A new malware campaign is turning WhatsApp Web into a weapon. Security researchers say a banking Trojan linked to Astaroth is now spreading automatically through chat messages, making the attack harder to stop once it starts.
The campaign is known as Boto Cor-de-Rosa. It shows how cybercriminals keep evolving, especially when they can abuse tools people trust every day. This attack focuses on Windows users and uses WhatsApp Web as both the delivery system and the engine that spreads the infection further.
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The attack starts with a simple message. A contact sends what looks like a routine ZIP file through WhatsApp. The file name appears random and harmless, which lowers suspicion. Once opened, the ZIP contains a Visual Basic script disguised as a normal document. If the user runs it, the script quietly pulls in two more pieces of malware. Then the script downloads the Astaroth banking malware written in Delphi. It also installs a Python-based module designed to control WhatsApp Web. Both components run in the background without obvious warning signs. From there, the infection becomes self-sustaining.
What makes this campaign especially dangerous is how it propagates. The Python module scans the victim’s WhatsApp contacts and sends the malicious ZIP file to every conversation automatically. Researchers at Acronis found that the malware adapts its messages based on the time of day. It sends friendly greetings, making the message feel normal and familiar. The text reads, “Here is the requested file. If you have any questions, I’m available!” Because the message appears to come from someone you know, many people open it without hesitation.
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This malware is carefully designed to monitor its own performance in real time. The propagation tool tracks how many messages are successfully delivered, how many fail to send, and the overall sending speed measured per minute. After every 50 messages, it generates progress updates that show how many contacts have been reached. This feedback allows attackers to measure success quickly and make adjustments if something stops working.
The initial script is heavily obfuscated to avoid detection by antivirus tools. Once it runs, it launches PowerShell commands that download more malware from compromised websites. One known domain used in this campaign is coffe-estilo.com. The malware installs itself inside a folder that mimics a Microsoft Edge cache directory. Inside are executable files and libraries that make up the full Astaroth banking payload. From there, the malware can steal credentials, monitor activity and potentially access financial accounts.
WhatsApp Web is popular because it mirrors your phone conversations on a computer. That convenience makes it easy to send messages, share files and type faster, but it also introduces risk. When you use WhatsApp Web, you link your phone to a browser by scanning a QR code at web.whatsapp.com. Once connected, that browser session becomes a trusted extension of your account. Your chats appear on the screen, messages you send come from your real number and incoming messages sync across both devices.
That setup is exactly what attackers take advantage of. If malware gains access to a computer with WhatsApp Web logged in, it can act as the user. It can read messages, access contact lists and send files or links that look completely legitimate. The messages do not raise alarms because they are coming from a real account, not a fake one.
This is what turns WhatsApp Web into an effective delivery system for malware. Instead of breaking into WhatsApp itself, attackers simply abuse an open browser session to spread malicious files automatically. Many users do not realize the danger because WhatsApp Web feels harmless. It is often left signed in on work computers, shared devices or systems without strong security. In those situations, malware does not need advanced tricks. It only needs access to an already trusted session. That combination of convenience and trust is why WhatsApp Web has become such an attractive target.
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Attacks like this WhatsApp Web malware are designed to spread fast through trusted conversations. A few smart habits can dramatically lower your risk.
Messaging apps feel casual, which is exactly why attackers use them. Never open ZIP files sent through chat unless you confirm with the sender first. Watch for file names made of random numbers or unfamiliar names. Treat messages that create urgency or feel overly familiar as a warning sign. If a file arrives out of nowhere, pause before clicking.
This campaign abuses WhatsApp Web to spread automatically once a device is infected. Check active WhatsApp Web sessions and log out of any you do not recognize. Avoid leaving WhatsApp Web signed in on shared or public computers. Enable two-factor authentication (2FA) inside WhatsApp settings. Cutting off Web access helps limit how far malware can travel.
This type of malware takes advantage of systems that fall behind on updates. Install Windows updates as soon as they are available. Also, keep your web browser fully updated. Staying current closes many of the doors attackers try to slip through. In addition, use strong antivirus software that watches for script abuse and PowerShell activity in real time.
The best way to safeguard yourself from malicious links that install malware, potentially accessing your private information, is to have strong antivirus software installed on all your devices. This protection can also alert you to phishing emails and ransomware scams, keeping your personal information and digital assets safe.
Get my picks for the best 2026 antivirus protection winners for your Windows, Mac, Android & iOS devices at Cyberguy.com.
Banking malware often pairs with identity theft and financial fraud. One way to reduce the fallout is by shrinking your digital footprint. A data removal service can help remove your personal information from data broker sites that attackers often search. With less information available, criminals have fewer details to exploit if malware reaches your device.
While no service can guarantee the complete removal of your data from the internet, a data removal service is really a smart choice. They aren’t cheap, and neither is your privacy. These services do all the work for you by actively monitoring and systematically erasing your personal information from hundreds of websites. It’s what gives me peace of mind and has proven to be the most effective way to erase your personal data from the internet. By limiting the information available, you reduce the risk of scammers cross-referencing data from breaches with information they might find on the dark web, making it harder for them to target you.
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Even with strong security habits, financial monitoring adds another layer of protection. An identity theft protection service can watch for suspicious activity tied to your credit and personal data. Identity theft companies can monitor personal information like your Social Security number (SSN), phone number, and email address, and alert you if it is being sold on the dark web or being used to open an account. They can also assist you in freezing your bank and credit card accounts to prevent further unauthorized use by criminals.
You should also turn on alerts for bank and credit card transactions so you are notified quickly if something looks wrong. The less exposed your data is, the fewer opportunities attackers have to cause damage.
See my tips and best picks on how to protect yourself from identity theft at Cyberguy.com.
Most malware infections happen because people act too quickly. If a message feels off, trust that instinct. Familiar names and friendly language can lower your guard, but they should never replace caution. Take a moment to verify the message or file before opening anything. Attackers rely on trust and urgency to succeed. Slowing down takes away their advantage.
This WhatsApp Web malware campaign is a reminder that cyberattacks no longer rely on obvious red flags. Instead, they blend into everyday conversations and use familiar tools to spread quietly and quickly. What makes this threat especially concerning is how little effort it takes for it to move from one device to dozens of others. A single click can turn a trusted chat into a delivery system for banking malware and identity theft. The good news is that small changes make a big difference. Paying attention to attachments, locking down WhatsApp Web access, keeping devices updated and slowing down before clicking can stop these attacks cold. As messaging platforms continue to play a bigger role in daily life, staying alert is no longer optional. Awareness and simple habits remain some of the strongest defenses you have.
Do you think messaging apps are doing enough to protect users from malware that spreads through trusted conversations? Let us know by writing to us at Cyberguy.com.
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