Hackers working on behalf of the Chinese government are using a botnet of thousands of routers, cameras, and other Internet-connected devices to perform highly evasive password spray attacks against users of Microsoft’s Azure cloud service, the company warned Thursday.
The malicious network, made up almost entirely of TP-Link routers, was first documented in October 2023 by a researcher who named it Botnet-7777. The geographically dispersed collection of more than 16,000 compromised devices at its peak got its name because it exposes its malicious malware on port 7777.
Account compromise at scale
In July and again in August of this year, security researchers from Serbia and Team Cymru reported the botnet was still operational. All three reports said that Botnet-7777 was being used to skillfully perform password spraying, a form of attack that sends large numbers of login attempts from many different IP addresses. Because each individual device limits the login attempts, the carefully coordinated account-takeover campaign is hard to detect by the targeted service.