The FBI warns that older Wi-Fi routers from the late 2000s and early 2010s are vulnerable to cyber attacks. These devices can be easily hijacked by hackers who exploit known security flaws in their software. The affected models include those from Linksys, such as the E1200, E2500, and WRT320N.
When a router goes out of date, it no longer receives software updates or security patches, making it an attractive target for cybercriminals. Hackers can use remote administration software to upload malware onto these devices, gaining access to them and turning them into proxy servers that others can rent or use.
The problem is that traditional antivirus tools don’t scan networking hardware, so the malicious files live undetected within the router’s operating system. This makes it difficult to detect when a home router has been compromised. If you have an outdated router, consider replacing it with a newer model that gets software updates and security patches.
Source: https://www.slashgear.com/2104404/wifi-routers-unsafe-fbi-warning