The OWASP Mobile Security Testing Guide -- https://www.owasp.org/index.php/OWASP_Mobile_Security_Project#tab=Mobile_Security_Testing UPDATE -- here -- https://docs.google.com/document/d/1N7zMXlFHtWfc00xa6lRHnVB60U4BZO4SbUrWYMbojVM/edit?usp=sharing
(a link to the GDocs file as well as a huge overview)