reCAPTCHA Net Content-Security-Policy Bypass Scanner

reCAPTCHA is widely used by websites and applications to prevent automated bots from accessing their services. It is implemented by developers to safeguard login forms, registration processes, and online polls by requiring users to pass a verification test, typically identifying objects in images. Designed by Google, reCAPTCHA serves both security and usability, functioning as a distinguishing tool between human and machine interactions. The technology is employed across various platforms, including web portals, e-commerce sites, and government services, seeking to enhance user engagement and data protection. Essentially, reCAPTCHA helps in reducing spam and enhancing the user experience by allowing legitimate traffic while blocking malicious access attempts.

The reCAPTCHA Content-Security-Policy (CSP) Bypass vulnerability allows attackers to inject malicious scripts into web pages. This bypass happens when the server improperly configures content security policies, enabling the execution of unauthorized scripts. The flaw can lead malicious actors to execute cross-site scripting (XSS) attacks, stealing sensitive information like credentials and session tokens. Properly configured CSPs are vital in preventing this kind of vulnerability and reducing risks of data and identity theft. Detected vulnerabilities may permit adversaries to manipulate the browsing environment, leading to potential reputational and financial damages for affected organizations.

The vulnerability exploits deficiencies in how the reCAPTCHA script is handled within a website's CSP settings. Specifically, if the CSP is misconfigured, an attacker may use payloads like injecting `<script>` tags to execute a script hosted on `recaptcha.net`. The vulnerable points of such an injection often focus on the query part of URLs, which if not hardened, permit the modification and execution of external scripts. The vulnerability allows bypassing security measures intended to restrict code execution to scripts only from trusted sources, such as Google.com. Strengthening CSP configurations is critical, requiring website administrators to explicitly define the list of trusted sources from which scripts can be loaded and executed.

If exploited, this vulnerability could enable malicious actors to conduct several high-impact attacks. For instance, by injecting harmful scripts, attackers can perform credential theft, impersonate users, or launch client-side denial-of-service attacks. Successful exploitation may result in unauthorized access to user data, potentially leading to data breaches and compromises. Furthermore, users’ trust in the affected applications could decline, impacting the developer's reputation and leading to financial losses. It becomes critical for security teams to fix such vulnerabilities to prevent service disruptions or data exfiltration.

REFERENCES

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