Definition: In this task, you need to generate an appropriate title for the given summary of some paragraph. The generated title must be short and should include the main topic of the given text. Your summary should be less than 20 words long.
Input: More than 1,000 energy companies in North America and Europe have been compromised in a huge malware attack unearthed by US security firm Symantec.

Energy firms hacked by 'cyber-espionage group Dragonfly'