Until yesterday, a popular networking library for iOS and OS X used in apps such as Pinterest and Simple was susceptible to SSL man-in-the-middle (MiTM) attacks.

The developer behind the framework AFNetworking on Thursday pushed a fix for the issue, a logic flaw.

The flaw had lingered in the wild for more than two months but it took some repeated poking from Github users and two researchers, Simone Bovi and Mauro Gentile at the software security firm Minded Security, for the developer to finally address it. Bovi and Gentile stumbled upon the issue while doing mobile application security analysis for one of their clients in early March.

After combing through the application’s source code the researchers found that the library’s SSL certification validation and its trust evaluation had been disabled, something that could have allowed any SSL traffic to be intercepted via a proxy service such as Burp Suite.

“After a few minutes, we figured out that there was a logical bug while evaluating trust for SSL certificates, whose consequence was to completely disable SSL certificate validation,” Bovi wrote in a blog post yesterday, shortly before the issue was fixed.

Bovi and Gentile found the issue had previously been brought up in a Github forum post in early February and that the flaw appeared to stem from a problem with version 2.5.1 of the library, introduced in late January. An additional, and more thorough post on Github 15 days ago helped the issue gain some visibility as well.

“I have verified that a malicious proxy server can sniff all the contents of HTTPS communication in this case,” Github user duttski, who created a patch as a temporary workaround until the issue was fixed, warned at the time.

iOS developer Mattt Thompson, who created and maintains AFNetworking, pushed Version 2.5.1 of the project live yesterday and fixed the issue by adding test and implementation of strict default validation, according to the library’s release notes.

The library is a key part of popular social media applications like Vine and Pinterest on OS X and iOS. The framework also figures into apps and services primarily used by app and UX developers like Heroku and Parse.

Categories: Mobile Security, Vulnerabilities