A new phishing campaign distributes Horabot malware. It targets Windows users in Latin American countries. These include Mexico, Guatemala, Colombia, Peru, Chile, and Argentina. Crafted emails impersonate invoices or financial documents. They trick victims into opening malicious attachments. The malware can steal email credentials. It also harvests contact lists. Additionally, it installs banking trojans. Fortinet FortiGuard Labs observed this activity in April 2025. The campaign primarily singles out Spanish-speaking users.
The attacks send phishing messages from victims’ mailboxes. They use Outlook COM automation for this purpose.
This effectively propagates the malware laterally. It spreads within corporate or personal networks. Threat actors execute various VBScript, AutoIt, and PowerShell scripts. These conduct system reconnaissance and steal credentials. They also drop additional malicious payloads. Horabot was first documented by Cisco Talos in June 2023. It has targeted Latin America since November 2020. Attacks are linked to a Brazilian threat actor.
The latest attacks start with an invoice-themed phishing email. Users are enticed to open a ZIP archive. This archive actually contains a malicious HTML file. The HTML file has Base64-encoded HTML data. This data contacts a remote server. It then downloads the next-stage payload. This payload is another ZIP archive. It contains an HTML Application (HTA) file. The HTA file loads a script from a remote server.
This script injects an external Visual Basic Script. The VBScript checks for Avast or virtual environments.
If no defenses are found, the VBScript collects system information. It exfiltrates this data to a remote server. It then retrieves additional payloads. These include an AutoIt script. This script unleashes the banking trojan using a malicious DLL. A PowerShell script also runs. It spreads phishing emails after scanning Outlook contacts. Horabot steals browser data from many web browsers. It also monitors victim behavior. Fake pop-up windows capture user login credentials. FortiGuard Labs urges strong email filtering and user education.
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