For this CrackMe, I was tasked with interacting with and manipulating the given page in such a way that would reveal the "hidden treasure". I used my browser's native tools such as the inspect tool, the JavaScript console, and viewing the page source in order to reverse-engineer the conditions required to reveal the treasure and crack the puzzle. A documentation of the solution as well as my problem-solving process and methodology follows.
Solution
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This crack depends on manipulating your browser's userAgent string and is thus best performed in Firefox, where the userAgent can be manipulated freely and persistently (in Chrome and Chromium-based browsers it can only be changed temporarily while the developer tools are active)
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Modifying the browser's UserAgent
The browser's userAgent string must first be set such that the string 'BLACKSEA' is at index 9 (10th character). This can be done in Firefox by navigating to about:config and adding a string for the general.useragent.override setting, such as 'aaaaaaaaaBLACKSEA'. An example is shown below: