The WRX has been been blessed with coil on plug technology since it's inception. This means no power robbing spark plug wires in your engine bay that you have to replace every 30,000 miles.
Subaru Coil Pack Repair | There is a downside though. The coil packs are mounted right on the heads of the engine. The very hot engine. Over time, the plastic becomes brittle, and when handled, they break. The electrical connector is even more prone to heat related failures / breakage.
With the earliest models of the WRX being 13 years old now, these types of wear and tear components should be expected. I have seen both the clip on the engine wiring harness and the locking nub on the coil pack break. Neither one is a cheap fix.
- 5250performance Note: If the locking nub breaks off the coil pack, you can at least buy a new coil pack. They're not cheap though, at over $100 each. Don't think you need just one. All 4 have been in the same heat for the same amount of time. If one breaks, plan on replacing the other 3 or at least having a spare on hand.
If the electrical connector on the wiring harness breaks, you have a much more expensive problem. You cannot order just the connector from Subaru, they only sell the entire wiring harness. At a cost of $1000, that's not even an option. I have found a company online that will sell you a replacement connector, for $250.
Subaru WRX repair Coil Pack break | So what do you do if the connector breaks?
The best answer makes me hang my head in shame. While I don't recommend this as a permanent fix, this will get you through the current moment.
You zip-tie the connector for the coil pack repair. Until I am able to find affordable replacement connectors that meet my high standards (meaning OEM performance at a reasonable price), a simple zip-tie is the best quick fix in this scenario.
It's sad to say, but it's true. Long live the zip-tie. Long live duct tape. 
