Offensive programs are the standard method of hacking a network. Using attacks such as Beam Cannon, Worms and even a mighty Kraken, a player can overwhelm any Security Nodes placed on a network by force. This method of attacking is referred to as using "Brute Force" and differs significantly from the more subtle Stealth attacks.
Different programs have different methods of attack, with some programs also having additional special abilities. When an offensive program has a choice of which node to attack, most programs select a target using the following criteria.
WARNING: This list is based on current observations. While not guaranteed to be 100% accurate, it has proven to be correct most of the time. (See current discussion in comments.) The in-game priorities differ from what is intended, and will be amended in a future update. .
- Active Security Nodes - (Sentry, Turret, Black ICE). Other Security Nodes (Guardian, Scanner and Code Gate) are considered regular nodes in this regard.
- The Core.
- Black Nodes - Nodes with an installed antivirus.
- Partially Black Nodes - Nodes where an antivirus is currently being loaded.
- White Nodes - Nodes where an antivirus is not present.
- Nodes under the Wraith effect.
If connected nodes fall under the same category, the order in which nodes are connected takes precedence, with nodes that are connected first having priority over nodes which are connected last. 
- Credit to Wakaka, Love.Wolf and Invictus - thanks!
Programs that fire projectiles such as Blasters and Worms can change targets during an attack if a connected node with a higher priority is reclaimed by the defender. Channeled attacks such as the Beam Cannon will select a target and remain targeting that node until either itself or its target is compromised, regardless of changes to its surroundings.
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