Cato CTRL Threat Research: SilverFox Evolves: Abuse of New Drivers and Trusted Software Hijacking Enable Remote Access with ValleyRAT in Japan
SilverFox is expanding its toolkit. In this campaign, the group combines new vulnerable-driver abuse, newly observed abuse of legitimate applications for DLL sideloading, defense evasion, and layered recovery mechanisms to keep ValleyRAT running. We investigated an active campaign targeting a Japanese organization in the industrial manufacturing sector. The attack begins with an invoice-themed phishing lure and uses attacker-controlled content hosted through legitimate QQ and Tencent Cloud services.