Bug Bounty ShortsExploiting DOM Clobbering to Enable DOM-Based XSS
This article discusses a DOM-based Cross-Site Scripting (XSS) vulnerability, exploited through manipulation of JavaScript variables. The root cause was the application's failure to sanitize user inputs when setting object properties, leading to data injection into sensitive contexts. By using DOM clobbering (overwriting existing JavaScript variables with malicious payloads), the researcher was able to insert arbitrary scripts within the vulnerable domain's context. This attack vector allowed for injecting and executing XSS payloads without relying on reflected or stored attacks. The technical details demonstrate that sensitive information could be leaked or modified by an attacker through this flaw, leading to privacy breaches and potential account takeovers. The researcher reported the vulnerability, received a bounty reward, and encouraged developers to sanitize user inputs when setting object properties and apply Content Security Policy (CSP) with appropriate directives. Key lesson: Always validate user inputs and be mindful of JavaScript variable assignments to prevent DOM-based XSS attacks. #BugBounty #WebSecurity #XSS #InputValidation #DOM
