Yahoo reportedly built software to scan incoming emails for US intelligence officials

According to Reuters, Yahoo built software in 2015 to “search all of its customers’ incoming emails” for U.S. intelligence officials.

The report states that Yahoo had scanned hundreds of millions of its customers emails to comply with request by the FBI. Reports indicate that this is the first case of an internet company agreeing to spy on its users to comply with a National Security Agency (NSA) request.

What information the intelligence agency was searching for is still unclear, though it has been revealed that Yahoo was tasked to look for a specific set of characters. What may have been handed over is also unknown.

While this may be the first known case, U.S. Internet companies have been known to hand over user information in bulk to comply with requests from federal intelligence agencies.

Reuters reports that the FBI likely approached other internet companies with the same demand since they did not know which email accounts were being used by the agency’s target. Whether the demand went to other companies has not been confirmed, nor has whether or not these requests were complied with.

Under laws such as the 2008 amendments to the Foreign Intelligence Surveillance Act (FISA), federal agencies can ask internet companies to provide customer information for a wide range of uses, but primarily for use in terrorism investigations.

Representatives from FISA told Reuters that Yahoo could have fought the 2015 request on at least two grounds. Similar requests of other companies have surfaced in recent months, namely Apple, who fought the FBI on their request.

This case refers to the FBI’s request for Apple to unlock the San Bernardino shooter’s phone, which Apple refused until the FBI found another way to do so and eventually dropped their request.

Yahoo CEO Melissa Mayer and her team apparently chose to comply with the directive rather than fight it for fear that they would lose. Yahoo challenged a similar directive in 2007, which records show was unsuccessful.

The Yahoo CEO and her general counsel did not involve the security team with the issue, rather having the engineering team write a program to siphon off emails with the characters the FBI was searching for.

Yahoo is currently in the midst of trying to complete a $4.8 billion acquisition deal with Verizon as their security continues to be questioned. Furthermore, the internet company just weathered a scandal involving the hacking of over 500 million of its users’ accounts.

Related: Yahoo confirms data breach in 2014 that affects over 500 million accounts