Greyball is a software tool used by the ride-hailing service Uber to identify and deny service to certain riders, including riders who Uber suspects of violating its terms of service.
Uber's use of Greyball was made public in a March 3, 2017, investigative report by The New York Times, which described how, as early as 2014, Uber had used Greyball to evade local government authorities in the United States, Australia, South Korea, and China. In the days following the publication of the New York Times story, Uber admitted that it had used Greyball to thwart government regulators and it promised to stop using the tool for that purpose.
Uber reportedly developed Greyball to identify individuals who Uber suspected of using its service improperly, and it began using the tool as early as 2014. According to Uber, Greyball can "hide the standard city app view for individual riders, enabling Uber to show that same rider a different version." Uber claimed that it used Greyball to deny service to individuals suspected of violating the company's terms of services, such as people seeking to harm Uber drivers, disrupt Uber operations, or carry out law enforcement actions against Uber drivers. However, after The New York Times revealed Greyball's existence in March 2017, Uber said it would stop using it to evade local government regulators.
According to the New York Times report, which was based on interviews of four current and former Uber employees and a review of internal Uber documents, Greyball used several methods to identify and deny service to government officials who were investigating Uber for violations of local laws. Those methods included:
* Geofencing. Uber would create a digital map that identified the locations of city government offices. If a potential rider attempted to hail a ride from the area around a government building, Greyball would flag the individual as a possible law enforcement agent.
* Mining credit card databases. If Uber identified a credit card as being associated with a government agency or police union, it would flag that individual in Greyball.
* Identifying devices. Since government agencies would often buy cheap cellphones for use in sting operations, Uber employees would visit electronics stores to obtain model numbers for inexpensive phones and input those model numbers into Greyball.
* Searches of social media. Uber employees searched social media profiles to identify possible law enforcement agents. Uber then flagged those individuals in Greyball.
* Eyeballing. Greyball would determine if a potential rider had been opening and closing the Uber app numerous times without calling for a ride.
In May 2017, several news organizations reported that the United States Department of Justice had opened a criminal investigation into Uber's use of Greyball to avoid local law enforcement operations.
Transport for London (TfL) cited use of Greyball in London as one of the reasons for its decision not to renew Uber's private hire operator licence. The decision states that the way in which Uber uses Greyball contributes to it failing to meet the standards of a "fit and proper" private hire operator.
Consequently, Uber would not be able to operate legally in London after its licence expired on 30 September 2017 unless they entered an appeal within 21 days. Uber challenged the ban in court and are currently still working even though they've been cited as not fit and proper by the licensing authority.