Cross-Domain JavaScript Source File Inclusion

Reference

Plugin Id: 10017 | CWE: 829

Remediation

To mitigate the vulnerability of Cross-Domain JavaScript Source File Inclusion, the following steps can be taken:

Implement Content Security Policy (CSP): Use CSP to restrict the domains from which scripts can be loaded. This can be done by setting the script-src directive to only allow scripts from trusted domains. For example, the following CSP header restricts scripts to be loaded only from the same domain:
```
Content-Security-Policy: script-src 'self';
```
Use Subresource Integrity (SRI): Implement SRI to ensure the integrity of the scripts being loaded. SRI allows you to specify a hash of the script file, and the browser will only execute the script if the hash matches. This prevents any tampering or modification of the script file. For example, the following script tag includes the SRI attribute:
```
<script src="https://example.com/script.js" integrity="sha256-abc123..." crossorigin="anonymous"></script>
```
Avoid using third-party scripts: Whenever possible, host and serve all scripts from your own domain. This reduces the risk of including malicious scripts from third-party domains.

About

Cross-Domain JavaScript Source File Inclusion occurs when a web page includes one or more script files from a third-party domain. This vulnerability can be exploited by an attacker to execute arbitrary code on the victim’s browser, potentially leading to various security risks.

Risks

Including script files from a third-party domain can introduce several risks:

Code Execution: An attacker can inject malicious code into the script file, which will be executed in the context of the victim’s browser. This can lead to various attacks, such as cross-site scripting (XSS) or data exfiltration.
Data Leakage: The third-party script may have access to sensitive information on the web page, such as user credentials or personal data. If the script is compromised, this information can be leaked to the attacker.
Supply Chain Attacks: By including scripts from third-party domains, you are relying on the security practices of those domains. If any of the third-party domains are compromised or have malicious intentions, your website can become a target for supply chain attacks.

It is crucial to implement proper security measures to mitigate the risks associated with Cross-Domain JavaScript Source File Inclusion.