In this talk, I will describe how my team and I systematically exploited around a dozen home-rolled network encryption protocols used by popular mobile apps like RedNote, Alipay, and some of the most popular mobile browsers in China to encrypt sensitive information. I'll demonstrate how network eavesdroppers could access users' browsing history and mobile activity.
This is a systemic issue; despite our work on the above protocols and the resulting vulnerability disclosures, this plague of home-rolled and proprietary encryption is still at large. I will end by discussing how we got here, re-affirm the age-old adage, “Don’t roll your own crypto!”, and call on hackers around the world to help us move towards HTTPS everywhere in understudied app ecosystems.