Back to blog

Feroot vs cside

Monday, September 2nd, 2024

Updated July 17th, 2025

C

Carlo D'Agnolo

This article takes an honest look at the features of Feroot.

Since you’re on the cside website, we acknowledge our bias. That said, we’ve built our case honestly and based our analysis on publicly available information, industry information, objective technology analysis and our own or our customers' experiences.

If you want to verify their claims yourself, please navigate to their product page.

Criteria c/side Feroot Why It Matters What the Consequences Are
Approaches used Proxy JS-Based Detection
Real-time Protection Attacks can occur between scans or in the excluded data when sampled Delayed detection = active data breaches
Full Payload Analysis Ensures deep visibility into malicious behaviors within script code itself Threats go unnoticed unless the source is known on a threat feed
Dynamic Threat Detection Identifies attacks that change based on user, time, or location Missed detection of targeted attacks
DOM-Level Threat Detection Tracks changes to the DOM and observes how scripts behave during runtime Unable to identify sophisticated DOM-based attacks
100% Historical Tracking & Forensics Needed for incident response, auditing, and compliance Needed for incident response, auditing, and compliance
Bypass Protection Stops attackers from circumventing controls via DOM obfuscation or evasion Stealthy threats continue undetected
Certainty the Script Seen by User is Monitored Aligns analysis with what actually executes in the browser Gaps between what's reviewed and what's actually executed
AI-driven Script Analysis Detects novel or evolving threats through behavior modeling Reliance on manual updates, threat feeds or rules = slow and error-prone detection
QSA validated PCI dash The most reliable way to ensure a solution is PCI compliant is to conduct a thorough audit by an independent QSA Without QSA validation, you rely entirely on marketing claims, which could result in failing an audit
SOC 2 Type II Shows consistent operational security controls over time Lacks verified security control validation, making it a risky vendor
PCI specific UI An easy interface for quick script review and justification via one click or AI automation Mundane tasks and manual research on what all the scripts do, which takes hours or days

What is Feroot?

Feroot was founded to create a client-side security solution protecting dependencies, similar to cside back in 2017. They combine two approaches to deliver their security claims.

How Feroot works

Feroot’s offering is split into two products: “PageGuard” and “Inspector”.

Feroot PageGuard

Their PageGuard page reads:

“PageGuard deploys security permissions and policies to JavaScript-based web applications to continuously protect them from malicious client-side activities, malware, and third-party scripts.”

And:

“PageGuard overwrites certain main and core JavaScript code to protect your web application from client-side cyber threats.”

It’s clear they largely follow the same approach as most of our competitors. They use permissions and a form on an allow-list where you pre-approve which scripts are allowed to run on which pages.

There are a few problems with this approach.

If only the source of the script is checked using an allow-list, it has no clue which code get's served.

PageGuard would not have caught the biggest client-side attack of 2024, the Polyfill attack. Here a domain changed ownership and suddenly the script code changed. If only the source of the script is checked using an allow-list, it has no clue which code get's served. Solely relying on this is not safe.

Feroot Inspector

Their “Inspector”, deploys synthetic users disguised as honeypot customers, to simulate real user behavior. Inspector’s synthetic users are able to complete real user tasks and are able to identify malicious scripts and unauthorized actions on JavaScript web assets. This is a somewhat similar approach to Reflectiz.

This is effectively a crawler that does periodic checks on pages. A crawler can easily be avoided by only serving malicious scripts to residential IP adressess. Based on various parameters, like different user agents, different client-side scripts are served.

A crawler on its own can not meet PCI DSS requirements since one of the requirements is implementing 'a mechanism to prevent unauthorized scripts'.

How cside goes further

cside primarily offers a hybrid proxy approach which sits in between the user session and the 3rd party service. It analyzes the served dependencies code in real-time before serving it to the user.

This allows us to not only spot advanced highly targeted attacks and alert on them, cside also makes it possible to block attacks before they touch the user's browser. It also checks the box for multiple compliance frameworks, including PCI DSS 4.0.1. We even provide deep forensics, including if an attacker bypasses our detections. Allowing you to more tightly scope the size of the incident us to make our detection capabilities better every day. No other vendor has this capability.

We believe this is the most secure way to monitor and protect your dependencies across your entire website. We've spent years in the client-side security space before we started cside, we've seen it all, this is the only way you can actually spot an attack.

Sign up or book a demo to get started.

FAQ

Q: How does cside's hybrid proxy differ from Feroot's JavaScript agent approach?

A: The fundamental difference is timing of protection. Feroot deploys JavaScript agents in browsers that monitor for malicious behavior after scripts have already loaded and begun executing. cside's hybrid proxy intercepts and analyzes every script before it reaches browsers, blocking malicious content at the network level. We prevent attacks from happening, while Feroot detects them after they've already been delivered to users.

Q: Can attackers bypass cside's protection like they can with Feroot's browser-based agents?

A: No, because cside's core analysis happens on our proxy, completely invisible to attackers.  Feroot's JavaScript monitoring agents run in the browser where sophisticated attackers can detect, analyze, and potentially disable them. Attackers can craft code specifically designed to avoid triggering the behavioral monitoring. cside's proxy protection occurs server-side before content reaches browsers, making our security mechanisms completely invisible and impossible for attackers to study or circumvent.

Q: What forensic evidence does cside provide compared to Feroot's behavioral monitoring?

A: Feroot provides behavioral alerts and monitoring data when suspicious activity is detected, but cside captures and preserves the exact malicious code that was blocked. This gives you complete forensic evidence showing precisely what the attack looked like and what data it was designed to steal. Auditors get immutable proof of the actual attack code rather than just behavioral observations that may not capture the full threat.

Q: How do regulatory compliance capabilities compare between cside and Feroot?

A: cside provides comprehensive PCI DSS compliance with immutable payload archives and detailed audit trails covering both requirements 6.4.3 and 11.6.1. Feroot's behavioral monitoring approach provides detection logs but lacks the forensic-grade evidence and historical tracking that regulators increasingly require. Our approach creates the complete documentation that compliance officers need for thorough regulatory reporting.

Q: Why is cside's prevention approach better than Feroot's detection approach?

A: Prevention stops attacks before any damage occurs, while detection only alerts you after malicious scripts have already executed in users' browsers. With Feroot's approach, sensitive data can be stolen in milliseconds before the monitoring system detects the attack. cside's proxy ensures malicious scripts never get the chance to interact with user data because they're blocked before reaching browsers entirely.

C

More About Carlo D'Agnolo

I work on Marketing at c/side.