C0055 Quad7 Activity

Quad7 Activity, also known as CovertNetwork-1658 or the 7777 Botnet, is a network of compromised small office/home office (SOHO) routers. The botnet was initially composed primarily of TP-Link routers and was named Quad7 due to compromised devices exposing TCP port 7777 with the distinctive banner xlogin. Later activity showed a significant increase in compromised Asus routers and the addition of new ports and banners, including TCP port 63256 displaying alogin. Quad7 infrastructure functions as a collection of egress IPs that various China-affiliated threat actors have used to conduct password-spraying and brute-force operations. Microsoft has reported that Storm-0940 leveraged credentials obtained through Quad7 Activity to target organizations in North America and Europe, including government agencies, non-governmental organizations, think tanks, law firms, energy firms, IT providers, and defense industrial base entities.