Inclusion of Functionality from Untrusted Control Sphere

Description

JavaScript or CSS source files are included from third party domains without Sub-Resource Integrity (SRI). If an attacker were to compromise the sites hosting these third party resources, they could inject malicious script or CSS data in an attempt to compromise users of your application. However, if SRI was applied and an attacker attempted to modify the contents of the script, the browser would not load the script and your applications users would be protected from the malicious alterations.

Remediation

All identified resources should be sourced from the same domain as the target application. If this is not possible, it is strongly recommended that all script tags that implement src values, or link tags that implement the href values include Sub-Resource Integrity. To generate SRI integrity values the srihash tool can be used, or by running one of the following commands:

• cat FILENAME.js | openssl dgst -sha384 -binary | openssl base64 -A
• shasum -b -a 384 FILENAME.js | awk '{ print $1 }' | xxd -r -p | base64

The output of these tools must be added as additional attributes, in particular: integrity and either crossorigin=anonymous or crossorigin=use-credentials. An example of a valid SRI protected script tag can be found below:

<script src="https://example.com/example-framework.js"
    integrity="sha384-oqVuAfXRKap7fdgcCY5uykM6+R9GqQ8K/uxy9rx7HNQlGYl1kPzQho1wx4JwY8wC"
    crossorigin="anonymous"></script>

Details

Links

• OWASP
• CWE
• MDN