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Detect and block script-based attacks in the user's browser

Script-based attacks execute on the browser runtime of visitors without touching servers or backend infrastructure. Deploying cside adds a visibility layer edge-only tools cannot provide.

PCI DSS compliance

Full coverage of 6.4.3 & 11.6.1. Automated inventory, written justifications, and tamper alerts on payment pages.

Magecart & web skimming

Behavioral detection catches card skimming, including attacks hidden in trusted first and third party scripts.

Privacy compliance

Identify misconfigured or malicious third-party scripts that exfiltrate data and violate GDPR or CCPA.

Looking to secure your site against malicious third-party scripts?

Book a personalized demo to see:

Why third-party scripts are a security risk for you and your visitors
How to achieve PCI DSS compliance and prevent data breaches
Device fingerprinting for chargeback fraud prevention
Privacy monitoring and GDPR compliance strategies

Trusted by enterprise security & compliance teams

8020CluelyDIY NetworkeviivoFleetGenesis KioskGFA WorldJomashopKikoffMeeting EvolutionOpenPlayMetricsPowerhouse DynamicsProfessional CreditSpecsSystems EastTixWazuhBoldBeryl 8020CluelyDIY NetworkeviivoFleetGenesis KioskGFA WorldJomashopKikoffMeeting EvolutionOpenPlayMetricsPowerhouse DynamicsProfessional CreditSpecsSystems EastTixWazuhBoldBeryl
G2 Rating
"A simple PCI DSS solution backed by outstanding support"

Frederick Boyle, Director of Engineering, Amilia

Scripts on your payment page

47 scripts monitored

Compliant
47Scripts
42Allowed
2Blocked
HostActivityStatus
js.stripe.com/v3/checkout.js
payment-SDK · 14 callsAllowed
static.hotjar.com/c/hotjar-5.js
analytics · 6 callsAllowed
cdn.tagmanager.io/gtm-loader.js
new host · unreviewedReview
checkout-metrics.xyz/pay.js
reads card inputAllowed

Website scripts leak data and break compliance

Modern websites load scripts from dozens of third-party vendors. Each runs with full privileges in the browser.

  • Any one of them can be compromised to skim card data and exfiltrate PII.
  • This vector is invisible to WAFs and server-side controls that don't see how code executes in the user browser.

Without cside

stripe.jspayment
hotjar.jsanalytics
gtm.jsmarketing
card-skim.jsskimmer
fbevents.jsmarketing

Card data exfiltrated

PCI violation · breach risk

With cside

stripe.jspayment
hotjar.jsanalytics
gtm.jsmarketing
card-skim.jsskimmer
fbevents.jsmarketing

Threat blocked before execution

PCI compliant · users protected

Complete visibility and protection

cside monitors every 1st, 3rd, and 4th party script in real time with 100% session visibility.

  • AI-powered engine analyzes script behavior.
  • Detect web skimming and script injections before damage occurs.
  • Maintain PCI DSS 4.0.1 requirements 6.4.3 and 11.6.1 compliance automatically.

What customers say

The detection capabilities we got with cside were unlike anything we saw in other products we tested in the past. We would definitely recommend the product for PCI and more.

Mark D, CEO

Verified review from G2

Great Tool for PCI compliance. cside's product was exactly what we were looking for at a fraction of the price that other competitors were offering.

Anonymous Reviewer, Software Developer

Verified review from Sourceforge

Powerful visibility and compliance for third-party scripts. The setup is quick, the dashboard is clear, and the alerts make it easy to catch issues before they become problems.

Jacob C, CEO

Verified review from G2

I liked the documentation, I liked that it worked out of the box, and I liked the free plan. Generous to get started.

Jasmin S, CTO

Verified review from Sourceforge

PCI Compliance Software — SourceForge Top Performer SourceForge 4.9/5 rating G2 4.8/5 rating

Stop script-based attacks at the browser runtime layer

Your WAF protects the server. cside protects your customers' browsers. Sophisticated script-based attacks now execute on the browser runtime of visitors without touching servers or backend infrastructure. Deploying cside adds a visibility layer edge-only tools cannot provide, it hooks in before any other script, monitors 100% of sessions, and blocks malicious behavior at the source.

Coverage map

Edge & Origin Covered by WAF / CDN

CDN / edge cache

Static delivery, TLS termination

Edge

WAF

Rules, rate limit, bot mitigation

L7

Origin

Server + backend dependencies

Backend

Server-bound requests

Payloads, bots, rate-limit signals

Traffic
User Browser Layer Covered by cside

cside script

Loads first · monitors & blocks

Hook

Website code

First-party HTML + JS

1P

3rd-party scripts

Analytics, tags, SDKs

3P

Compromised script

Skims data · exfiltrates PII

Blocked
Covered by WAF / CDN

Server-bound requests, malicious payloads, bot traffic, and rate limits at the edge.

Covered by cside

Attacks that run in the visitor's browser: the true attack surface for skimming, formjacking, and script tampering.

How cside works

STEP 01

Script is loaded

cside's lightweight script tag is placed in the <head>. It initializes before any third-party script executes, monitoring every subsequent load.

STEP 02

Behavior is monitored

The AI engine analyzes what each script does, what data it accesses, where it is sent, known breaches, to find attack patterns in real time.

STEP 03

Threats are blocked

Malicious scripts are blocked or alerted. Every event is logged for PCI audit reports, forensic investigation, and compliance.

Multi-layered application security, delivered with cside.

Case study · PCI DSS compliance in under one day

ONLINE RETAILER
CHALLENGE

Payment pages relied on dozens of unmonitored third-party scripts. The security team needed a full script inventory and tamper alerts without rebuilding their stack.

SOLUTION

cside deployed as a single script tag in under a day. The PCI Shield dashboard instantly surfaced a full script inventory with AI-generated written justifications.

RESULTS

Full compliance achieved on first QSA submission. Weekly PDF reports generated automatically, days of manual effort saved with AI-written justifications.

Get started with cside

ABOUT CSIDE

cside is a web security platform specialized in browser runtime monitoring. Our platform protects hundreds of enterprises against e-skimming, Magecart attacks, data exfiltration, and compliance failures.

e-commerce Online retailers Payment processors FinTech Higher education SaaS

FAQ

Frequently Asked Questions

View all FAQs

cside provides full coverage for requirements 6.4.3 and 11.6.1. Requirement 6.4.3 mandates a complete inventory of all scripts on payment pages with written justifications for each. Requirement 11.6.1 requires tamper detection and alerting for unauthorized changes. cside automates both: it inventories every script, generates AI-written justifications, and monitors for tampering in real time.

Most teams are fully deployed in under 15 minutes. You add a single script tag to your pages. There are no infrastructure changes, no agents to install, and no code to rewrite. The script loads before any third-party code, so it starts monitoring immediately.

cside monitors the behavior of every script running in the browser at runtime. It tracks what data each script accesses, where it sends information, and whether it modifies sensitive page elements like payment forms. When a script deviates from expected behavior, for example exfiltrating card data to an external domain, cside flags or blocks it automatically.

Yes. cside is available as a SaaS listing on AWS Marketplace. Purchasing through the Marketplace lets you draw down existing AWS commit spend (EDP), consolidate billing, and simplify procurement. Deployment is identical. You get the same product, same dashboard, same support.

Yes. cside operates at the browser runtime layer, which is a different part of the stack from your WAF or CDN. Your WAF handles server-bound threats like malicious payloads and bot traffic. cside handles client-side threats like script tampering, data exfiltration, and formjacking that WAFs cannot see. The two are complementary.

Depending on your configuration, cside can block the script immediately, alert your team, or both. Every event is logged with full context including which script, what it did, and when it happened, so you have a complete audit trail for compliance reporting and forensic investigation.

Book a demo