Cxense API Content-Security-Policy Bypass Scanner

Cxense API is a service utilized by various digital content managers and advertisers to deliver personalized online experiences. It plays a significant role in collecting and analyzing audience data to offer tailored content and advertisements. This API is often embedded in websites and digital platforms to improve user engagement and retention. Companies operating large-scale content delivery networks and advertising platforms use Cxense API to refine their targeting strategies. The API collects user behaviors and segments audiences based on their interactions with the site. Businesses leveraging such technologies aim to enhance user experience while fostering a deeper connection with their online customers.

The Content-Security-Policy (CSP) Bypass vulnerability in the Cxense API allows attackers to inject scripts and potentially execute arbitrary actions on the victim's browser. This vulnerability arises when input validation is insufficient and user inputs directly affect document execution contexts. The bypass could lead to the execution of unintended scripts, compromising user data confidentiality and integrity. It targets the way browsers enforce CSP, allowing malicious actors to override restrictions set by the website owners. This can enable Cross-Site Scripting (XSS) attacks, where victims unknowingly execute scripts that siphon data or engage in further malicious actions. The vulnerability fundamentally impacts the browser's trust model, potentially rendering protections around sensitive operations ineffective.

In this scenario, the vulnerability hinges on manipulating query parameters used by the Cxense API, particularly by injecting scripts within the endpoint paths. An identified script injection vector leverages the callback function parameter in API requests to introduce malicious payloads. The script tag with a callback function, once injected, leads to execution in the context of the victim's session. The vulnerability might not be captured by usual CSP directives, allowing the injected scripts to bypass the security header. By exploiting this weakness, attackers can launch further sophisticated operations by chaining vulnerabilities. The exposed endpoints and insufficient CSP implementations form the core technical lapse leading to this bypass.

When exploited, this vulnerability can severely compromise session integrity, leading to unauthorized transactions or disclosures of sensitive user data. Users might encounter altered page content or face redirections that inject further malicious content. Beyond individual user impacts, compromised Cxense API instances can affect entire platforms, degrading service trustworthiness. Also, the trust violation risk extends to privacy breaches, causing legal and reputational consequences for organizations. Continued exploitation can grant attackers persistent access to update and manipulate web functionalities as long as the CSP bypass remains unaddressed. The entire ecosystem of user-interacted webpages leveraging Cxense API remains at risk until definitive patches are applied.

REFERENCES

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