A security memo from the FBI and Department of Homeland Security has warned of the dangers from a high-tech attack against crowds flocking to Silicon Valley for this year's Super Bowl jamboree.

The climactic game will be held in the San Francisco 49ers stadium in Santa Clara on February 7, although there will be a series of events in San Francisco and the Valley to commemorate the runny, kicky, throwy version of football favored by the rebellious colonies. But the memo says the technologically sophisticated location may cause problems.

Over the last year there have been over 20 attacks on the area's fiber optic network, with deliberate but seemingly random line severings taking place, usually at night. The memo, obtained by NBC, warns these could have been a drill for a terrorist attack.

The outage attacks "raise the concern individuals may be using these incidents to test and prod network durability in conjunction with a more complex plot," the memo said.

It's possible that if a terrorist attack was to occur, the fiber optic network that backs up communications systems used by the emergency services could be tampered with to slow down response times and induce more panic.

Another piece of tech the Feds will be keeping an eye on is drones. California has many private drone operators and the possibility of having the hardware flying about is also causing concern, with the memo stating that they could be used by "malicious actors."

"[Drones] may present a low-altitude hazard to aviation assets supporting the event, allow unauthorized video coverage of events, or pose a risk of injury to event-goers if an operator loses control of a [drone]," according to homeland security analysis. ®