Official Steatment from RockstarGames:
In recent weeks, a small number of Grand Theft Auto Online players sought to exploit the game by generating and distributing game-breaking amounts of in-game cash, disrupting the experience for other players.
We will continue to issue title updates on an ongoing basis to counter the negative impact this has had on gameplay, and as part of today’s maintenance period, we are removing the counterfeit GTA$ from the game’s economy. Anyone that innocently received GTA$ as a result of these exploits but did not engage in cheating to acquire it will not face any further action – the funds will just be removed , and you’ll be able to keep any items you currently own.
Those who actively engaged in cheating and exploiting the game in this manner will, however, be subject to in-game penalties at our discretion. This may include being placed in isolated cheater pools or banned from GTA Online altogether.
Should you ever encounter someone in GTA Online that appears to be taking advantage of exploits in your session, we ask that you alert us directly via the in-game reporting functionality. In the Pause menu, under the Online tab, select Players and scroll to the offending player. From there, select Report and choose Exploits from the violation options.
We’re grateful for the community’s continued support in dealing with these issues and once again apologize to anyone that has had their Grand Theft Auto Online experience sullied by these exploits that broke the game’s natural flow. Please stay tuned for lots more news about GTA Online in the weeks ahead.
We’re happy to report this maintenance has now been completed and Grand Theft Auto Online is back up and running. Thanks again everyone for your patience.