GitHub Gist Content-Security-Policy Bypass Scanner

GitHub Gist is a popular platform used by developers and organizations worldwide for sharing code snippets, patches, and notes. It serves as a lightweight alternative to repositories, helping in quick code sharing and collaboration. Many developers use GitHub Gist to host small scripts or configuration files that can be easily embedded in websites. The platform is preferred due to its integration with GitHub's ecosystem, providing a seamless experience for existing GitHub users. However, its open nature requires adequate security controls to prevent exploitation. Maintaining a robust content security policy is critical for users to ensure their code shares remain safe.

The vulnerability detected by this scanner involves a bypass of Content Security Policy (CSP) restrictions in GitHub Gist environments, leading to potential Cross-Site Scripting (XSS) attacks. CSP is meant to act as a safeguard against XSS by specifying domains from which resources can be loaded. When a CSP bypass occurs, it allows potential attackers to inject malicious scripts, compromising the integrity and security of the affected web application. Such a vulnerability is significant in environments where sensitive data is handled, as it can lead to unauthorized access or data theft.

Technical details of the vulnerability involve improper handling of CSP headers, which can be manipulated to allow execution of unauthorized scripts. In this scenario, the vulnerable endpoint could involve URLs or paths within GitHub Gist where the policy is expected to be enforced but can be bypassed. An attacker could inject scripts through specially crafted URLs or query parameters, exploiting this weakness to perform arbitrary actions within the user's browser. Key areas of concern include any endpoint not strictly validating CSP rules and effectively whitelisting only trusted sources.

Exploiting this vulnerability could allow attackers to execute scripts in the context of another user, potentially leading to session hijacking, data theft, or defacement of the user's account and data. Such an attack could undermine user trust and integrity of shared code resources. In organizations, it can result in sensitive data being exposed to unauthorized parties and subsequent compliance violations. Timely detection and remediation are crucial to prevent any security breaches arising from this vulnerability.

REFERENCES

• https://github.com/renniepak/CSPBypass/blob/main/data.tsv