Inline Style Exfiltration: leaking data with chained CSS conditionals
Summary
Researchers have discovered a novel method for exfiltrating data using chained CSS conditional statements, bypassing previous limitations of CSS injection attacks. This technique allows for the leakage of attribute data directly through style attributes, even without the need for selectors or stylesheet imports.
IFF Assessment
This new attack vector presents a novel way for attackers to exfiltrate data, posing a new threat to web application security.
Severity
The technique allows for data exfiltration through CSS injection, which can be achieved remotely and has a significant impact on confidentiality. The attack vector is network-based and requires user interaction (visiting a malicious page), but the lack of authentication and the ease of exploitation contribute to a high score.
Defender Context
This research highlights a sophisticated data exfiltration technique leveraging CSS injection, emphasizing the need for robust input validation and sanitization on web applications. Defenders should be aware of this potential attack vector and ensure their WAFs and application logic can detect and prevent such chained CSS conditional exploits.