Security Vulnerabilities in Apache Cordova / PhoneGap

Type securityvulns
Reporter Securityvulns
Modified 2014-02-03T00:00:00


The following email was sent to Apache Cordova/PhoneGap on 12/13/2013, and again on 1/17/2014. As there has been no response, we are re-posting it here to alert the general public of the inherent vulnerabilities in Apache Cordova/PhoneGap.

Dear PhoneGap contributors,

PhoneGap’s domain whitelisting for accessing native resources is broken and can be bypassed. These vulnerabilities can be exploited by any third-party domain loaded inside an iframe (e.g., malicious ad scripts). Below, we give a brief summary of the vulnerabilities. You can find more details in the paper <>.

  1. Domain whitelisting on Android (before API 11) and Windows Phone 7 and 8 relies on the URL interception call that does not intercept iframe and XMLHttpRequest URLs. Consequently, it does not restrict which domains can be loaded in iframes. Any script inside an iframe can directly use PhoneGap’s internal JavaScript interfaces to the Java objects and access native resources: for example, by calling execute = cordova.require('cordova/exec'); var opts = cordova.require ('cordova/plugin/ ContactFindOptions' ); and directly operating on these objects.

  2. A malicious script running in an iframe can dynamically choose any of PhoneGap’s vulnerable bridge mechanisms at runtime (e.g. addJavascriptInterface or loadUrl on Android) and use it to bypass the domain whitelist. We call this the chosen-bridge attack.

  3. PhoneGap’s whitelisting check on Android is incorrect - it misses an anchor at the end of the regular expression: this.whiteList.add(Pattern.compile("€https?://(.*\\.)?" + origin));

For example, if is whitelisted, will pass the check.

  1. PhoneGap’s domain whitelisting on Android (API 11 or highler) and iOS does not adhere to the same-origin policy. Third-party scripts included using <script> tags are blocked unless their source domain is whitelisted, even though these scripts execute in the origin of the hosting page, not their source origin.

  2. Instead of just blocking access to bridges from non-whitelisted domains, PhoneGap completely blocks these domains from being loaded in the browser. This prevents ad-supported apps from displaying third-party ads and destroys the look-and-feel of many Web pages.

We have a proof-of-concept implementation (a 400-line patch for PhoneGap 2.9.0 on Android) called NoFrak [] which fixes these vulnerabilities. NoFrak does not allow Web content from non-whitelisted domains to access native resources but still displays it correctly in the browser. If you are interested in discussing how to merge NoFrak or some parts of NoFrak to PhoneGap’s main branch, please let us know.


Martin, Suman, and Vitaly