I've been reading some material on the sandbox, and while you seem to be able to disable errant emails escaping the sandbox, i haven't seen anything (yet) about whether anything else represents a danger, such as an outbound message off workflow, or an apex HTTP request. Does the sandbox also copy apps(?), and if so, is there any risk of these having integrations with external systems that might interfere with production data indirectly? ta.
Yes, you can definitely cause harm from a sandbox, especially in a full sandbox. You could trigger an integration with sandbox data, or email a customer from a sandbox, send outbound messages, etc.
Check this answer :