WhatsApp Under Siege: The New Wave of Self-Propagating Malware
Messaging apps like WhatsApp have become part of our daily lives, from family chats to workplace discussions. But cybercriminals are now using these same trusted platforms to spread dangerous malware that can replicate itself and infect others automatically. Recent security findings show that a new set of malware campaigns, mainly targeting users in Brazil, are spreading through WhatsApp and even hijacking the app to infect more victims.
What’s Happening
Several major cybersecurity firms, including Trend Micro, Kaspersky, and The Hacker News, have reported active malware strains such as Water Saci, SORVEPOTEL, and Maverick spreading through WhatsApp. These threats combine self-replication, banking data theft, and account hijacking in a single campaign.
- Trend Micro discovered that the Water Saci or SORVEPOTEL campaign spreads through WhatsApp messages containing ZIP files. Once opened, these files execute malicious PowerShell and .NET scripts that hijack the victim’s WhatsApp Web session and send the same infected file to all contacts.
- Kaspersky’s Securelist identified the Maverick banking trojan, also distributed via WhatsApp ZIP attachments. The malware uses advanced techniques like fileless execution, keylogging, and session hijacking to steal sensitive data, especially from Brazilian banking and financial websites.
- The Record and The Hacker News confirmed that these campaigns are targeting government institutions, public networks, and business accounts in Brazil through WhatsApp distribution chains.
Why It Matters
WhatsApp is trusted, fast, and personal. When a malicious file comes from a known contact, people rarely doubt it. This mix of social engineering and automation makes the attack extremely dangerous. Even if your organization isn’t in Brazil, the method itself can easily be reused anywhere.
For companies that allow employees to use personal messaging apps on office systems or within Bring Your Own Device (BYOD) setups, the risks multiply. Once a single system is compromised, the malware can spread quickly through shared networks or social groups.
How the Attack Works
- Delivery: The victim receives a WhatsApp message from a known contact containing a ZIP file with a name like “ORÇAMENTO_114418.zip”.
- Execution: The ZIP file includes a hidden Windows shortcut (.LNK) that runs PowerShell commands to download more malware components.
- Propagation: The malware checks for an active WhatsApp Web session and, if found, sends the same malicious file to all contacts automatically using browser automation tools like Selenium and JavaScript APIs.
- Data Theft: Some variants, like Maverick, target online banking and cryptocurrency websites, capturing credentials and stealing financial data.
- Evasion: These threats check system language, timezone, and date format to confirm the target region, and they use heavy code obfuscation to avoid antivirus detection.
Why Companies Everywhere Should Care
Although these attacks focus on Brazil right now, the techniques are easy to adapt globally. In workplaces where employees use WhatsApp on company laptops or share files through WhatsApp Web, the risk of a single infection spreading across departments is very real.
As remote work and BYOD environments expand, the boundary between personal and professional devices keeps blurring. This gives attackers an easy way into corporate systems through personal messaging platforms.
How to Protect Your Organization
- Limit WhatsApp on corporate systems: Disable automatic file downloads and restrict WhatsApp Web sessions on company networks.
- Enforce script restrictions: Block or monitor the execution of PowerShell, batch (.BAT), and shortcut (.LNK) files through application control policies.
- Enhance EDR visibility: Monitor unusual browser automation activity or multiple file transfers from WhatsApp sessions.
- Train your teams: Conduct regular awareness programs showing real-world examples of how malware spreads through messaging apps. Employees should know to verify even files from trusted contacts.
- Update incident response playbooks: Include messaging app-based infection scenarios and ensure logs capture activity within WhatsApp Web sessions.
Terra System Labs: Helping You Stay Secure
At Terra System Labs Pvt. Ltd., our experts specialize in identifying, simulating, and preventing such attacks through services like:
- Vulnerability Assessment and Penetration Testing (VAPT)
- Secure Code Reviews
- Phishing Simulation and Cybersecurity Awareness Training
- Red Team and Incident Response Exercises
- Cloud and BYOD Security Consulting
We can simulate these WhatsApp-based propagation attacks during your next red-team engagement or design a phishing simulation campaign that helps employees recognize such social engineering tactics before it’s too late.
Conclusion
The recent wave of self-spreading WhatsApp malware reminds us that attackers follow where people communicate most. From personal chats to workplace groups, every message can become an infection path if users let their guard down. Organizations must now treat instant messaging platforms as a part of their broader attack surface, not as private, isolated tools.
By combining technical controls, clear policies, and human awareness, companies can prevent a small mistake from becoming a major security breach. Terra System Labs is ready to help your team assess and strengthen defences against these evolving threats.
Key Takeaways
- WhatsApp and similar apps are now prime targets for malware campaigns.
- Self-propagating malware can spread through trusted contacts and groups.
- The attacks may start in one region but can scale globally.
- Security awareness and endpoint protection are essential to stop such threats.
Contact Terra System Labs today to learn how we can help your organization stay one step ahead of emerging digital threats.
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