England players and staff will be advised not to use public or hotel Wi-Fi at next summer's World Cup in Russia over hacking fears.
The Football Association is concerned that sensitive information such as injury, squad selection and tactical details could be exposed.
The advice is understood to have been put into action by the FA already, but worries over data theft have increased following last month's Fancy Bears hack regarding the use of banned medicines in football.
The hacking group claimed the information showed that 160 players had failed drugs tests in 2015, with the number rising to 200 the following year.
The FA has written to Fifa with its concerns about IT security, and is thought to be particularly concerned about the leaking of its own correspondence with the governing body.
An email from FA head of integrity Jenni Kennedy, which revealed details regarding four anti-doping cases in May 2017, was released in the August hack.
In response to the FA's letter, a Fifa spokesman said: "Fifa has informed the FA that [it] remains committed to preventing security attacks in general and that, with respect to the Fancy Bears attack in particular, it is presently investigating the incident to ascertain whether Fifa's infrastructure was compromised.
"Such investigation is still ongoing. For the purposes of computer security in general, Fifa is itself relying on expert advice from third parties.
"It is for this reason that Fifa cannot and does not provide any computer security advice to third parties."
England, who are top of their World Cup qualifying group, will confirm their place in Russia with victory against Slovenia at Wembley in their next qualifier on 5 October.
FA officials are understood to be increasingly concerned about IT security in Russia, and have been boosting cyber counter-measures.
Practical measure have seen the governing body strengthen online firewalls and introduce encrypted passwords for websites and devices.
Players are also expected to be reminded of existing guidelines relating to their use of social media.
Zoe Kleinman, technology reporter, BBC News
Many cyber attacks are believed to originate in Russia - and sensitive data about upcoming matches would certainly be valuable as it could then be used to place bets on various outcomes.
Once a hacker has access to a Wi-Fi router they can snoop on any of the data being shared on other devices that are connected to it. They can also install a digital backdoor to guarantee re-entry should their access be blocked.
It would also be easy to spoof a free Wi-Fi hotspot, so that the user might think they were logging on via an official platform but what they would actually be doing is opening up their entire device to a scammer.
Messaging apps such as Whatsapp and Signal use end-to-end encryption, which means messages cannot be read if they are intercepted - the players will no doubt be encouraged to communicate using the most secure possible platforms.