Uber has been using a secretive tool to evade authorities for years, particularly at times when city regulators were trying to block the ride-hailing service, according to a new report by the New York Times' Mike Isaac.

Called Greyball, the tool collected data from Uber's app to identify and evade officials in cities like Boston, Paris, and Las Vegas. The Times reports that the program was used in markets where Uber was outright banned or being resisted by law enforcement.

Current and former Uber employees provided documentation to the Times of Greyball's use.

Uber provided the following comment to Business Insider:

"This program denies ride requests to fraudulent users who are violating our terms of service -- whether that’s people aiming to physically harm drivers, competitors looking to disrupt our operations, or opponents who collude with officials on secret ‘stings’ meant to entrap drivers," the company said.

Uber reportedly started using Greyball as early as 2014 and is still in use today. Greyball is part of a larger program called VTOS, or “violation of terms of service,” that allows Uber to suss out people thought to be targeting the ride-hailing service improperly.

The VTOS program and the Greyball tool used techniques like looking at a user's credit card information and seeing if it was tied to an institution, such as a police credit union, to identify authority figures, according to the report.

The news comes at a time where Uber is under scrutiny after Susan Fowler, a former Uber engineer, wrote in a blog post that she faced sexism and gender bias in the workplace.


This post originally appeared on Business Insider.