Professional Cross-Site Scripting (XSS) Testing Services

Applications Tested for XSS

Had XSS Vulnerabilities

Security Report Delivery

XSS Vulnerabilities Found

Web applications vulnerable to XSS

Security breaches involve XSS exploitation

Applications lack proper output encoding

Average XSS-related breach cost

⚡ Reflected XSS Testing

Reflected XSS testing examines non-persistent XSS vulnerabilities in URL parameters, form inputs, and HTTP headers enabling reflected attacks. We test reflected XSS vulnerability testing identifying script injection in GET/POST parameters, HTML injection in search queries, JavaScript injection in error messages, and client-side injection through URL manipulation. Our XSS security testing identifies reflected XSS through comprehensive cross-site scripting detection examining input reflection, insufficient output encoding including missing HTML encoding, inadequate input validation, and XSS filter bypass testing enabling attackers to inject malicious JavaScript through phishing links, weaponized URLs, and social engineering exploiting reflected attacks for immediate script injection execution without persistence enabling session hijacking, credential theft, and account compromise through XSS penetration testing exploitation.

Testing Focus: URL parameters, form inputs, HTTP headers, search functionality, error messages, input reflection, non-persistent attacks.

💾 Stored XSS Testing

Stored XSS testing examines persistent XSS vulnerabilities in database-stored content enabling stored attacks affecting all application users. We test stored XSS security testing identifying script injection in comments, HTML injection in user profiles, JavaScript injection in forum posts, and client-side injection in messages through comprehensive XSS vulnerability assessment. Our XSS penetration testing identifies persistent XSS through stored XSS testing examining database-stored content, insufficient output encoding and HTML encoding during content retrieval, inadequate input validation during storage, and XSS prevention testing failures enabling attackers to inject malicious payloads affecting every user viewing compromised content achieving mass account compromise, widespread session hijacking, and complete application compromise through stored attacks persistence.

Testing Focus: User profiles, comments, forum posts, messages, file uploads, persistent data, database-stored content, mass exploitation.

🎯 DOM-Based XSS Testing

DOM-based XSS testing examines client-side DOM manipulation vulnerabilities enabling DOM-based XSS through JavaScript execution. We test DOM-based XSS testing services identifying script injection through document.write, HTML injection via innerHTML, JavaScript injection through eval(), and client-side injection exploiting unsafe DOM APIs through comprehensive JavaScript security testing. Our XSS security testing identifies DOM-based XSS through DOM manipulation examining location.hash usage, window.name exploitation, postMessage vulnerabilities, and client-side routing weaknesses requiring manual XSS testing expertise understanding JavaScript execution contexts and DOM APIs enabling attackers to bypass server-side XSS filters achieving complete client-side script injection without server interaction through pure DOM manipulation exploitation.

Testing Focus: DOM APIs, innerHTML usage, document.write, eval() functions, location.hash, window.name, postMessage, client-side routing.

👁️ Blind XSS Testing

Blind XSS testing examines XSS vulnerabilities in backend systems and admin panels without immediate feedback. We test blind XSS testing identifying script injection in log viewers, HTML injection in admin dashboards, JavaScript injection in monitoring tools, and client-side injection in support tickets through comprehensive XSS vulnerability scanning. Our XSS penetration testing identifies blind XSS using external callback servers for cross-site scripting detection, DNS exfiltration for confirmation, HTTP callbacks for exploitation validation, and out-of-band techniques requiring specialized manual XSS testing enabling attackers to compromise administrator accounts, internal systems, and privileged users through delayed script injection execution in trusted internal applications achieving complete infrastructure compromise through blind XSS exploitation.

Testing Focus: Admin panels, log viewers, monitoring tools, support tickets, backend systems, external callbacks, delayed execution.

🔓 XSS Filter Bypass Testing

XSS filter bypass testing examines filter evasion techniques, encoding bypass methods, and WAF bypass strategies circumventing XSS prevention mechanisms. We test XSS filter bypass testing identifying JavaScript obfuscation techniques, encoding bypass through alternative encodings, filter evasion using polyglot payloads, and WAF bypass through mutation testing. Our comprehensive XSS security audit validates XSS filters effectiveness examining blacklist bypass, whitelist circumvention, context confusion, and encoding variations including HTML encoding bypass, JavaScript encoding evasion, and URL encoding manipulation enabling attackers to bypass XSS filters, circumvent WAFs, evade detection through JavaScript obfuscation, and achieve script injection through filter evasion despite XSS prevention testing implementation and XSS prevention mechanism testing validation.

Testing Focus: Filter evasion, encoding bypass, WAF bypass, JavaScript obfuscation, polyglot payloads, mutation testing, blacklist bypass.

🛡️ Content Security Policy Testing

Content security policy testing examines CSP headers implementation, CSP bypass techniques, and content security policy effectiveness preventing XSS exploitation. We test content security policy testing validating CSP headers configuration, CSP directives, unsafe-inline restrictions, and CSP bypass methods through comprehensive XSS security testing. Our XSS security audit identifies content security policy weaknesses including permissive CSP headers, missing script-src directives, unsafe-inline allowances, unsafe-eval permissions, and CSP bypass through JSONP endpoints, subdomain takeover, and CSP injection enabling attackers to bypass content security policy achieving script injection despite CSP implementation through CSP misconfiguration and content security policy testing failures requiring proper CSP headers enforcement and X-XSS-Protection configuration.

Testing Focus: CSP headers, CSP directives, unsafe-inline, unsafe-eval, CSP bypass, JSONP endpoints, X-XSS-Protection.

⚛️ Framework-Specific XSS Testing

Framework-specific XSS testing examines JavaScript security testing in React, Angular, Vue.js, and other frameworks. We test framework-specific XSS identifying dangerouslySetInnerHTML abuse in React, bypassSecurityTrustHtml misuse in Angular, v-html directive vulnerabilities in Vue.js, and template injection through comprehensive JavaScript security testing. Our XSS vulnerability assessment identifies framework-specific XSS through client-side injection examining server-side rendering vulnerabilities, template engine weaknesses, client-side routing exploitation, and framework API misuse requiring specialized manual XSS testing understanding framework internals enabling attackers to bypass built-in XSS protections achieving script injection through framework-specific vectors and JavaScript injection despite framework security features through improper usage and framework-specific XSS exploitation.

Testing Focus: React dangerouslySetInnerHTML, Angular bypassSecurityTrust, Vue v-html, template injection, SSR vulnerabilities, framework APIs.

🧬 Mutation XSS Testing

Mutation XSS testing examines browser-specific parsing vulnerabilities and mutation testing techniques. We test mutation XSS testing identifying browser DOM parsing inconsistencies, HTML sanitizer bypass through mutation, and browser-specific XSS through comprehensive cross-site scripting assessment. Our XSS penetration testing identifies mutation XSS through mutation testing examining mXSS vectors, namespace confusion, SVG context switching, MathML exploitation, and browser parsing quirks requiring expert manual XSS testing understanding browser internals enabling attackers to bypass HTML sanitizers, DOMPurify restrictions, and server-side filtering achieving script injection through browser mutation after sanitization through DOM parser differences and mutation XSS exploitation despite XSS prevention mechanism testing validation and sanitization implementation.

Testing Focus: Browser parsing, DOM mutation, mXSS vectors, namespace confusion, SVG/MathML, sanitizer bypass, parser quirks.

📝 HTML Injection Testing

HTML injection testing examines HTML injection vulnerabilities enabling content spoofing, phishing, and defacement. We test HTML injection testing identifying markup injection in rich text editors, HTML injection in WYSIWYG editors, tag injection in markdown parsers, and content injection through comprehensive XSS vulnerability scanning. Our XSS security testing identifies HTML injection through cross-site scripting detection examining img tag injection, iframe injection, form injection for phishing, meta tag injection, and link injection requiring manual XSS testing distinguishing HTML injection from JavaScript injection enabling attackers to inject malicious HTML achieving phishing page injection, UI redressing, clickjacking setup, defacement, and social engineering attacks through HTML injection despite XSS prevention testing focusing primarily on script injection.

Testing Focus: Rich text editors, WYSIWYG, markdown injection, img tags, iframe injection, form injection, phishing, defacement.

🔐 XSS Prevention Testing

XSS prevention testing and XSS prevention mechanism testing examine XSS security controls effectiveness. We test input validation implementation, output encoding validation including context-aware encoding for HTML encoding, JavaScript encoding, and URL encoding, XSS filters effectiveness, HTTPOnly cookies implementation, and secure cookies configuration through comprehensive XSS remediation testing. Our XSS security audit identifies XSS prevention testing failures including missing output encoding, inadequate input validation, weak XSS filters, missing HTTPOnly flags on secure cookies, absent content security policy with CSP headers, improper same-origin policy enforcement, insecure CORS policy, and missing X-XSS-Protection enabling script injection, HTML injection, JavaScript injection, and all client-side injection through XSS prevention mechanism testing gaps and XSS security testing failures.

Testing Focus: Input validation, output encoding, context-aware encoding, XSS filters, HTTPOnly cookies, CSP, same-origin policy.

XSS Security Specialists

Our team specializes in XSS security testing with extensive cross-site scripting testing expertise. They have performed 4,200+ comprehensive XSS vulnerability assessment projects identifying 28,000+ XSS vulnerabilities. Our certified XSS penetration testing experts understand reflected XSS testing, stored XSS testing, DOM-based XSS testing, blind XSS testing, XSS filter bypass testing using filter evasion and encoding bypass, mutation XSS testing, framework-specific XSS, and all client-side injection vectors ensuring comprehensive XSS security audit and complete web application XSS testing coverage.

• XSS security certified
• 10+ years XSS expertise
• 4,200+ apps tested
• All XSS types covered

Manual + Automated XSS Testing

We combine automated XSS testing using XSS vulnerability scanning tools with expert manual XSS testing ensuring comprehensive cross-site scripting detection coverage. Automated tools identify obvious script injection while manual XSS testing discovers complex DOM-based XSS testing vulnerabilities, blind XSS testing vectors, mutation XSS testing issues, and XSS filter bypass testing techniques that automated scanners miss ensuring complete XSS vulnerability assessment, thorough XSS security testing, and comprehensive web application XSS testing across all injection contexts and client-side injection vectors.

• Automated XSS scanning
• Expert manual validation
• DOM-based XSS discovery
• Filter bypass expertise

All XSS Types Tested

Our XSS testing services cover reflected XSS vulnerability testing for non-persistent XSS, stored XSS security testing for persistent XSS attacks, DOM-based XSS testing services examining DOM manipulation, blind XSS testing using external callbacks, XSS filter bypass testing with JavaScript obfuscation and encoding bypass and filter evasion, content security policy testing validating CSP headers, mutation XSS testing, framework-specific XSS in React/Angular/Vue, HTML injection testing, and JavaScript security testing ensuring comprehensive XSS penetration testing coverage across all script injection, HTML injection, and client-side injection attack vectors.

• Reflected & stored XSS
• DOM-based XSS testing
• Filter bypass techniques
• Framework-specific XSS

Detailed XSS Security Report

Every XSS security audit includes comprehensive documentation covering all XSS vulnerabilities discovered through cross-site scripting detection, exploitation proof-of-concepts demonstrating script injection impact, affected parameters and injection contexts, reflected XSS testing and stored XSS testing findings, DOM-based XSS testing vectors, output encoding examples for HTML encoding and JavaScript encoding, input validation recommendations, content security policy testing guidance for CSP headers implementation, and detailed XSS remediation testing instructions helping development teams implement proper XSS prevention testing and XSS prevention mechanism testing.

• Executive summary
• Exploitation PoCs
• Encoding examples
• CSP configuration

Filter Bypass Expertise

Our XSS penetration testing includes comprehensive XSS filter bypass testing examining filter evasion techniques, encoding bypass methods using alternative HTML encoding and JavaScript encoding, WAF bypass strategies, JavaScript obfuscation, polyglot payloads for cross-context injection, and mutation testing for browser-specific vulnerabilities. We test XSS filters effectiveness, blacklist bypass, whitelist circumvention, and context confusion ensuring complete XSS security testing validating XSS prevention mechanisms against advanced filter evasion and encoding bypass techniques through comprehensive XSS filter bypass testing and XSS security assessment.

• Filter evasion testing
• Encoding bypass techniques
• WAF bypass strategies
• Polyglot payloads

XSS Remediation Support

Professional XSS testing services include ongoing XSS remediation testing support, output encoding implementation guidance for proper HTML encoding and JavaScript encoding and URL encoding, input validation best practices, content security policy testing assistance for CSP headers configuration, X-XSS-Protection setup, HTTPOnly cookies implementation on secure cookies, and free comprehensive re-testing. We help development teams implement context-aware encoding, effective XSS filters, and maintain ongoing XSS security testing ensuring continuous XSS prevention testing and complete web application XSS testing protection.

• 60-day remediation support
• Encoding implementation help
• CSP configuration guidance
• Free comprehensive re-testing

Injection Point Discovery

Context Mapping:

• Input parameter identification for XSS testing
• Injection context analysis for XSS security testing
• Output reflection mapping for cross-site scripting detection
• DOM sink discovery for DOM-based XSS testing
• JavaScript context enumeration
• Client-side injection surface mapping

Automated XSS Scanning

Tool-Based Detection:

• Automated XSS testing with XSS vulnerability scanning
• Reflected XSS testing for non-persistent XSS
• Stored XSS testing for persistent XSS
• Basic script injection and HTML injection detection
• Initial cross-site scripting detection and XSS vulnerability assessment
• Baseline vulnerability mapping for manual XSS testing

Manual XSS Exploitation

Expert Testing:

• DOM-based XSS testing through DOM manipulation
• Blind XSS testing with external callbacks
• XSS filter bypass testing using filter evasion
• JavaScript obfuscation and encoding bypass
• Mutation XSS testing for browser quirks
• Framework-specific XSS and polyglot payloads

XSS Security Report & Remediation

Documentation:

• XSS security audit report with all vulnerabilities
• Exploitation PoCs for script injection and HTML injection
• Output encoding examples for HTML encoding & JavaScript encoding
• Content security policy testing recommendations for CSP headers
• XSS remediation testing instructions and fixes
• 60-day support including XSS prevention testing validation

Basic XSS Testing

Essential XSS security

Small applications

• Automated XSS testing and XSS vulnerability scanning
• Reflected XSS testing
• Stored XSS testing
• Basic HTML injection testing
• Input parameter XSS security testing
• XSS testing report
• 30-day support

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Professional XSS Testing

Comprehensive XSS security

Most applications

• Automated + manual XSS testing comprehensive
• Reflected XSS vulnerability testing
• Stored XSS security testing complete
• DOM-based XSS testing services
• Blind XSS testing with callbacks
• XSS filter bypass testing
• Content security policy testing and CSP headers
• JavaScript security testing
• HTML injection testing complete
• Framework-specific XSS testing
• Executive presentation
• 60-day support
• One free re-test

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Enterprise XSS Security

Complete XSS penetration testing

Complex enterprise systems

• Complete XSS penetration testing coverage
• All reflected XSS testing and stored XSS testing
• Advanced DOM-based XSS testing
• Blind XSS testing comprehensive
• XSS filter bypass testing expert-level
• Mutation XSS testing
• Framework-specific XSS all frameworks
• JavaScript security testing advanced
• Content security policy testing complete CSP audit
• Polyglot payloads and JavaScript obfuscation
• WAF bypass and encoding bypass testing
• Complete XSS prevention mechanism testing
• Executive presentation with Q&A
• 90-day premium support
• Unlimited XSS remediation testing and re-testing

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SafetyBis XSS testing discovered 67 DOM-based XSS testing vulnerabilities through DOM manipulation that automated XSS vulnerability scanning tools missed. Their XSS filter bypass testing found encoding bypass techniques circumventing our WAF. The blind XSS testing prevented admin account compromise. Professional cross-site scripting assessment that saved us from client-side injection attacks!

We thought our React app was safe until their framework-specific XSS testing found dangerouslySetInnerHTML vulnerabilities. The stored XSS security testing identified persistent XSS in user comments affecting all visitors. The content security policy testing secured our CSP headers implementation. Best JavaScript security testing and XSS security audit we’ve experienced!

Their reflected XSS vulnerability testing found non-persistent XSS in our search functionality enabling session hijacking through reflected attacks. The mutation XSS testing discovered browser-specific vulnerabilities. Certified XSS penetration testing experts understanding JavaScript injection, HTML injection, and script injection deeply. Highly recommend their XSS testing services!

What is XSS testing?

XSS testing and cross-site scripting testing are specialized security assessments examining client-side injection vulnerabilities. Professional XSS penetration testing evaluates script injection, HTML injection, and JavaScript injection through reflected XSS testing for non-persistent XSS, stored XSS testing for persistent XSS attacks, DOM-based XSS testing examining DOM manipulation, blind XSS testing using external callbacks, XSS filter bypass testing through filter evasion and encoding bypass, mutation XSS testing, framework-specific XSS, and HTML injection testing. Comprehensive XSS vulnerability assessment identifies all client-side injection vectors enabling session hijacking, credential theft, and account compromise through JavaScript injection exploitation using automated XSS testing combined with expert manual XSS testing following XSS testing methodology and XSS security testing checklist.

How much does XSS testing cost?

XSS testing cost varies based on application complexity and injection contexts. Basic XSS security testing and automated XSS testing costs $2,000-3,500 for simple applications with limited input points. Professional cross-site scripting testing ranges $6,500-8,500 for comprehensive testing including DOM-based XSS testing, blind XSS testing, and manual XSS testing validation. Enterprise XSS penetration testing and complete XSS vulnerability assessment costs $12,000-15,000 for complex applications with framework-specific XSS testing, XSS filter bypass testing, and mutation XSS testing. Investment in professional XSS testing services prevents XSS breaches averaging $3.9 million making XSS security testing extremely cost-effective for web application security.

Do you test all XSS types?

Yes! Our XSS testing services include reflected XSS vulnerability testing for non-persistent XSS in URL parameters and form inputs through reflected attacks, stored XSS security testing for persistent XSS in database content enabling stored attacks, DOM-based XSS testing services examining DOM manipulation and client-side JavaScript execution, blind XSS testing using external callback servers for delayed exploitation, XSS filter bypass testing through filter evasion techniques and encoding bypass methods and WAF bypass, mutation XSS testing identifying browser parsing vulnerabilities, framework-specific XSS testing in React/Angular/Vue, self-XSS testing, HTML injection testing, and JavaScript security testing. Each XSS type requires specialized cross-site scripting detection expertise ensuring comprehensive XSS vulnerability assessment coverage across all client-side injection vectors and injection contexts.

What XSS vulnerabilities do you test for?

Our comprehensive XSS security audit tests reflected XSS through input reflection and insufficient output encoding, stored XSS in database-stored content, DOM-based XSS through unsafe DOM APIs and DOM manipulation, blind XSS in backend systems, script injection in all contexts, HTML injection for content spoofing, JavaScript injection through eval() and innerHTML, inadequate input validation, missing HTML encoding and JavaScript encoding and URL encoding through output encoding failures, weak content security policy with permissive CSP headers, missing X-XSS-Protection headers, insecure HTTPOnly cookies and secure cookies implementation, XSS filter weaknesses enabling filter evasion and encoding bypass, WAF bypass vulnerabilities, JavaScript obfuscation resistance, polyglot payloads effectiveness, mutation XSS through browser parsing, and framework-specific XSS in React dangerouslySetInnerHTML and Angular bypassSecurityTrust ensuring complete XSS vulnerability assessment and comprehensive XSS security testing.

How often should we perform XSS testing?

Minimum: annual comprehensive XSS penetration testing and complete XSS security testing for all web applications. Recommended: XSS testing after code changes, new features with user input, framework updates requiring framework-specific XSS testing, or content security policy testing modifications to CSP headers. Best practice: continuous XSS testing throughout development lifecycle catching XSS vulnerability assessment issues early through automated XSS testing integrated in CI/CD. Essential: immediate cross-site scripting testing after discovering vulnerabilities in libraries, frameworks, or similar applications. Regular professional XSS testing services maintain ongoing XSS security testing and web application XSS testing preventing exploitation of script injection, HTML injection, JavaScript injection, and all client-side injection through reflected XSS testing, stored XSS testing, and DOM-based XSS testing requiring continuous XSS prevention testing validation and output encoding verification.

What’s included in the XSS security report?

Every XSS security audit includes comprehensive documentation covering executive summary, all XSS vulnerabilities discovered through cross-site scripting detection, exploitation proof-of-concepts demonstrating script injection and HTML injection impact, affected parameters and injection contexts, reflected XSS testing and stored XSS testing findings, DOM-based XSS testing vectors through DOM manipulation, blind XSS testing results, XSS filter bypass testing techniques including filter evasion and encoding bypass, output encoding examples for HTML encoding and JavaScript encoding and URL encoding implementation, input validation recommendations, content security policy testing guidance for CSP headers configuration including CSP directives and X-XSS-Protection, HTTPOnly cookies and secure cookies implementation, same-origin policy and CORS policy security, XSS remediation testing instructions with code fixes, framework-specific XSS prevention, and detailed XSS prevention testing best practices ensuring development teams implement proper output encoding, effective input validation, and context-aware encoding preventing all script injection, HTML injection, JavaScript injection, and client-side injection through XSS prevention mechanism testing implementation.

4,200+ Apps Tested

XSS testing expertise

XSS Certified

Security specialists

All XSS Types

Complete coverage

60-Day Support

Remediation help