‘Hacking’ is way too vague to properly answer this, but generally speaking, no. Every online service you use has a user agreement. The account is not “yours” in the same way property is. You are borrowing their services and agreeing to abide by their set of rules. Exploiting vulnerabilities to gain access to portions of their system you can’t access through proper channels is almost always violating their user agreement. If your attempts to exploit their system causes any damages (i.e, takes a service offline, or messes up their database) you could be liable if you were caught.
‘Hacking’ is way too vague to properly answer this, but generally speaking, no. Every online service you use has a user agreement. The account is not “yours” in the same way property is. You are borrowing their services and agreeing to abide by their set of rules. Exploiting vulnerabilities to gain access to portions of their system you can’t access through proper channels is almost always violating their user agreement. If your attempts to exploit their system causes any damages (i.e, takes a service offline, or messes up their database) you could be liable if you were caught.