Removal instructions for the Astaroth trojan-type malware

What kind of malware is Astaroth?

Astaroth is high-risk trojan-type virus. It is typically distributed using spam email campaigns. Criminals send hundreds of thousands of emails that contain deceptive messages encouraging users to open attached files (Microsoft Office documents). Once opened, these files run commands that inject Astaroth into the system.

Following infiltration, Astaroth injects other malicious apps. At time of research, it was used to proliferate a keylogger designed to steal personal data, however, Astaroth is also used to proliferate other malware.

Astaroth trojan overview

After successful system infiltration, Astaroth performs a chain of actions to inject malware, however, the ultimate result is identical: infiltration of other malware. At time of research, Astaroth targeted users mainly from South America. The keylogger proliferated via Astaroth records browsing activity on the Internet Explorer web browser.

To ensure that people will use this browser, the malware terminates Google Chrome and Mozilla Firefox (the most popular browsers) processes if they are executed. In this way, keylogger attempts to trick users into believing that these browsers are not working properly. With no other browsers available, users are thus encouraged to launch Internet Explorer.

The keylogger targets Brazilian banks and businesses. The malware will only record keystrokes when a specific website is opened, however, if cyber criminals gain access to bank accounts, they will certainly attempt to steal funds. Cyber criminals aim to generate as much revenue as possible.

In some cases, however, these people proliferate viruses with destructive purposes (they attempt to cause data and financial loss). Note that the keylogger developers also target business websites. If criminals gain access to the admin panel of a website, they can cause various issues. E.g., they can remove existing content, add malicious content, delete user accounts, etc.

In addition, these people might inject hijacked websites with scripts used to mine cryptocurrency. In this case, each visitor's computer is used as a cryptomining tool when the website is opened.

Many services provide these functionalities legitimately (e.g., GRIDCASH, CoinImp, Coinhive, etc.), however, criminals misuse cryptomining techniques to generate revenue. Furthermore, many regular users (who are not familiar with cyber security) use an identical password for many accounts.

Thus, after gaining access to one account, criminals can often access others (e.g., emails, social networks, etc.). In any case, the keylogger distributed using Astaroth might cause serious financial/data loss and privacy issues.

Although Astaroth currently distributes keylogging malware, in future, criminals might use this trojan to proliferate other viruses, such as ransomware, cryptominers, and so on. Therefore, Astaroth poses a significant threat to any user.

Trojan examples

There numerous trojan-type viruses distributed using spam email campaigns (e.g., Qakbot, ExileRat, Ave Maria, TrickBot, FormBook, etc.).

The developers of these viruses are different and, thus, the functionality might also differ (some gather information, others inject other viruses, and so on), however, all pose a significant threat to your privacy and computer safety. Therefore, removal of this malware is paramount.

How did Astaroth infiltrate my computer?

As mentioned above, Astaroth is proliferated using spam email campaigns. Criminals send emails with malicious attachments - Microsoft Office documents (Excel, Word, etc.). Once opened, these files ask users to enable macro commands. In doing so,, users grant files permission to execute macros that download and install Astaroth into the system.

This, however, is just the start. After successful infiltration, Astaroth performs many actions to inject additional malware. Astaroth downloads and runs a .lnk file leading to an external URL (.lnk files are typically used as shortcuts to access content stored within the system). Astaroth then downloads a .php file from the URL.

This downloaded .php file contains a style sheet with JavaScript embedded within. The JavaScript code generates a random number to select a CloudFlare URL from which the next payload (another style sheet with JavaScript) is downloaded. The second JavaScript places the malware (a keylogger at time of research).

It also randomly selects a download URL and then copies two Windows OS executables ("certutil" [the copy is renamed to "certix"] and "regsvr32") to the "%TEMP%" folder. Those are later used to finish the malware download. The last step is to check the Program Files folder to determine if the Avast anti-virus suite is installed.

If it is not, the script executes a .dll file and terminates itself. Once all these steps are performed, Astaroth finally executes the downloaded malware (keylogger). Again, bear in mind that Astaroth's behavior (list of actions) might change, depending on whether criminals use this trojan to proliferate other malware.

How to avoid installation of malware?

To prevent these computer infections, be very cautious when browsing the internet. Think twice before opening email attachments. Files that seem irrelevant and those received from suspicious/unrecognizable email addresses should never be opened. These should be deleted without reading.

Furthermore, bear in mind that criminals often send deceptive messages claiming that the recipient will gain something free of charge (e.g., the recipient has won a lottery, received a package, someone has transferred money to the recipient's account, etc.). They hope that the recipient will be tricked into opening the attachment. Do not be fooled by this scam.

Having a reputable anti-virus/anti-spyware suite installed and running at all times is also paramount. These tools commonly detect and eliminate malware before it can harm the system. The main reasons for computer infections are poor knowledge and careless behavior.

The key to safety is caution. If you believe that your computer is already infected, we recommend running a scan with Combo Cleaner Antivirus for Windows to automatically eliminate infiltrated malware.

Another deceptive email promoting Astaroth trojan:

Update March 6, 2020 - Updated version of Astaroth is now capable of taking screenshots, blocking victims from using hotkeys (keyboard shortcuts), downloading and executing files, and restarting a computer. Cyber criminals can use this updated version to take screenshots of victim's computing activities.

For example, make screenshots of opened personal, confidential documents, accounts that contain sensitive information, and capture important data in other ways. Also, they can use it to prevent victims from using keyboard shortcuts. For example, they can prevent them from closing enabled/opened windows by blocking the Alt + F4 keyboard shortcut.

Furthermore, now Astaroth can be used to spread various malware (or other programs) by downloading and executing various files. It means that cyber criminals may infect systems with other malicious software like ransomware, cryptominers, etc. One more thing that now can be done with Astaroth is a system reboot.

For example, it is possible that in order for some changes to take affect it would be necessary to restart a computer and now cyber criminals behind Astaroth could easily do that.

Update March 24, 2020 - To bypass existing detections updated Astaroth version does not execute system tools and use Windows Management Instrumentation Command-line (WMIC). Now it hides malicious payloads by abusing ADS (Alternate Data Streams) and loads them by abusing the  ExtExport.exe, a legitimate process.

At the moment cyber criminals attempt to spread Astaroth through a spam campaign, by sending emails with a website link in them.

The attack chain begins when recipients open that link which leads to an archive (ZIP) file containing a shortcut (LNK) file that runs obfuscated BAT commands to drop a one-line JavaScript file. Also, Astaroth is capable of detecting installed security software, if it detects one, then it attempts to disable it.

Update May 12, 2020 - The Astaroth trojan uses several methods to connect to its C&C (Control and Command) server. One of its recently observed techniques is by connecting to a YouTube channel and retrieving the text in its description. Within it lies an encrypted URL to the C&C server.

However, as Astaroth employs several methods, even if the channel is taken down by YouTube - the malware can fall back to its other tactics in order to establish contact with the C&C server.

Other examples of emails promoting Astaroth trojan:

Sample 1:

Text presented within:

Subject: Vistoria do Corpo de Bombeiros - Comunicado Importante [22/02/2021] - [10:28:42]

AVISO DE VIGÊNCIA DE DOCUMENTOS VENCIDOS
Comunicado importante Nº 68585607
*Ultimo documento enviado VENCIDO*

Protocolo: Q0QXQCWML1X-00248
Serviço: (Segurança)
inicio automático do protocolo : 22/02/2021 - 10:28:42
Status atual: Regularizar pendente ou VENCIDO

Alertamos que o prazo de validade do(s) documento(s) referente ao Termo de Colaboração nº 68585607 celebrado entre Secretaria Municipal dos bombeiros e CENTRO SOCIAL NOSSA SENHORA, para funcionamento da CEI: CR.P.CONV - CNPJ cadastrado para este e-mail ( - ) que devem ser regularizados com urgência está(ão) na situação de vencido. Encaminhe a respectiva documentação à DIR EDUC - DIRETORIA REGIONAL DOS BOMBEIROS
A não regularização dos itens informados pode implicar na suspensão de seu CNPJ em 30 DIAS bem como multa previstos no Art 37 da Lei 10.335 de 19 de Julho de 1988.

#    Documento    Vencimento
05    - AVCB – Auto de Vistoria do Corpo de Bombeiros    12/2020
 

Providencie a sua regularização, com vistas à continuidade da prestação do serviço.

Atenciosamente,
SMB – Secretaria Municipal dos Bombeiros

Sample 2:

Text presented within:

Subject: Identificamos divérgencias (Imposto de Renda pessoa Fisica)- Notificaçâo: -.

 

Receita Federal

AVISO DE IRREGULARIDADE

GOVERNO FEDERAL BRASIL
PAIS RICO E PAIS SEM POBREZA

Caro contribuinte,

A Receita Federal Faz anualmente uma análise detalhada da entrega do Imposto de Renda e encontrou problemas relacionados ao seu CPF cadastrado para este e-mail que devem ser regularizados com urgência.

Em anexo, segue um demostrativo de pendências passíveis de regularização. A não regularização dos itens informados pode implicar na suspensão de seu CPF, bem como multa previstas no Art 37 da Lei 10.522 de 19 de Julho de 2002.

Visualize o extrato do IRPF abaixo para maiores esclarecimentos.

Formulário Pessoa Física (18KB)

88747878-01 - RECEITA FEDERAL - GOVERNO FEDERAL DO BRASIL

Sample 3:

Text presented within:

Subject: SPAM: Documento Pendente de Assinatura. Protocolo: 650202271

DocuSign
Seu documento digital está pronto para análise e assinatura digital.
REVISAR DOCUMENTO DIGITAL
Documento:
DocuSing_eSignature_Digital Nº: salud@asuss.gob.bo -4273-728298

Para analisar e assinar seu documento, basta clicar em "REVISAR DOCUMENTO DIGITAL".

Sample 4:

Text presented within:

Subject: Consumidor Denuncia. Protocolo: 214208470

Notificação do Procon

Prezado(a) ouvidoria@hcor.com.br ,

Informamos que o Procon recebeu uma denúncia em relação a uma possível violação dos direitos do consumidor em sua empresa/estabelecimento.

Solicitamos que compareça ao Procon mais próximo no prazo de 10 dias, afim de esclarecer os fatos e providenciar uma solução adequada.

Para verificar os autos da notificação, acesse: Verificar Autos

Agradecemos sua atenção e colaboração.

Atenciosamente,

Equipe do Procon

Sample 5:

Text presented within:

DocuSign
Seu documento digital está pronto para análise e assinatura digital.

Olá, dsvc@vychodnicechy.info

Clique no botão abaixo para visualizar e assinar o seu documento digital com segurança:

REVISAR DOCUMENTO DIGITAL
Documento: DocuSign Nº 646151324374262491031
Data: 11/06/2025
Horário: 22:39:02
Este documento é confidencial. Por favor, não compartilhe este documento com terceiros.

Mensagem automática - não responda este e-mail.

Update October 14, 2025 - Recently, a new campaign delivering Astaroth has been discovered. In this campaign, the malware exploits GitHub to store its setup information. The attack begins with a deceptive email containing a link to a compressed Windows shortcut (.lnk) file. Opening this file infects a computer with Astaroth.

The malware monitors visits to banking and cryptocurrency websites and captures login credentials using a keylogger. The stolen information is sent to the attacker through Ngrok. If the malware's control servers are unavailable, it can update its settings by hiding data inside images on GitHub. It is important to note that the malicious repositories have already been removed.

Update January 13, 2026 - It has been found that Astaroth now spreads through WhatsApp, mainly targeting users in Brazil. It arrives as a malicious ZIP file sent via WhatsApp messages. When executed, the malware infects the system and automatically sends itself to the victim's contacts, helping it spread further. Its main goal is to steal banking and financial information using trusted messaging platforms.

How to remove malware manually?

Most trojan infections can be removed by running a full system scan with Combo Cleaner. The full manual procedure below is for cases where automatic removal failed, where you want to verify a scan caught everything, or where the threat has multiple persistence points.

Tools you'll need

Combo Cleaner Antivirus 7-days free trial

Recommended primary scanner. VB100 certified. The 7-day free trial is available.

Microsoft Defender Offline Free · built-in

Built into Windows. Boots to a clean environment to catch rootkits.

Process Explorer Free

From Microsoft Sysinternals. Better than Task Manager - shows full paths and signatures.

Autoruns Free

From Microsoft Sysinternals. Lists every place malware can persist on your system.

Microsoft Safety Scanner (MSERT) Free

Official Microsoft on-demand scanner. Always-current signatures - expires every 10 days.

Phase 1~ 5 min

Contain - limit the damage

---

1

Disconnect from the network

30 secNo tool needed

Unplug your Ethernet cable and turn off Wi-Fi. If you're on a laptop, the airplane-mode key works fastest.

Why this matters

Many trojans exfiltrate data - saved browser passwords, banking sessions, screenshots - and accept remote commands. Cutting the network stops both immediately. Keep it disconnected until Phase 4.

2

Boot into Safe Mode with Networking

3 min

Safe Mode loads a minimal set of drivers and stops most malware from auto-running. "With Networking" lets you download tools - re-enable Wi-Fi only after you've booted in.

Windows 11

Open Settings → System → Recovery. Click Restart now next to Advanced startup.

Your computer will restart into the "Choose an option" menu. Click Troubleshoot → Advanced options → Startup Settings → Restart. After the second reboot, press 5 or F5.

Windows 10

Click the Windows logo, hold Shift, click the Power icon and choose Restart. In the Choose an option screen, click Troubleshoot → Advanced options → Startup Settings → Restart. Press F5.

Windows 8

Go to the Start Screen, type Advanced, select Settings → Advanced startup options → Restart now → Troubleshoot → Advanced options → Startup settings → Restart → F5.

Note: Windows 8 reached end-of-life in January 2023 - running on it puts you at much higher risk of reinfection.

Windows 7

Click Start → Shut Down → Restart → OK. As the system boots, press F8 repeatedly until the Windows Advanced Options menu appears, then choose Safe Mode with Networking.

Note: Windows 7 reached end-of-life in January 2020 - running on it puts you at much higher risk of reinfection.

Phase 2~ 15 min

Identify - find what's hiding

---

3

Inspect running processes with Process Explorer

Tool: Process Explorer5 min

Download Process Explorer from Microsoft Sysinternals. Run it as Administrator. Click Options → Verify Image Signatures and View → Lower Pane View → DLLs.

Sort by "Verified Signer." Anything unsigned running from %AppData%, %LocalAppData%, %Temp%, or %ProgramData% is suspicious. Right-click → Properties to see the full image path. Right-click → "Search Online" to look up unfamiliar process names.

Why not just Task Manager

Task Manager hides full file paths, doesn't show digital signatures, and groups processes in ways that make malware easy to miss. Process Explorer is the same tool Microsoft engineers use.

4

Map every persistence point with Autoruns

Tool: Autoruns 14.x10 min

Download Autoruns. Right-click Autoruns.exe and choose Run as administrator - without elevation, Autoruns can't inspect protected registry hives.

In the menu, open Options → Hide Microsoft Entries and Options → Hide Empty Locations, then click Refresh.

Modern trojans don't just live in startup. Walk through these tabs and look for unsigned or unfamiliar entries:

• Logon - classic Run/RunOnce keys
• Scheduled Tasks - frequent hiding spot, especially tasks with PowerShell, MSHTA, or rundll32 actions
• Services - unsigned services in non-Microsoft folders
• WMI - Event Subscriptions are a stealthy persistence mechanism (MITRE T1546.003)
• Image Hijacks - Image File Execution Options "Debugger" abuse
• AppInit - DLLs loaded into every GUI process
• Browser plug-ins - unsigned add-ons across all installed browsers

Pro tip

Right-click any suspicious entry → "Jump to Image" to see the actual file. Right-click → "Search Online" opens VirusTotal for the file hash. Don't delete yet - just write down the file paths and entry names. We'll remove them after the scans.

5

Check the hosts file and DNS settings

3 minBuilt into Windows

Trojans often redirect bank, antivirus, and update domains to attacker-controlled servers by editing the hosts file or DNS settings.

Hosts file: Open Notepad as Administrator and open C:\Windows\System32\drivers\etc\hosts. Legitimate entries are commented with #. Any uncommented IP-to-domain mapping is suspicious - especially redirects for microsoft.com, windowsupdate, or your bank.

DNS settings: Open Command Prompt as Administrator and run ipconfig /all. Confirm your DNS servers point to your ISP, your router, or a known public resolver (Cloudflare 1.1.1.1, Google 8.8.8.8). Then open Settings → Network & internet → [your adapter] → DNS server assignment and verify both DNS and DNS over HTTPS (DoH) settings haven't been hijacked.

Why this matters

A clean PC with hijacked DNS is still a compromised PC. You'll think you're at chase.com and you'll be at the attacker's clone.

Phase 3~ 60-90 min

Remove - three scans, one cleanup

---

No single antivirus catches everything. The order below is intentional: offline scan first (catches rootkits before Windows fully loads), then on-demand scanners on the running system, then manual cleanup of anything they missed.

6

Run Microsoft Defender Offline

Tool: Built into Windows15 min

Reboot to normal Windows. Open Windows Security → Virus & threat protection → Scan options. Select Microsoft Defender Antivirus (offline scan) and click Scan now. Your computer will restart into a stripped-down environment and scan before the full operating system loads.

Why this comes first

Rootkits and bootkits hide from any scanner running on the same Windows session that's already infected. A pre-boot offline scan sees the disk before the malware can hide itself.

Recommended antivirus

Combo Cleaner

VB100 certified. Includes anti-trojan, registry/persistence scanning, anti-spyware in one pass. The 7-day free trial is available.

Download Combo Cleaner

7

Run Combo Cleaner full system scan

Tool: Combo Cleaner20-40 min

Install Combo Cleaner and run a full system scan (not the quick scan). Let it complete fully, review the detected threats, and apply the recommended actions. Combo Cleaner will quarantine known trojans and registry persistence.

8

Run Microsoft Safety Scanner as a second-opinion scan

Tool: Microsoft Safety Scanner15 min

Download Microsoft Safety Scanner (MSERT.exe), Microsoft's free on-demand tool. The binary expires every 10 days, which means every download has the latest signatures. Run a full scan after Combo Cleaner to catch anything one engine alone might miss.

Why a second scan

Different scanning engines catch different threats. Running an additional Microsoft scan after Combo Cleaner is the single most underused verification step in malware removal.

9

Manually remove anything still listed in Autoruns

Tool: Autoruns10 min

Reopen Autoruns. Anything you flagged in Step 4 that's still present hasn't been caught by the automated scans. For each remaining suspicious entry: right-click → Delete in Autoruns (this removes the persistence registration), then navigate to the file path and delete the actual file. Empty the Recycle Bin.

Important

Some malware files reappear after deletion because something else on the system recreates them. If you delete a file and it returns within minutes, you have a remaining persistence point that Autoruns didn't show - usually a service or scheduled task running under SYSTEM. Re-run the scans from Steps 6-8 or proceed to a clean install (see end of guide).

Phase 4~ 15 min

Recover - restore browsers and security

---

10

Reset browsers and clear notification permissions

5 min

Trojans and adware frequently hijack browsers - change the default search engine, install rogue extensions, or grant themselves notification permissions to keep displaying scam pop-ups even after the malware is gone.

• Chrome: visit chrome://settings/reset and click "Restore settings to their original defaults." Then visit chrome://settings/content/notifications and remove any unfamiliar sites.
• Edge: visit edge://settings/reset. Then check edge://settings/content/notifications.
• Firefox: open about:support and click Refresh Firefox (Firefox uses "Refresh," not "Reset"). Then check Settings → Privacy & Security → Permissions → Notifications.

Review installed extensions in each browser and remove anything you don't recognize, especially extensions you didn't install yourself.

11

Re-enable Defender, Tamper Protection, and update everything

10 min

Many trojans disable security software. Open Windows Security → Virus & threat protection → Manage settings and confirm Real-time protection, Cloud-delivered protection, and Tamper Protection are all turned on. Tamper Protection prevents malware from disabling Defender silently.

Then run Windows Update (Settings → Windows Update → Check for updates) and update your browsers and applications. The infection vector that let the trojan in originally usually involves outdated software.

Phase 5~ 15 min + 7 days

Verify & secure

---

12

Change passwords from a clean device

20 min⚠ Critical

If the trojan was an info-stealer (Lumma, RedLine, Vidar, and similar are extremely common), assume every password saved in your browser is compromised. Change them from a different, known-clean device - your phone is fine if it's not infected.

Recommended order:

1. Primary email first - it's the recovery hub for everything else
2. Banking and financial accounts
3. Password manager master password (if you use one)
4. Social media, shopping, and remaining accounts

Where available, enable phishing-resistant multi-factor authentication (passkeys / FIDO2 hardware keys / authenticator apps) - SMS-based MFA is bypassable by sophisticated attackers.

13

Verify the clean and monitor for 7 days

5 min + 1 week monitoring

Reconnect to the network and run one final full scan with Combo Cleaner. Open Task Manager (Ctrl + Shift + Esc) and switch to the Startup apps tab - confirm nothing suspicious has reappeared.

Over the next 7 days, watch for symptom recurrence: unexpected high CPU usage, unknown processes returning, browser redirects, or pop-ups. If anything returns, you missed a persistence point and the procedure needs to be repeated - or you may have a deeper compromise that requires a clean install.

When to clean install Windows instead

Manual removal isn't always the right answer. Reinstalling Windows from scratch is the only way to be 100% certain when:

• The malware reappears after every removal attempt
• A bootkit or UEFI rootkit was detected (this class of threat sits below the operating system and survives a normal Windows reinstall)
• A confirmed credential-theft trojan ran with administrator privileges (Lumma, RedLine, Vidar) - the system likely has multiple unknown payloads
• The PC is used for online banking, business email, or anything where partial doubt isn't acceptable

A clean install is a 30-60 minute process: Windows 11 reinstall via Settings → System → Recovery → Reset this PC → Remove everything → Cloud download. Back up documents to external storage first, scan the backup with Combo Cleaner before restoring it, and reinstall applications fresh - never restore them from a backup of the infected system.

Important: Manual removal requires advanced computer skills. If you're not confident identifying system files from malicious files, run an automated scan with Combo Cleaner and Windows Defender and stop there - that path catches the vast majority of consumer trojans without the risk of breaking Windows by deleting the wrong file.

Frequently Asked Questions (FAQ)

My computer is infected with Astaroth malware, should I format my storage device to get rid of it?

Malware removal rarely requires formatting.

What are the biggest issues that Astaroth malware can cause?

The dangers posed by an infection depend on the malware's capabilities and the cyber criminals' goals. Astaroth is a trojan that can cause chain infections (i.e., download/install additional malware) and possesses data-stealing capabilities. Generally, the presence of such software on devices can result in multiple system infections, severe privacy issues, financial losses, and even identity theft.

What is the purpose of Astaroth malware?

Malware is mainly used to generate revenue. However, cyber criminals can also use malicious programs to amuse themselves, carry out personal vendettas, disrupt processes (e.g., sites, services, companies, etc.), engage in hacktivism, and launch politically/geopolitically motivated attacks.

How did Astaroth malware infiltrate my computer?

Malware is most commonly distributed via spam emails/messages, drive-by downloads, online scams, malvertising, untrustworthy download sources (e.g., freeware and third-party websites, P2P sharing networks, etc.), pirated content, illegal software activation ("cracking") tools, and fake updates. Some malicious programs can self-proliferate through local networks and removable storage devices.

Will Combo Cleaner protect me from malware?

Yes, Combo Cleaner is capable of detecting and eliminating nearly all known malware infections. Note that performing a full system scan is paramount since high-end malicious software tends to hide deep within systems.