Today we’re sharing that we’ve recently seen significant cyber activity by a threat group we call Phosphorus, which we believe originates from Iran and is linked to the Iranian government. We’re sharing this for two reasons. First, it is important that we all – governments and private sector – are increasingly transparent about nation-state attacks and efforts to disrupt democratic processes. Second, while we have processes to notify customers about nation state activity and have AccountGuard to monitor accounts of campaigns and other associated organizations related to election processes in democracies around the world, publishing this information should help others be more vigilant and take steps to protect themselves.
In a 30-day period between August and September, the Microsoft Threat Intelligence Center (MSTIC) observed Phosphorus making more than 2,700 attempts to identify consumer email accounts belonging to specific Microsoft customers and then attack 241 of those accounts. The targeted accounts are associated with a U.S. presidential campaign, current and former U.S. government officials, journalists covering global politics and prominent Iranians living outside Iran. Four accounts were compromised as a result of these attempts; these four accounts were not associated with the U.S. presidential campaign or current and former U.S. government officials. Microsoft has notified the customers related to these investigations and threats and has worked as requested with those whose accounts were compromised to secure them.
Phosphorus used information gathered from researching their targets or other means to game password reset or account recovery features and attempt to take over some targeted accounts. For example, they would seek access to a secondary email account linked to a user’s Microsoft account, then attempt to gain access to a user’s Microsoft account through verification sent to the secondary account. In some instances, they gathered phone numbers belonging to their targets and used them to assist in authenticating password resets.
While the attacks we’re disclosing today were not technically sophisticated, they attempted to use a significant amount of personal information both to identify the accounts belonging to their intended targets and in a few cases to attempt attacks. This effort suggests Phosphorus is highly motivated and willing to invest significant time and resources engaging in research and other means of information gathering.