Even the US military is not safe against cyber vandalism. It was a rather embarrassing moment when at least two of their social media channels, Twitter and YouTube, became vulnerable against hackers.
While it was confirmed that none of the documents released via the said sites are classified, the incident was considered to be a lesson learned and made the military more aware of the importance of staying safe on the internet especially with their job to secure the country. Tougher security steps and changing the passwords of their social media accounts were implemented right away to avoid the same thing happening again.
Source: Wall Street Journal