New Osiris Ransomware Emerges as New Strain Using POORTRY Driver in BYOVD Attack

Cybersecurity researchers have disclosed details of a new ransomware family called Osiris that targeted a major food service franchisee operator in Southeast Asia in November 2025. The attack leveraged a malicious driver called POORTRY as part of a known technique referred to as bring your own vulnerable driver (BYOVD) to disarm security software, the Symantec and Carbon Black Threat Hunter