Microsoft acquired Yammer in July 2012 for $1.2 billion and has spent the last year building out a solid road map. Aside from growing the user and features base, Microsoft has also helped secure Yammer.
A security report from researchers at Vulnerability Laboratory this week, details a remote authorization bypass vulnerability in Yammer. The vulnerability potentially could have been exploited by a remote attacker without having a privileged application user account or there being any user interaction. The flaw was related to an insecure implementation of the OAuth authorization technology Yammer uses.