Reports involving Yahoo reveals that in 2015 the internet giant agreed to hack all of its user's incoming emails in search for a string of characters in behalf of the US Intelligence Agency. The character strings could lead to identify that the message was produced by particular software or by encryption software used by Al-Qaeda. The surveillance may have shifted with the government's new ways of targeting adversaries.
According to The New York Times, "The bulk scan was conducted pursuant to an order from the secretive Foreign Intelligence Surveillance Court (FISA) and hunted for a "digital signature" associated with a foreign "state-sponsored terror organization." Scanning contents of the message already in a user's inbox is considered surveillance which means that the person is referred to as the target of the surveillance. However, it is different with Upstream where scanning involves message headers, message contents, message to or from and the message containing about the selector. Yahoo's hacking tool is similar to the tool used to identify malware, child pornography and spam.
An individual target might have several associated "selectors" (different email accounts or other digital identifiers), and as the case of Upstream "about collection" shows, the "facility" might be an internet routing switch rather than a particular repository of stored messages associated with that account mentioned by NewsWeek in its report.
The revelation of Yahoo being involved in the government's scanning of targets linked to terrorists sparks questions if it is the only company being asked for such task. According to Sam Biddle of The Interpret, the other internet giants Google, Facebook, Twitter and Apple denied involvement in the "hacking."
Microsoft on the other hand said that it has not engaged in the screening of the email traffic as opposed to what has been reported. The company did not make further comments when asked whether the company received the same request from the government, which leads us to an assumption that they may have received requests but have turned down such orders.
