Proposed Update to OWASP XSS Guidance: Differentiating the Impact and Spread of Reflected vs. Stored XSS Attacks

[FaridAmroun]

Hi

In the current OWASP guidelines, Reflected XSS and Stored XSS are described with a focus on their technical distinctions—namely, that Reflected XSS is a non-persistent form of attack that requires user interaction, while Stored XSS persists on the server and automatically affects every user accessing the affected page.

However, we suggest an update to include a nuanced understanding of how Reflected XSS can also achieve wide-reaching impact through the strategic use of social media, email, and other platforms, enabling it to spread quickly to large audiences. In practice, Reflected XSS can have a viral effect when shared across popular communication channels, potentially reaching a scale similar to Stored XSS attacks in terms of user impact.

To improve clarity, we propose:

Highlighting that Reflected XSS can achieve large-scale impact through link-sharing on social media and other widely used platforms, even if it requires user interaction.
Emphasizing that Stored XSS does not rely on user sharing for broad impact, as it is embedded directly in the application, affecting all users who visit the infected page.
This update could help developers and security practitioners understand that while Stored XSS and Reflected XSS differ in persistence, both can achieve widespread impact depending on the attack vector and sharing methods.

My best Regards
Farid