The Iranian government abused well-known vulnerabilities in global telecommunications infrastructure to locate US military personnel in the run-up to the Iran war, as well as in the early days of the conflict, according to the Financial Times.

The Iranian government leveraged Signaling System 7, or SS7, a set of protocols for 2G and 3G networks that has long been the backbone of how cellular networks connect to each other to route calls and text messages from subscribers around the world, the newspaper reported, citing research by the Mobile Surveillance Monitor as well as unnamed government officials with knowledge of the spying campaign.

Intelligence agencies have long abused SS7 to track mobile phones abroad, which is what happened in this campaign.

Using this technique, Iran was allegedly able to locate US military forces stationed at military bases as well as hotels in Iraq, Bahrain and other Middle Eastern countries, allowing the regime to attack them. These attacks resulted in several injuries.

In addition to SS7, Iran also abused advertising technology used to serve personalized ads to mobile phone users, another well-known surveillance technique that relies on everyday technology.