OpenAI has announced new details about why it took ChatGPT offline on Monday<\/a>, and it\u2019s now saying that some users\u2019 payment information may have been exposed during the incident. <\/p>\n<\/div>\n According to a post from the company<\/a>, a bug in an open source library called redis-py created a caching issue that may have shown some active users the last four digits and expiration date of another user\u2019s credit card, along with their first and last name, email address, and payment address. Users also may have seen snippets of others\u2019 chat histories as well.<\/p>\n<\/div>\n This isn\u2019t the first time caching issues have caused users to see each other people\u2019s data \u2014 famously, on Christmas Day in 2015, Steam users were served pages with information from other users\u2019 accounts<\/a>. There is some irony in the fact that OpenAI puts a lot of focus and research into figuring out the potential security and safety ramifications of its AI, but that it was caught out by a very well-known security issue.<\/p>\n<\/div>\n The company says the payment info leak may have affected around 1.2 percent of ChatGPT Plus who used the service between 4AM and 1PM ET on March 20th. <\/p>\n<\/div>\n You were only affected if you were using the app during the incident.<\/p>\n<\/div>\n<\/div>\n There are two scenarios that could\u2019ve caused payment data to be shown to an unauthorized user, according to OpenAI. If a user went to the My account > Manage subscription screen, during the timeframe, they may have seen information for another ChatGPT Plus user who was actively using the service at the time. The company also says that some subscription confirmation emails sent during the incident went to the wrong person and that those include the last four digits of a user\u2019s credit card number.<\/p>\n<\/div>\n The company says it\u2019s possible both these things happened before the 20th but that it doesn\u2019t have confirmation that ever happened. OpenAI has reached out to users who may have had their payment information exposed.<\/p>\n<\/div>\n As for how<\/em> this all happened, it apparently came down to caching. The company has a full technical explanation in its post<\/a>, but the TL;DR is that it uses a piece of software called Redis to cache user information. Under certain circumstances, a canceled Redis request would result in corrupted data being returned for a different request (which shouldn\u2019t have happened). Usually, the app would get that data, say, \u201cthis isn\u2019t what I asked for,\u201d and throw an error. <\/p>\n<\/div>\n But if the other person was asking for the same type of data \u2014 if they were looking to load their account page and the data was someone else\u2019s account information, for example \u2014 the app decided everything was fine and showed it to them. <\/p>\n<\/div>\n That\u2019s why people were seeing other users\u2019 payment info and chat history; they were being served cache data that was actually supposed to go to someone else but didn\u2019t because of a canceled request. That\u2019s also why it only affected users who were active. People who weren\u2019t using the app wouldn\u2019t have their data cached. <\/p>\n<\/div>\n What made things really bad was that, on the morning of March 20th, OpenAI made a change to its server that accidentally caused a spike in canceled Redis requests, upping the number of chances for the bug to return an unrelated cache to someone.<\/p>\n<\/div>\n OpenAI says that the bug, which appeared in one very specific version of Redis, has now been fixed and that the people who work on the project have been \u201cfantastic collaborators.\u201d It also says that it\u2019s making some changes to its own software and practices to prevent this type of thing from happening again, including adding \u201credundant checks\u201d to make sure the data being served actually belongs to the user requesting it and reducing the likelihood that its Redis cluster will spit out errors under high loads.<\/p>\n<\/div>\n While I\u2019d argue that those checks should\u2019ve been there in the first place, it\u2019s a good thing that OpenAI has added them now. Open source software is essential for the modern web, but it also comes with its own set of challenges; because anyone can use it, bugs can affect a wide number of services and companies at once<\/a>. And, if a malicious actor knows what software a specific company uses, they can potentially target that software to try and knowingly introduce an exploit. There are checks that make doing so harder<\/a>, but as companies like Google have shown<\/a>, it\u2019s best to work to make sure it doesn\u2019t happen<\/a> and to be prepared for it if it does.<\/p>\n<\/div>\n<\/div>\n