evilreplay for Modern Web Security Assessment

Bridging the gap between identifying a flaw and demonstrating its real-world risk can be challenging. The open-source project evilreplay provides a powerful, specialized utility that helps security practitioners effectively assess and report one of the most common web application threats: Cross-Site Scripting (XSS).

What is evilreplay?

At its core, evilreplay is a weaponized adaptation of the legitimate, enterprise-grade session replay software OpenReplay. While standard session replay tools are used by developers to debug applications by recording user interactions, evilreplay repurposes this technology for offensive security.

Its primary function is to provide a seamless remote browser session control capability. This means that once a target system is successfully compromised with an XSS vulnerability, a penetration tester can effectively “take over” the victim’s browser session, demonstrating the full extent of the security breach without the victim’s knowledge.evilreplay is not a standalone attack tool; it is a payload designed to be delivered via an existing Cross-Site Scripting (XSS) vulnerability.XSS occurs when an attacker can inject malicious client-side code (usually JavaScript) into a web page viewed by other users.

When the victim’s browser executes this injected script, the attack begins.

1. Payload Injection: The attacker injects the evilreplay JavaScript payload into the vulnerable web application.
2. Session Hijacking/Monitoring: Once the victim loads the compromised page, the payload executes. It establishes a covert connection to a server controlled by the attacker and begins recording and transmitting nearly every action the victim performs.
3. Remote Control: Critically, the attacker gains a real-time, interactive user interface (UI) to control the victim’s browser remotely. The security professional can simulate actions like clicking buttons, typing in forms, and navigating to new pages—all through the victim’s authenticated session.

In summary, evilreplay transforms a theoretical XSS finding into a high-impact, actionable demonstration, making it a valuable instrument for both learning and professional security assessment.evilreplay GitHub Repository. EgeBalci. Seamless remote browser session control. https://github.com/EgeBalci/evilreplay