While developing a tool for evaluating mobile application security, researchers at Sudo Security Group Inc. found out something unexpected. Seventy-six popular applications in Apple's iOS App Store, they discovered, had implemented encrypted communications with their back-end services in such a way that user information could be intercepted by a man-in-the-middle attack. The applications could be fooled by a forged certificate sent back by a proxy, allowing their Transport Layer Security to be unencrypted and examined as it is passed over the Internet.
The discovery was initially the result of bulk analysis done by Sudo's verify.ly, a service that performs bulk static analysis of application binaries from Apple's App Store. Will Strafach, president of Sudo, verified the applications discovered by the system were vulnerable in the lab, using a network proxy configured with its own Secure Socket Layer certificate.