A cunning predator: How Silver Fox preys on Japanese firms this tax season

Silver Fox is conducting a targeted spearphishing campaign against Japanese companies timed to the annual tax and HR season, sending realistic HR- and tax-themed emails that impersonate internal staff and prompt recipients to open malicious attachments or links; successful infections drop ValleyRAT, a remote access trojan used to harvest data, maintain persistence, and facilitate further intrusion. The activity is active, tailored with prior reconnaissance, affects multiple sectors, and includes published IoCs on the vendor's GitHub.