Available in both Python and C variants, CastleRAT's core functionality consists of collecting system information, downloading and executing additional payloads, and executing commands via CMD and PowerShell," Recorded Future Insikt Group said.
The campaign leverages "carefully crafted emails to deliver malicious URLs linked to convincing phishing pages," Fortinet FortiGuard Labs researcher Cara Lin said. "These pages are designed to entice recipients into downloading JavaScript files that act as droppers for UpCrypter." Attacks propagating the malware have been primarily targeting manufacturing, technology, healthcare, construction, and retail/hospitality sectors across the world since the start of August 2025. The vast majority of the infections have been observed in Austria, Belarus, Canada, Egypt, India, and Pakistan, among others.
