Securing the Browser’s Blind Spot
By Victoria Hargrove, CDM Reporter
What CSide Does
Most security stacks fortify servers, databases, and internal apps. CSide (Client-side Development, Inc. aka c/side) targets the place attackers increasingly exploit: the user’s browser. By inserting a lightweight control into site code, CSide creates a 24/7 client-side shield that detects and blocks malicious scripts such as formjacking and digital skimming before they siphon data.
PCI DSS Dashboard:
Context: Where users see the list of scripts running on their site, along with justification comments to comply with PCI DSS 4.0 requirements
Why It’s Innovative
Perimeters have shifted. Third-party scripts and supply-chain code execute inside browsers where traditional tools have little visibility. CSide analyzes those scripts in real time and pairs its telemetry with a locally hosted, custom-tuned LLM that summarizes payload behavior in plain English and continuously improves detections.
What Makes It Different
Many vendors monitor from the outside. CSide operates a proxy-based model that sits between the user and the JavaScript executed in the browser. Result: deeper inspection and stronger control than crawler-only approaches. Every script payload is inspected for risky behaviors like keystroke logging or unauthorized data exfiltration, and the dashboard surfaces a clear inventory plus human-readable summaries of what each script is doing.
The Problem and CSide’s Fix
- Risk: Payment pages and data-collection forms are prime targets for client-side attacks. Incidents like the 2018 British Airways web-skimming breach carried penalties exceeding €20M.
- Compliance pressure: PCI DSS 4.0 (coming into full force in 2025) tightens requirements around third-party JavaScript, including maintaining a detailed inventory of scripts on payment pages.
- Solution: CSide’s client-side intelligence platform monitors every third-party script in every session via its proxy. Teams in finance, eCommerce, and online retail gain effortless visibility, policy controls, and out-of-the-box reporting to meet PCI DSS 4.0 script-monitoring expectations.
Operations Dashboard:
Context: Session-by-session monitoring, risk classification, and remediation cues.
Voices From the Field (G2 Reviews)
- Joseph M., Software Engineer: “CSide tells me everything I need to know about a script, and proactively makes sure they are safe to show to the user. It’s really made me realize how big of a problem 3rd-party script security is.”
- Edgardo C., Developer: “I use so many third-party scripts… any of these could go rogue. CSide lets me know if dependencies suddenly change behavior or if something suspicious happens like a domain transfer.”
Founder’s Take
Simon, Founder: “Cybercriminals have shifted into the browser, and most traditional web security tools haven’t kept up.”
If your team needs real client-side visibility and a practical path to PCI DSS 4.0 readiness, CSide is a focused entrant worth a close look.
Contact: Juan Combariza, [email protected] and learn more at: https://cside.dev/
About the Author
Victoria Hargrove is an award-winning independent Reporter for Cyber Defense Magazine and a 2024 graduate of George Mason University, where she earned a Bachelor of Science in Management Information Systems. Her academic journey included a comprehensive focus on cybersecurity, with coursework in networks and security, information security and assurance, programming, and networking, among other areas. Building on this foundation, she is attending Old Dominion University where she is earning her Master’s degree in Cybersecurity which will be completed in Spring 2026. Her experience in these areas allows her to apply her theoretical knowledge to real-world challenges, positioning her as a skilled professional in the cybersecurity domain. In addition to her academic and professional goals, Victoria is deeply committed to community engagement, particularly in supporting underrepresented groups in technology. She believes that education is a powerful tool for creating opportunities, and she is passionate about mentoring and outreach. In her own words: “Education has opened doors for me, and I aspire to do the same for others. Mentorship and outreach for underrepresented groups in technology is something I’m passionate about. I know true success is measured by how much we can lift others as we climb.” As she continues to advance her knowledge and expertise, Victoria remains eager to engage in research and tackle the evolving challenges of the Cybersecurity landscape. Victoria can be reached online at [email protected].
