IDOR (Identity-Based Data Exposure) vulnerabilities are a significant threat in web and mobile applications, offering higher impact and paying potential than other types of bugs. An IDOR vulnerability occurs when an attacker can access, edit or delete another user's objects by changing the values of variables such as "id", "pid", and "uid". Understanding application flows, identifying injection points, and using tools like Burp Suite are essential for finding and exploiting these vulnerabilities. Blind IDOR cases can be particularly challenging to detect, but combining them with other vulnerabilities can increase their impact. Critical IDORs pose a significant risk in areas such as password reset and account recovery, while HPP (HTTP Parameter Pollution) testing can help identify vulnerabilities. To prevent IDOR vulnerabilities, it's crucial to control API requests, provide permissions for endpoints, and use hash functions to make attackers' jobs harder. By understanding the impact of IDOR vulnerabilities and taking proactive measures, developers can significantly reduce their occurrence.