When the National Security Agency (NSA) and the Federal Bureau of Investigations (FBI) get together to issue a joint warning, you may wish to listen up.

The NSA and FBI recently alerted the defense industry through a Cybersecurity Advisory of the risk of malware attacks targeted at the defense and aerospace sectors by Russia’s General Staff Main Intelligence Directorate’s 85th Main Special Service Center, also known as Fancy Bear,  APT28 or GRU. The attacks are specific to Linux systems.

According to the Advisory, “[T]he malware represents a threat because Linux systems are used pervasively throughout National Security Systems, department of Defense and the Defense Industrial Base” so “stakeholders should take action as appropriate.”

Following the Advisory, security experts are suggesting that if an organization uses Linux systems, assessment of security tools to detect and prevent malware is a top priority.