No

A cyber attack is a cyber operation, whether offensive or defensive, that is reasonably expected to cause injury or death to persons or damage or destruction to objects.

Michael Schmitt et al; Tallinn Manual 1.0, pp 92
  • Cyber Operation?
  • Expected to cause death or injury to people or damage to objects?
Russian Espionage and Leak of DNC Emails does not match this definition. Here's a list of actual cyberattacks and and why this matters.

What happened?

Forensic evidence points to Russian intelligence agencies as responsible for the release of 20,000 emails from the Democratic National Committee.