Researchers from two universities in Germany have published a paper on the state of SSL within several Android applications, and the findings were far from positive.
According to their research, many of the tested applications failed to properly implement SSL, leaving millions of users – based on installation figures – exposed to basic Man-In-The-Middle (MITM) attacks.
The six researchers who authored the paper; four from the Leibniz University of Hannover, two from the Philipps University of Marburg, based their findings on the analysis on 13,500 the most popular free applications on Google Play. Of those, eight percent (1,074) contained vulnerable SSL implementations when static testing was performed; with additional issues discovered after manual testing was performed on 100 of them.
In fact, 41 of the manually tested applications collect a substantial amount of personal information, and each one of them is vulnerable to a MITM attack that would harvest said data.
“We could gather bank account information, payment credentials for PayPal, American Express and others. Furthermore, Facebook, email and cloud storage credentials and messages were leaked, access to IP cameras was gained and control channels for apps and re- mote servers could be subverted. According to Google's Play Market, the combined install base of the vulnerable apps in our test set of 100 apps was between 39.5 and 185 million users at the time of writing,” the researchers noted in the paper.
Of the 100 manually tested applications, 21 of them trusted all certificated presented to them, leading them to leak login details, webcam access, Windows Live accounts, PayPal, Diners Club, various banking data, and more. Twenty of the manually tested applications allowed all hostnames, meaning an application that wants something.com will also allow something-else.com. This flaw led to leaked information such as credentials for different services, emails, text messages, contact data, Bitcoin-miner API keys, premium content or access to online meetings, the report notes.
In addition, SSL stripping and lazy use of SSL implementations in general were also a problem. There was also one major issue discovered within Zoner AntiVirus for Android, the researchers explained, as they “successfully manipulated virus signatures downloaded via the automatic update functionality of an anti-virus app to neutralize the protection or even to remove arbitrary apps, including the anti-virus program itself.”
In all the issues discovered within the tested applications impact some 40 to 185 million users, according to Google’s installation figures.
The full report is worth reading for anyone in a development or application security role.