What is Undef?
Undef aka Undefined primarily functions as a feature-rich CC checker but also offers cards and dumps. Undef is one of the few sites that offer dumps with pin codes – if you have card writing equipment you can use these datasets to write your own cards to get cash from an ATM. You can find the onion link for the Undef Checker and Card Shop to the right of this article.
Registration is easy and straight-forward, you don’t need to state any additional information except a username and password. Once you have signed up, you will have instant access to all features of the site, there is no minimum deposit requirement. When you want to deposit, the only accepted currency on Undef is Bitcoin.
As stated above, the primary function of the site is the CC checker. It is fairly powerful compared to the checkers of other sites: There are two checkers, the normal CC checker and a checker for Track2 data. Both can be used in two modes: “Authorize”, which is the standard checker for all cc systems, and “Pre-Authorize” which will check a card without any charges to the card holder’s account. Undefined also offers an AVS checker, dumps checker and API checker. Checks can be done for Visa, Mastercard, American Express, and Discovery cards but pre-auth checks cannot be performed on AMEX cards. All checks cost a flat amount of 0.21 USD.
In the Tracks2 section you can buy single credit cards with full Track2 information. Probably more interesting might be the “Secret” section which contains dumps including PIN codes for cards. These are relatively rare and not offered on many other sides because if you have card writing equipment, you can write out your own cards using this data and subsequently use the card to withdraw money from any ATM.
Same as with all darknet sites the usual security recommendations apply. Most importantly: stay anonymous. Use the TOR browser only and don’t use the TOR browser for any regular (non-darknet) browsing.
Ideally, you have a dedicated system or at least a dedicated VM for all your darknet activities. Keep your darknet PGP keys and other credentials limited to that system only, do not mix it with any activities that would expose your identity.
Treat your dedicated system like a work-system: Only install the software necessary for your operations do not install anything for entertainment or other purposes. Subsequently, resist the urge to browse Twitter, Reddit or any other social media sites while you have downtime. For this always use your regular system.
For additional system security, we recommend you run a secure operating system like Tails or Whonix on your dedicated system for darknet activities. We also recommend using a VPN as an additional security measure since TOR will only anonymize your browsing sessions but not other traffic.
Especially when using any public WiFi hotspots you should always use a VPN when accessing the Internet since you don’t know whether the access point is compromised. A VPN ensures that all of your traffic, no matter what application, will always be strongly encrypted when passing the access point, this protecting yourself not only from eavesdropping but also possible identity theft.
Undef aka Undefined should be your go-to site whenever you need to do extensive checks on credit cards. It is also very useful if you need a secondary checker to verify your results. With the many additional features of the checker, you can verify certain data you can’t use with other tools. Another useful resource on the site is the dumps section that offers credit cards with PIN information. As always, when visiting any darknet vendor shop make sure to only use trusted links, such as the onion link for the Undefined CC Checker and card shop on the top right.