Skip to main content
Simon Wijckmans
Founder & CEO

Simon Wijckmans

Founder and CEO of cside. Building better security against client-side executed attacks, and making solutions more accessible to smaller businesses. Web security is not an enterprise only problem.

Articles by Simon Wijckmans

The Snowball Effect: How Mini Shai-Hulud Turns npm into a Worm Distribution Network

Mini Shai-Hulud turned npm packages into a credential-theft loop. Here is how the AntV wave spread and what teams should monitor next.

Simon WijckmansSimon Wijckmans
May 19, 2026

Why CAPTCHAs Are No Longer Reliable Bot Defense

CAPTCHAs are no longer a reliable primary bot defense. Learn why visible challenges fail and how resource-wasting defenses raise attacker cost.

Simon WijckmansSimon Wijckmans
May 19, 2026

Funnull Sanctioned: What the Polyfill[.]io Attack Exposed About Infrastructure Laundering

OFAC's Funnull sanctions show why the Polyfill attack was part of a larger infrastructure laundering and browser supply-chain risk.

Simon WijckmansSimon Wijckmans
May 18, 2026

On-Device Inference Is Coming for Your Security Stack: For Better and Worse

On-device AI can protect sensitive data and power endpoint defense, but it also creates new prompt injection, telemetry, and browser attack paths.

Simon WijckmansSimon Wijckmans
May 18, 2026

cside Named SourceForge Spring 2026 Top Performer for Client-Side Security

cside was named a SourceForge Spring 2026 Top Performer, reflecting user trust in client-side security, PCI evidence, and support.

Simon WijckmansSimon Wijckmans
May 13, 2026

cside Co-Chairs W3C Anti-Fraud Browser Security

Simon Wijckmans now co-chairs W3C AFCG as cside helps shape privacy-preserving browser signals for AI-era fraud.

Simon WijckmansSimon Wijckmans
May 12, 2026

How OpenClaw Agents Bypass Bot Detection (And How to Stop Them)

OpenClaw agents paired with stealth browser tooling can bypass legacy bot detection. Learn how agentic fraud works and how browser fingerprinting helps stop it.

Simon WijckmansSimon Wijckmans
Apr 28, 2026

How Advanced Location Data Prevents Account Takeover and Detects Unsafe AI-Agent Token Reuse

How advanced location data helps security teams detect impossible travel, stolen-session reuse, and unsafe AI-agent activity before account takeover turns into fraud or data loss.

Simon WijckmansSimon Wijckmans
Apr 15, 2026

How Compromised Third-Party Scripts Can Prompt-Inject AI Agents

Third-party scripts already adapt website behavior by browser characteristics. That same flexibility can be abused to detect AI agents and inject misleading instructions or altered content.

Simon WijckmansSimon Wijckmans
Apr 13, 2026

DarkSword: pure JavaScript exploit chain weaponizes legitimate websites

DarkSword is a full-chain iOS exploit delivered via watering-hole compromises of legitimate websites. It runs entirely in JavaScript, evades binary mitigations, and drops JavaScript-based backdoors that exfiltrate sensitive data.

Simon WijckmansSimon Wijckmans
Mar 20, 2026

AppsFlyer Web SDK supply-chain compromise - polymorphic crypto stealer

A registrar-level DNS hijack of appsflyer.com served a polymorphic crypto-stealing payload through the AppsFlyer Web SDK, affecting thousands of sites and some Node.js server environments. This post summarizes telemetry, forensic indicators, IOCs, detection guidance, and remediation steps.

Simon WijckmansSimon Wijckmans
Mar 18, 2026

OpenClaw Scanner for Third-Party Scripts

A free, open-source scanner that inventories third-party scripts, detects fingerprinting, audits security headers and cookies, and flags PCI DSS exposure on payment pages. Run a quick 30-second audit to reveal what code executes in your users' browsers.

Simon WijckmansSimon Wijckmans
Mar 18, 2026

Inside Coruna - Web Script IOS Exploit

Your website could have been used to distribute this iOS exploit kit and you wouldn't have known. A full technical breakdown of Coruna: five exploit chains, 23 CVEs, and the delivery infrastructure that makes every website a potential attack vector.

Simon WijckmansSimon Wijckmans
Mar 8, 2026

"Microsoft Clairty" Isn't Microsoft Clarity: Deobfuscating a Typosquatted Ad Fraud Script

Cside observed a new malicious client-side injection originating from a malicious browser extension impersonating Microsoft Clarity and overwriting referral tokens to redirect referral revenue to a malicious actor.

Simon WijckmansSimon Wijckmans
Mar 3, 2026

Best practices for securing third party scripts on web pages

Third-party scripts can expose sensitive data in your users’ browsers. Learn best practices to secure client-side code and reduce breach risk.

Simon WijckmansSimon Wijckmans
Jan 21, 2026

Best client-side security tools for web applications

Web Applications leverage client-side scripts. A multi layer monitoring approach is the best way to detect suspicious activity on those scripts.

Simon WijckmansSimon Wijckmans
Jan 15, 2026

How to detect VPN traffic on a website

U.S. and U.K. age-verification laws require companies to prevent minors from accessing restricted content, including circumvention controls against VPNs.

Simon WijckmansSimon Wijckmans
Jan 14, 2026

2026 Web Security Predictions from cside's CEO

2026 will look different from past years. We'll be watching for: deepfake powered phishing, LLM hallucinated security recommendations, and AI agent attackers.

Simon WijckmansSimon Wijckmans
Jan 8, 2026

The Differences In Client-side Security Solutions

When a user visits a site, a web server directs the browser to fetch contents. Some from servers the website owner manages, sometimes from 3rd parties. Client-side security solutions aim to give control back to the website owner, because they are responsible for the tools on their site

Simon WijckmansSimon Wijckmans
Jan 6, 2026

Best client-side security for eCommerce?

eCommerce sites are heavy consumers of client-side tracking tags which creates a significant risk for malicious exfiltration of sensitive data but also legitimate tags collecting more data than is necessary to sell to data brokers. The cside solution solves these concerns with ease.

Simon WijckmansSimon Wijckmans
Dec 26, 2025

Best client-side security for Financial Institutions?

Nation-state targets like Financial Institutions need to partner with vendors that understand limitations and work to get as close to full coverage as is possible. Read why many choose cside's multi-layer model.

Simon WijckmansSimon Wijckmans
Dec 24, 2025

The British Airways Attack of 2018 - The Deeper Story

The 2018 British Airways attack affected 429,612 individuals. See why cside bought the attacker domain to turn it into a lesson on modern web security.

Simon WijckmansSimon Wijckmans
Dec 15, 2025

How cside brought AI to Client-Side Security

In 2024, cside launched the first client-side security solution with integrated AI for JavaScript security analysis and compliance automation.

Simon WijckmansSimon Wijckmans
Dec 14, 2025

Addressing Incorrect Claims Made by Reflectiz About cside

Learn why Reflectiz’s scanner-based claims about cside are incorrect and how cside’s real-time client-side security provides deeper protection, full payload forensics, and PCI DSS 4.0.1 compliance.

Simon WijckmansSimon Wijckmans
Dec 8, 2025

Script Integrity Management for e-commerce Brands (SRI, Dynamic Scripts)

Deep dive into script integrity vs Subresource Integrity vs behavioral monitoring for PCI DSS 6.4.3, 11.6.1, ISO 27001, and HIPAA compliance.

Simon WijckmansSimon Wijckmans
Nov 26, 2025

The Cloudflare incident: How cside minimized customer impact

On November 18th, Cloudflare had an incident that impacted thousands of customers. This blog explores how we limited impact to our own customers.

Simon WijckmansSimon Wijckmans
Nov 21, 2025

How WebView mobile apps are dangerous for banking

Banking "apps" that run on browser environments expose credentials without teams realizing it. This article explores examples of WebView mobile app attacks.

Simon WijckmansSimon Wijckmans
Nov 21, 2025

Fail Open Architectures: the importance of being ready for a bad day.

Customers diligently ask: “what happens if cside goes down?” or “will it add latency?”. This is how our fail-open architecture is prepared for a bad day.

Simon WijckmansSimon Wijckmans
Nov 14, 2025

How to Bypass JavaScript Agents, CSP, and Crawlers (Client-Side Security Testing)

Most client-side compliance tools can be easily bypassed. We show you how to test weaknesses in CSP, crawler, and JS agents + safer alternatives.

Simon WijckmansSimon Wijckmans
Oct 21, 2025

What is Client-Side Security?

Browsers are powerful feature rich environments. More applications also are effectively browsers behind the scenes. This is great for building an application, but bad actors also use the client as an attack surface.

Simon WijckmansSimon Wijckmans
Oct 2, 2025

Mockito docs hijacked

Some attacks are stupidly low tech. Mockito, a popular open source package contained a malicious link in their Github Docs.

Simon WijckmansSimon Wijckmans
Sep 30, 2025

Vibe Coding Security Risks: Client-Side Exposures in AI Platforms (Lovable, Copilot, Cursor & more)

Understand the common vulnerabilities in code made with AI coding platforms like Lovable, Copilot, Cursor, + Replit. See how to fix them before you ship them.

Simon WijckmansSimon Wijckmans
Sep 30, 2025

What QSAs Should Look For When Assessing PCI 6.4.3 and 11.6.1

We put together a shorthand checklist, red flags to look for, and the compliance differences between CSP, Crawlers, and Client-side scripts.

Simon WijckmansSimon Wijckmans
Sep 9, 2025

Client-Side Attack Report Q2 2025

cside’s research uncovered over 72,000 compromised websites, revealing how attackers are relying on JavaScript-based delivery mechanisms, third-party supply chain vulnerabilities, and deceptive browser based social engineering tactics such as fake browser updates.

Simon WijckmansSimon Wijckmans
Jul 30, 2025

The PII Blind Spot in Web Security

But PII moves through the frontend, where controls are weaker and visibility is often limited.

Simon WijckmansSimon Wijckmans
Jul 30, 2025

UK Internet Age Verification System explained for cyber security

The goal of the UK Internet Age Verification System is to protect children browsing on the internet. But these checks come with new cybersecurity risks and privacy concerns.

Simon WijckmansSimon Wijckmans
Jul 29, 2025

cside at PCI SSC 2025 North America Community Meeting

We are in town for the PCI SSC 2025 North America Community Meeting, September 16th to 18th.

Simon WijckmansSimon Wijckmans
Jul 24, 2025

How Chrome extensions can remove security headers

Many browsers actively update extensions without specific approval or opt-in. This means that an extension today can behave wildly differently tomorrow, and you will not be made aware of it.

Simon WijckmansSimon Wijckmans
Jul 21, 2025

What's the leading technology to prevent credit card skimming?

Visa’s Spring 2025 Biannual Threats Report identifies digital skimming as one of the “most prolific and consistent threats” in the payments ecosystem.

Simon WijckmansSimon Wijckmans
Jul 21, 2025

cside at BlackHat USA 2025

cside is exhibiting at BlackHat USA 2025.

Simon WijckmansSimon Wijckmans
Jul 9, 2025

Why crawlers can't help with PCI compliance (alone)

Crawlers act like a user but are very clearly not a real human user. If a malicious script would get injected because of a user interaction, the crawler will not see the malicious script unless it makes that user interaction

Simon WijckmansSimon Wijckmans
Jul 3, 2025

PCI Compliance 4.0.1: A Practical Implementation Guide Webinar

We partnered up with VikingCloud, the largest global PCI compliance QSA and security firm on 2 webinars giving you the full context and info to implement PCI DS 4.0.1. With a special focus on requirements 6.4.3 & 11.6.1.

Simon WijckmansSimon Wijckmans
Jun 26, 2025

Why We’re Called cside

We named ourselves after the part of the web that no one else was protecting: the client-side.

Simon WijckmansSimon Wijckmans
Jun 25, 2025

Malicious North Korean actors attempt to infiltrate technology companies

Catching fraudulent job applicants.

Simon WijckmansSimon Wijckmans
May 1, 2025

Client-Side Attack Recap – Q1 2025

cside’s research uncovered nearly 300,000 compromised websites in Q1 of 2025.

Simon WijckmansSimon Wijckmans
Apr 30, 2025

VikingCloud approves cside for PCI DSS requirement 6.4.3 and 11.6.1

Cside has partnered with VikingCloud to perform a deep technical assessment of the security solutions we offer under the enterprise plan under the scope of PCI compliance. Offering full peace of mind that with a proper implementation of our products requirements 6.4.3 and 11.6.1 are met.

Simon WijckmansSimon Wijckmans
Apr 24, 2025

Is there a "free" method to comply with PCI DSS 6.4.3 and 11.6.1?

The short answer: Without an off the shelf solution, you'd have to build a DIY monitoring tool that would cos significantly more in wages than a prebuilt solution's vendor costs.

Simon WijckmansSimon Wijckmans
Apr 23, 2025

Do you need PCI SSF or PCI DSS? Here’s the difference

PCI SSF is for the software, and PCI DSS is for everything else. Let's dive in.

Simon WijckmansSimon Wijckmans
Apr 22, 2025

Can you use Adyen for PCI DSS?

Yes, BUT depending on which on the integration, your business is still responsible for ensuring compliance with the Payment Card Industry Data Security Standard (PCI DSS).

Simon WijckmansSimon Wijckmans
Mar 21, 2025

Can you use PayPal (Braintree) for PCI DSS?

Yes, BUT depending on which on the integration, your business is still responsible for ensuring compliance with the Payment Card Industry Data Security Standard (PCI DSS).

Simon WijckmansSimon Wijckmans
Mar 21, 2025

Can you use Stripe for PCI DSS?

Yes, BUT depending on which on the integration, your business is still responsible for ensuring compliance with the Payment Card Industry Data Security Standard (PCI DSS).

Simon WijckmansSimon Wijckmans
Mar 21, 2025

BSidesSF and RSAC Event

When cside is exhibiting, the afterparties are in town! Organized by us, Socket, Arcjet and Incident! Find our booth at BSidesSF (follow the laser), and booth 2438 at RSAC. Register for the 30th of April Book a meeting Join us for the ultimate cybersecurity networking experience at the Rooftop of our investor Uncork Capital in San Francisco! Organized by cside, Socket, Arcjet, and Incident, these exclusive events bring together 250+ techies, cybersecurity professionals, and BS

Simon WijckmansSimon Wijckmans
Mar 13, 2025

How to be a PCI DSS SAQ A company (6.4.3 and 11.6.1)

One sentence sparks debate. Because sites load scripts dynamically, a script from any page can persist into checkout, potentially interfering with payments. Third-party scripts, even if unrelated or on pages loaded before the payment pages, can introduce vulnerabilities.

Simon WijckmansSimon Wijckmans
Mar 7, 2025

Bybit Attack: $1.5B stolen through malicious JavaScript

The attackers injected malicious JavaScript into the website interface where Bybit’s employees normally approve transactions. This malicious code was hidden in such a way that everything looked normal on the screen—but behind the scenes, it changed important details.

Simon WijckmansSimon Wijckmans
Feb 27, 2025

cside is now SOC2 compliant

We’re proud to announce our SOC2 type 2 audit has passed and we passed with the highest degree of approval.

Simon WijckmansSimon Wijckmans
Feb 5, 2025

Demystifying the January 2025 updates to PCI DSS SAQ A

A full detailed explanation, chart and guide to the changes regarding PCI DSS 4.0.1 - 6.4.3 and 11.6.1

Simon WijckmansSimon Wijckmans
Feb 2, 2025

Affiliate tracking and its cyber security risks

Malicious actors often exploit tracking pixels to inject harmful scripts on otherwise normal websites.

Simon WijckmansSimon Wijckmans
Jan 20, 2025

Why Content Security Policy doesn't work

Content Security Policy (CSP) is a security feature provided by web browsers that a website owner can use to define a set of rules that control which resources (e.g., scripts, styles, images) can be loaded and executed by the browser. We call this the client-side, which is at the very end of the web supply chain. When properly configured, it helps prevent a wide range of attacks. But those first three words make all the difference. It can help prevent: Cross-Site Scripting (XSS): By restricti

Simon WijckmansSimon Wijckmans
Jan 7, 2025

Ad marketplaces security and compliance risks

For businesses monetizing through ad marketplace models, the less traditional 3rd-party advertising networks, analytics platforms, and marketing scripts are indispensable. They’re needed to drive revenue by boosting engagement and tracking user behavior.

Simon WijckmansSimon Wijckmans
Dec 23, 2024

A new Progressive Web App danger very few know about

The rise in adoption with PWAs comes an increase in client-side security risks. And the industry? It’s barely talking about it.

Simon WijckmansSimon Wijckmans
Dec 20, 2024

The Polyfill[.]io attack - More than just a redirect attack

When we and news outlets reported the Polyfill attack, the reactions were surprisingly mild. This may have been due to the visible result: a simple redirect to obscure websites. But, as we outlined in our post-mortem, the potential consequences are far more severe: “Here the bad actor opted to only redirect users to adult and betting websites, however much worse could have happened. Listening in on keystrokes in a small percentage of sessions based on geolocation and time of the day, injecti

Simon WijckmansSimon Wijckmans
Dec 6, 2024

How web extensions can hurt your site (INFIRC[.]com and INFIRD[.]com)

The domain infirc[.]com and infird[.]com have caused quite the stir recently, and highlighted the dangers of infected or malicious web exten

Simon WijckmansSimon Wijckmans
Oct 18, 2024

The Internet Archive Hack: How JavaScript fits in the picture

The Internet Archive, also known as The Wayback Machine, experienced a security breach yesterday. This was not the first time it had been ta

Simon WijckmansSimon Wijckmans
Oct 18, 2024

The biggest Magecart attacks in history (so far)

Where the term “Magecart” comes from from Magecart attacks are a type of cyberattack where hackers inject malicious JavaScript code, often r

Simon WijckmansSimon Wijckmans
Oct 17, 2024

New TTPs in Stealing PII and Financial Information from Magento Websites

At cside, we actively monitor client-side supply chain attacks, with a focus on the evolving tactics, techniques, and procedures (TTPs) used by threat actors. One of the most common attacks we've observed over the past few months is the targeting of eCommerce websites built on the Magento framework. In particular, we've been closely following the Cosmic Sting attack (CVE-2024-34102), which has been widely reported, including by Sansec (https://sansec.io/research/cosmicsting). Recent TTP Obser

Simon WijckmansSimon Wijckmans
Oct 14, 2024

Why do websites need 3rd party scripts?

When developing a website, you’ll often include libraries to help speed up the development process, and avoid reinventing the wheel. However

Simon WijckmansSimon Wijckmans
Oct 10, 2024

cside joins the PCI Security Standards Council as an Associate Participating Organization

We’re proud to announce that we've joined the Payment Card Industry Security Standards Council (PCI SSC) as an Associate Participating Organization. The PCI SSC leads a global, cross-industry effort to enhance payment security by establishing flexible, industry-driven data security standards. Through collaboration with other industry leaders, the Council’s mission is to protect payment data from emerging threats and meet the evolving needs of the payment ecosystem. As an Associate Participatin

Simon WijckmansSimon Wijckmans
Oct 7, 2024

Carlsberg a target in Magento “CosmicSting” malware attack

The term “Magecart” refers to attacks on the Magento platform. Recently, another large campaign was found to target Magento sites again. Among these, Carlsberg was one of the compromised websites. The pattern of these attacks is almost always the same. A single line of JavaScript loads content from a remote website. In other words, a 3rd party script. That code is then heavily obfuscated to delay detection even more. In this case, the payment process was quietly changed. A fake payment method

Simon WijckmansSimon Wijckmans
Oct 4, 2024

cside joins the W3C

We’re incredibly proud to announce we have joined the W3C Web Application Security Working Group. The mission of the Web Application Security Working Group is to develop mechanisms and best practices to improve the security of web applications. Our whole team has been involved in cybersecurity for years. Through cside, we now aim to raise awareness and set higher standards for client-side security. By joining forces, we are one step closer to achieving both of our goals. We want to publicly t

Simon WijckmansSimon Wijckmans
Oct 4, 2024

Threat feeds fail to detect attack for +2 years

On this website, we can see it’s been active since August of 2022. We've notified this, and other websites of this attack.

Simon WijckmansSimon Wijckmans
Oct 2, 2024

Why do developers obfuscate JavaScript?

As a client-side security company protecting JavaScript, we see a lot of obfuscated scripts. When you use our tool, you can actually see the deobfuscated version of the scripts to see what it is doing. Deobfuscation has been around for a while, but why is code obfuscated in the first place? JavaScript obfuscation came around to protect the source code of web applications from being easily understood, copied, or exploited by unauthorized users. Obfuscation as a concept predates JavaScript and e

Simon WijckmansSimon Wijckmans
Oct 1, 2024

ButterCMS unreported downtime and security concerns

ButterCMS is a popular tool used to manage content for blogs. Earlier this week, we noticed a potentially severe security incident which tri

Simon WijckmansSimon Wijckmans
Sep 23, 2024

Cside raises a $6m seed round

We’re incredibly proud to announce our seed round of $6m, just six months after raising our pre-seed of $1.7m. Led by Uncork Capital as the lead, with participation from Mantis and PrimeSet. We also welcome back Scribble VC and Roar Ventures who supported us in the pre-seed. Together with this news, we’ve opened up our free tier to all. You can now sign up and start using cside to monitor, secure, and optimize 3rd party scripts. We founded cside to put client-side security on the map. For t

Simon WijckmansSimon Wijckmans
Sep 16, 2024

Cside picked for TechCrunch Disrupt Startup Battlefield 2024

We’re incredibly proud to announce that we were selected for TechCrunch Disrupt Startup Battlefield in 2024. This year’s Startup Battlefield participants span artificial intelligence (AI), software as a service (SaaS), fintech, security, sustainability, space exploration, and more. Out of thousands of startups, just 200 make the cut, and we are absolutely thrilled to be among this select group. We can not wait to share our product with the world, Oct. 28 - Wed, Oct. 30 at Moscone West in San F

Simon WijckmansSimon Wijckmans
Sep 5, 2024

How to speed up JavaScript

Conversion rates are correlated with site loading speeds. But e-commerce sites have a ton of JavaScript which slows things down... the solution is here.

Simon WijckmansSimon Wijckmans
Sep 2, 2024

What are digital skimmers?

Recently, we read of a new significant cyberattack campaign that targeted hundreds of online stores, exploiting vulnerabilities in third-party scripts and plugins. This is a perfect example of a ‘digital skimmer’. Digital skimmers are snippets of code maliciously injected into legitimate websites. They target personal and credit card information. This problem is on the rise and is part of the reason cside was created. Our proxy is able to detect this malicious code and prevent it from affecti

Simon WijckmansSimon Wijckmans
Aug 29, 2024

Why browsers are becoming increasingly more dangerous

Technologies like WebAssembly (WASM), WebGPU, and IndexedDB have transformed what browsers can achieve. This evolution has expanded the func

Simon WijckmansSimon Wijckmans
Aug 23, 2024

The true cost of a cyber attack

Calculating the true cost of a cyber attack is difficult. None are the same. Yet we report on this in as much detail as possible to accurately represent the full picture of when this happens to your business.

Simon WijckmansSimon Wijckmans
Aug 12, 2024

Is Tuaw a scam in the making?

When we saw the new Fireship video yesterday, we were immediately reminded of the recent Polyfill attack. Our first article was picked up an

Simon WijckmansSimon Wijckmans
Aug 2, 2024

The Copay event-stream attack illustrates dependency risks

The JavaScript ecosystem experienced a significant shock with a sophisticated attack on Copay, a popular cryptocurrency wallet provider, in November 2018. Known as the event-stream attack, this incident highlighted the critical vulnerabilities associated with relying on third-party dependencies in software development. Copay is now known as Bitpay Wallet. Understanding the attack Event-stream, a popular npm package, was widely utilized by numerous projects for efficiently managing streams

Simon WijckmansSimon Wijckmans
Jul 29, 2024

The Segway cyber attack explained

In January 2022, the Segway web store suffered a web supply chain attack - also often referred to as a Magecart attack. In these types of attacks, malicious JavaScript code is added that loads from the client-side, known as third-party scripts. Many common tools are third-party scripts. Things like analytics, captchas and more. But this avenue can also be used for malicious reasons, as was the case here. In this attack on Segway, their store is set up on Magento. The attackers targeted vulnera

Simon WijckmansSimon Wijckmans
Jul 25, 2024

Don't deploy scripts site-wide

Third-party scripts are often deployed site-wide, typically injected in the head tags in web frameworks like Next.js via the ’_document.js’ file. This widespread implementation, while convenient for developers and often recommended by onboarding guides, means these scripts run across the entire site. This is simpler to implement, but it also introduces security risks and performance issues that are often overlooked. The recent Kaiser Permanente data leak shows the dangers of having poorly manag

Simon WijckmansSimon Wijckmans
Jul 22, 2024

What is an attack vector and what are hidden ones

An attack vector in cybersecurity is the way an attacker takes advantage of security weaknesses. Some are more obscure than others. One that’s been our focus is third-party JavaScript. Since these scripts are installed by the website owner yet executed in the visitors' browsers, they're in a unique position. If something malicious occurs within these scripts, neither party is aware. The visitor is affected, and the website owner becomes liable. We’ve seen this too many times, for example, the

Simon WijckmansSimon Wijckmans
Jul 15, 2024

How expired domains lead to cyber attacks

How Expired Domains Lead to Cybersecurity Attacks In 2018, British Airways was attacked through the exploitation of a third-party JavaScript

Simon WijckmansSimon Wijckmans
Jul 8, 2024

The Polyfill attack explained

A tampered JavaScript file injected by the polyfill[.]io domain redirected a percentage of users to adult and betting websites based on their User-Agent. A Japanese X user “piyokango” was likely the first to report his attack on the 24th of June.

Simon WijckmansSimon Wijckmans
Jul 3, 2024

What is the browser supply chain?

Cside is a cybersecurity product that lives in the browser supply chain space. We and other vendors operating here like to talk about that supply chain. But, what exactly do we mean by it? The browser supply chain is the combination of components and processes that come together to render web pages, execute scripts, and ensure smooth functionality. This supply chain includes everything from the initial request for a webpage to the final rendering of that page in a user's browser. As well as dyn

Simon WijckmansSimon Wijckmans
Jul 2, 2024

More than 490k websites targeted in web supply chain attack

The cdn.polyfill.io domain is currently being used in a web supply chain attack. It used to host a service for adding JavaScript polyfills t

Simon WijckmansSimon Wijckmans
Jun 25, 2024

The BrowseAloud Supply-Chain Attack: A Case Study in Cryptojacking

This attack affected more than 4,000 websites, including government and educational sites, exposing thousands of users to cryptojacking without their knowledge.

Simon WijckmansSimon Wijckmans
Jun 10, 2024

Supply Chain Risk Doesn’t End At NPM

By only checking NPM (or another registry), you’re not protected from attacks through third-party scripts.

Simon WijckmansSimon Wijckmans
May 30, 2024

Ticketmaster Data Breach Déjà Vu: What You Need to Know

Yesterday on May 29, 2024, news broke of an alleged data breach involving Ticketmaster, a prominent ticket sales and distribution company. Ticketmaster has confirmed unauthorized activity within a third-party cloud database environment, claiming to have exposed the personal information of over 500 million customers. This breach includes sensitive data such as emails, phone numbers, addresses, and financial details. ShinyHunters, a notorious attacker, reposted the breach . According to reports,

Simon WijckmansSimon Wijckmans
May 30, 2024

Kaiser Permanente Data Leak: A Case of Miscommunication and Inadequate Disclosure

On April 29th, healthcare giant Kaiser Permanente disclosed a data leak impacting 13.4 million current and former insurance members. The incident was rooted in improperly managed 3rd party scripts. The Incident Kaiser Permanente used tracking codes to monitor how its members navigated through its website and mobile applications. Some of these pages contained sensitive healthcare data, leading to the 3rd party scripts inadvertently transmitted information to third-party vendors they weren’t

Simon WijckmansSimon Wijckmans
May 25, 2024

Threat Feeds In The AI Era

The idea behind threat feeds is valid. But, we’d argue it’s past its prime at this point. And with where technology is today, there are better options. Threat feeds are (often) a list of community-sourced security information. When someone notices a vulnerability, they’ll put out a notice to the thread feed manually. It then gets picked up, and featured in the feed where security folk at their respective companies read it and check their own systems to see if they are prone to potential danger.

Simon WijckmansSimon Wijckmans
Apr 28, 2024

The 2021 cdnjs Vulnerability in Detail

Verifying that your 3rd party script sources are reputable is important. But that alone may not be enough. That’s what the world learned in 2021, when a massive vulnerability in Cloudlfare’s cdnjs was flagged. Here’s the rundown of what, and how, it happened. Cdnjs is one of the most commonly used JavaScript Content Delivery Networks (CDNs) of today. Over 12% of all websites on the internet inject at least one script through cdnjs. A researcher with the screen name ‘RyotaK’ shared a supply cha

Simon WijckmansSimon Wijckmans
Apr 28, 2024

The risk of only protecting your payment portals from 3rd party javascript attacks

PCI DSS 4.0 is here. By March 2025, it mandates that payment portals need to have a way to authorize each script on payment pages. Websites need to maintain an inventory of all scripts (on those payment portals at least) and ensure their integrity. You now need to detect and respond to unauthorized modifications on payment pages, including changes to HTTP headers and page contents. Organizations must check these configurations at least once every seven days or as determined by their risk analysi

Simon WijckmansSimon Wijckmans
Apr 15, 2024

PCI DSS 4.0.1 complete guide and steps

PCI DSS 4.0 complete guide and steps The Payment Card Industry Data Security Standard (PCI DSS) is a set of guidelines that ensures the safe

Simon WijckmansSimon Wijckmans
Mar 4, 2024
Book a demo