Insecure direct object references (IDOR) are a type of access control vulnerability that arises when an application uses user-supplied input to access objects directly.
1) Login into your account at demo.usememos.com
2) Turn on your burpsuite proxy
3) Go to archived memos , delete one archived memo and capture the request in your burpsuite
4) Send this request to the repeater and drop the current request
5) Change the Memo ID to victims Memo ID and forward the request
6) You will see that the victims archived memo has been deleted
POC video: https://drive.google.com/file/d/1iiQTBpcwnkXTvmNSdk25wIpBuZ8iRfRd/view?usp=sharing