Intro: Security issues are important, whether you're a small startup or a major tech company. Likewise, a security researcher is always a researcher, even when searching for a life partner. 😉 Yes, you read that right. I discovered an Insecure Direct Object Reference (IDOR) vulnerability on one of the most popular matrimony websites while browsing profiles for myself. A Tale of Two APIs The website had secured its APIs properly. However, the mobile APIs were left exposed without the same level of protection. One of the key features on this platform is "Favorite Profiles" , where users can shortlist others who match their preferences. While exploring the app using mitmproxy , I noticed that the mobile and web platforms were calling two different APIs. The mobile version was passing the current user's ID as a parameter , which immediately raised a red flag. Digging Deeper, Ethically As a responsible white-hat hacker, I didn't want to compromise anyone's...