC), it is a critical threat indicating a complete loss of endpoint integrity. Napolar isn't just a credential stealer; it effectively turns the compromised host into a node in a global cybercriminal infrastructure, capable of launching attacks against third parties.

Execution and Evasion Mechanics
Napolar was distributed via exploit kits (like Blackhole) or malspam (`T1566.001`). Its defining characteristic is its aggressive defense evasion. Upon execution, it performs deep process injection (`T1055`), often utilizing advanced API unhooking techniques to bypass user-land EDR sensors. It injects into `explorer.exe` and web browser processes (Chrome, Firefox, IE). Once hooked into the browser, it performs form-grabbing and web-injects (`T1185`) to steal banking credentials as they are typed. It communicates with a Tor-hosted C2 server or uses DGA (Domain Generation Algorithms) (`T1568.002`) to receive commands, which may include downloading massive executable files to participate in HTTP/UDP flood DDoS attacks (`T1498`).

Indicators of Compromise & Impact
The primary impact is the catastrophic theft of financial data and the endpoint being co-opted for DDoS operations. Host-based IoCs are subtle due to advanced injection, but memory analysis will reveal unsigned DLLs loaded into core system processes. EDR may catch anomalous API unhooking attempts. Network IoCs include the browser processes making unexpected connections to Tor exit nodes (if not configured to do so) or massive, sudden spikes in outbound UDP traffic indicative of a DDoS attack.

MITRE ATT&CK Techniques

Observed techniques used by this family, mapped to the MITRE ATT&CK framework:

Tactical Mitigations

Based on the techniques used by this family, consider the following defensive strategies:

• T1185: Enforce strong MFA and use browser isolation or hardened browsers for sensitive financial or administrative portals to defeat session hijacking.

Generated Detections (Boilerplate)

These YARA and Sigma rules are auto-generated based on the family name and aliases. They must be heavily tuned before deployment in a production environment.

YARA Rule

rule MALWARE_WIN_NAPOLAR {
    meta:
        description = "Detects Napolar (trojan)"
        author = "SystemHelpdesk Boilerplate Generator"
        date = "2026-07-06"
    strings:
        $s1 = "napolar" ascii wide nocase
    condition:
        uint16(0) == 0x5a4d and any of them
}

Sigma Rule

title: Suspicious Napolar Activity
id: 24b2f54ef0e03fa4da8fe55a5fdf87fb
status: experimental
description: Detects generic indicators of the napolar malware family.
logsource:
    category: process_creation
    product: windows
detection:
    selection:
        Image|endswith:
            - '\cmd.exe'
            - '\powershell.exe'
        CommandLine|contains:
            - "*napolar*"
    condition: selection
level: medium

Containment & Response Steps

Ordered checklist for responders. Adapt to your environment and engage professional support for active incidents.

1. Immediately isolate the compromised endpoint; a Napolar infection means the host is actively controlled by an advanced threat actor.
2. Do not attempt manual cleanup; the deep API hooks require a complete forensic wipe and operating system reinstallation.
3. Contact affected financial institutions to freeze accounts and reverse transactions, assuming all banking credentials have been compromised.
4. Analyze DNS logs for DGA-like requests to identify other potentially infected nodes on the enterprise network.

What to Avoid

Common mistakes during response to this family that can destroy evidence, spread the infection, or worsen recovery.

1. Do not trust the integrity of a system after a Napolar infection; its API unhooking capabilities render local AV scans unreliable.
2. Avoid relying solely on static IP blocking for the C2; the botnet utilizes DGA and Tor to maintain connectivity.

References & External Analysis

• Search "napolar" on VirusTotal (External Analysis)

Frequently Asked Questions

Related Families (Category: trojan)

Explore other malware families in the same category:

• Doser
• Optix
• Runbooster
• Dragonbot
• Inexsmar

Machine-readable

Get this profile as JSON: https://jordan123234-malware-families-explorer.static.hf.space/api/napolar.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.