How do I detect that an iOS app is running on a jailbroken phone?

Question

If I want my app to behave differently on a jailbroken iPhone, how would I go about determining this?

Answer 1

Try executing unsigned code through your application.

A jailbroken devices usually has the following characteristics:

• run unsigned code
• has Cydia installed
• has jailbreak files
• full r/w access to the whole filesystem
• some system files will have been modified (content and so sha1 doesn't match with original files)
• stuck to specific version (jailbreakable version)

Just checking file existence for jailbreak detection is doomed to fail. These checks are easy to bypass.