The United States has warned of possible threats to satellite communications (SATCOM) networks, with Australia's biggest telecommunications firms already on heightened alert.
"Telstra actively monitors the global threat environment and is aware of the advice published by CISA (US Cybersecurity and Infrastructure Security Agency)," a Telstra spokesman told AAP on Friday.
Advice overnight from the CISA and the Federal Bureau of Investigation (FBI) warned of possible threats to US and international SATCOM networks, and spillover risk to companies making use of satellite data services.
"We recognise the heightened threat environment and continue to evolve and strengthen our security to continue to protect our network and customers," Telstra said.
Andrew Sheridan, vice president at Optus, told AAP the telco was monitoring the domestic and international cyber situation closely, including running exercises that assess potential impacts across supply chains.
"Using threat intelligence, analysis and expert recommendations, we aim to employ global best practice in cyber security to protect our network and our customers," he said.
Telco firms are among the sectors classed as Australian critical infrastructure and work closely with government and global intelligence experts as well as running their own in-house security operations centres.
The Australian Cyber Security Centre has warned the risk of cyber attacks has increased in the wake of the Ukraine conflict.
"Successful intrusions into SATCOM networks could create risk in SATCOM network providers' customer environments," the latest US alert warns.
But there are no specific cyber threats to Australian critical infrastructure at present.
Elsewhere, German energy company Enercon said it lost remote access to more than 5800 wind turbines in central Europe after a partial outage in a satellite internet service provided by US firm Viasat.
"The communication services failed almost simultaneously with the start of the Russian invasion of Ukraine," Enercon said last month.
Viasat said at the time the suspected cyber attack affected internet services for fixed broadband customers in Ukraine and other European countries on the KA-SAT network.
Some older modems were wiped by a malicious update and were rendered permanently inoperable in the attack that affected 30,000 satellite terminals, tech media reported.
Russia has been a long-standing host of sophisticated cyber actors.
US agencies earlier this week also released tips to defend against Russian state-sponsored cyber actors who have been exploiting a bug in Windows Print Spooler software that temporarily stores print jobs in a computer's memory.
The critical vulnerability known as "PrintNightmare" can allow cyber criminals to access cloud and email accounts and potentially steal documents.
