Security Experts:

SSL Flaw in Intel Crosswalk Exposes Apps to MitM Attacks

Intel has released updates for its Crosswalk framework to address a serious vulnerability that exposes mobile applications to man-in-the-middle (MitM) attacks.

The Crosswalk Project, developed by Intel’s Open Source Technology Center, is a web application runtime that allows developers to use the same codebase to create mobile apps that run on multiple platforms. Crosswalk is compatible with Apache Cordova, Android, iOS and Windows, and it has been used in the development of numerous applications, including ones that have been downloaded millions of times.

While testing one of these apps, namely FastMail for Android, researchers at Nightwatch Cybersecurity discovered a problem with SSL certificates in the Android implementation of Crosswalk.

They found that when an invalid or self-signed SSL certificate is used for communications with the server, an error message is displayed and the user is asked to allow or reject the certificate. If that certificate is allowed, other SSL certificates will be allowed by default without being checked.

“If the user allows the certificate, that choice is remembered going forward and from that point in, all subsequent requests with invalid SSL certificates are accepted by the application, and are not rechecked. This applies even to connections over different WiFi hotspots and different certificates,” Nightwatch Cybersecurity explained in a blog post.

This flaw allows malicious actors to launch MitM attacks and capture potentially sensitive information transmitted by the app using an invalid SSL certificate.

The issue, tracked as CVE-2016-5672, was reported to Intel and the CERT Coordination Center (CERT/CC) in late May. Intel patched the vulnerability last week with the release of versions 19.49.514.5 (stable), 20.50.533.11 (beta), 21.51.546.0 (beta) and 22.51.549.0 (canary). Intel and CERT/CC have published their own advisories.

This is not the first time Nightwatch Cybersecurity has reported finding SSL issues in popular software. Last month, the company disclosed an SSL flaw affecting Silk, a Chromium-based cloud-accelerated web browser running on Amazon’s Kindle Fire tablets and Fire Phones.

Experts discovered that if Kindle users set Google as the default search engine, Silk prevented redirection to the HTTPS version of the website. This allowed hackers to launch MitM attacks an intercept search traffic. Amazon patched the security hole in Silk 51.2.1.

Related Reading: Intel Patches Vulnerability in Driver Update Utility

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Eduard Kovacs (@EduardKovacs) is a contributing editor at SecurityWeek. He worked as a high school IT teacher for two years before starting a career in journalism as Softpedia’s security news reporter. Eduard holds a bachelor’s degree in industrial informatics and a master’s degree in computer techniques applied in electrical engineering.