Once again Android apps are under scrutiny, this time following the discovery that a large number of them are open to man-in-the-middle attacks.
Security firm FireEye tested the 1,000 most popular Android apps in the official Google Play store and found that a ‘significant portion of them are susceptible to MITM attacks’ because of SSL errors. SSL (Secure Sockets Layer) allows apps to communicate securely with remote servers.
“The Android ecosystem is all about communicating, and right now it’s screaming for help,” said FireEye. “That’s because SSL vulnerabilities and the Man-In-The-Middle (MITM) attacks they enable are wreaking havoc on data security.”
Three SSL security errors were checked:
- Trust managers that don’t check the validity of digital certificates.
- Apps which fail to verify if the hostname of the remote server is correct.
- Code that ignores SSL errors when using Webkit.
The most common of the three is the issue with trust management. When this vulnerability is targeted, an app can wrongly appear to be a legitimate system and grab hold of data it shouldn’t. This vulnerability is present in 73% of the top 1,000 android apps and 40% of the top 10,000.
The second most common flaw was Webkit errors, affecting 77% of the top 1,000 apps and 13% of the top 10,000. Hostname checking errors were in the single figures for both test groups.
“Many issues in SSL and cryptography arise from how applications are tested and released. During development, many software shops find it useful to disable normal validation of SSL to facilitate testing,” said Patrick Thomas, security consultant at Neohapsis.
“This is a dangerous practice because it requires that someone remembers to turn it back on before shipping – an easy mistake to make with huge consequences. This sort of research highlights the importance of having security expertise tightly integrated with development teams, and performing specific security testing (in addition to functional testing) before release.”