The FBI has issued a public service announcement warning that Russian cyber espionage actors linked to the FSB, specifically the Static Tundra group and the FSB Center 16 unit, are exploiting a seven-year-old vulnerability in Cisco networking devices. These unpatched, end-of-life devices, which are widely used across critical infrastructure sectors including telecommunications, manufacturing, power grids, and water treatment facilities, are being targeted globally to steal configuration data, implant malware such as SYNful Knock, and hijack network traffic for espionage purposes. The vulnerability, first addressed by Cisco in 2018, continues to be exploited in ongoing cyber campaigns aimed at compromising sensitive systems. The FBI's alert highlights the persistent threat posed by state-sponsored Russian hackers amid heightened diplomatic tensions with the Kremlin.