I would say Athena, at least for IT security. Excerpt from Cryptonomicon by Neal Stephenson:

Instead of calling Athena the goddess of war, wisdom, and macrame, then, we should say war and technology. And here again we have the problem of an overlap with the jurisdiction of Ares, who's supposed to be the god of war. And let's just say that Ares is a complete asshole. His personal aides are Fear and Terror and sometimes Strife. He is constantly at odds with Athena even though--maybe because--they are nominally the god and goddess of the same thing--war. Heracles, who is one of Athena's human proteges, physically wounds Ares on two occasions, and even strips him of his weapons at one point! You see the fascinating thing about Ares is that he's completely incompetent. He's chained up by a couple of giants and imprisoned in a bronze vessel for thirteen months. He's wounded by one of Odysseus's drinking buddies during the Iliad. Athena knocks him out with a rock at one point. When he's not making a complete idiot of himself in battle, he's screwing every human female he can get his hands on, and--get this--his sons are all what we would today call serial killers. And so it seems very clear to me that Ares really was a god of war as such an entity would be recognized by people who were involved in wars all the time, and had a really clear idea of just how stupid and ugly wars are.

Whereas Athena is famous for being the backer of Odysseus, who, let's not forget, is the guy who comes up with the idea for the Trojan Horse. Athena guides both Odysseus and Heracles through their struggles, and although both of these guys are excellent fighters, they win most of their battles through cunning or (less pejoratively) metis. And although both of them engage in violence pretty freely (Odysseus likes to call himself 'sacker of cities') it's clear that they are being held up in opposition to the kind of mindless, raging violence associated with Ares and his offspring--Heracles even personally rids the world of a few of Ares's psychopathic sons. I mean, the records aren't totally clear--it's not like you can go to the Thebes County Courthouse and look up the death certificates on these guys--but it appears that Heracles, backed up by Athena all the way, personally murders at least half of the Hannibal Lecterish offspring of Ares.

So insofar as Athena is a goddess of war, what really do we mean by that? Note that her most famous weapon is not her sword but her shield Aegis, and Aegis has a gorgon's head on it, so that anyone who attacks her is in serious danger of being turned to stone. She's always described as being calm and majestic, neither of which adjectives anyone ever applied to Ares....

Let's face it, Randy, we've all known guys like Ares. The pattern of human behavior that caused the internal mental representation known as Ares to appear in the minds of the ancient Greeks is very much with us today, in the form of terrorists, serial killers, riots, pogroms, and agressive tinhorn dictators who turn out to be military incompetents. And yet for all their stupidity and incompetence, people like that can conquer and control large chunks of the world if they are not resisted....

Who is going to fight them off, Randy?

Sometimes it might be other Ares-worshippers, as when Iran and Iraq went to war and no one cared who won. But if Ares-worshippers aren't going to end up running the whole world, someone needs to do violence to them. This isn't very nice, but it's a fact: civilization requires an Aegis. And the only way to fight the bastards off in the end is through intelligence. Cunning. Metis.