The Cloister Wraiths were, in the Twelfth Doctor's words, like the firewall of the Matrix. (TV: Hell Bent)
The Twelfth Doctor tricked King Hydroflax's body into connecting itself to all of the banks in the Andromeda Galaxy through the universal banking device. This also connected the computer to all of the banks' firewalls which began overloading it. Ramone later told the Doctor that it resulted in the computer being "deleted in a merger." (TV: The Husbands of River Song)
The holograms projected by a colony ship which crashed on the planet Demonese 2 believed that they were real people because of a denial firewall in their coding. (AUDIO: Ghosts)
The Doctor's TARDIS had no firewalls, once resulting in it being flooded by holographic spam due to Rory Williams's usage of a superphone. (COMIC: Spam Filtered) Following the Thirteenth Doctor's regeneration, a Red Supreme Dalek used a fake hologram of the Fourteenth Doctor to deceive Georgy Gold, claiming to have breached the TARDIS firewall to communicate. Georgy, a psychoplasmic construct from a simulacrum of 1966, was unaware of the concept, observing that the TARDIS was not on fire. (COMIC: Liberation of the Daleks [+]Loading...["Liberation of the Daleks (comic story)"])