Security Researcher / Penetration Tester

Madhusudan Acharya
0x4d5341

I break things so you don't have to. Specializing in web application security, vulnerability research, and penetration testing. Bug bounty hunter with findings acknowledged across multiple platforms.

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Web Application Pentesting

Comprehensive security assessment of web applications including OWASP Top 10, business logic flaws, authentication bypass, and authorization issues.

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API Security Testing

In-depth testing of REST and GraphQL APIs for broken access controls, injection flaws, rate limiting issues, and data exposure vulnerabilities.

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Network Pentesting

External and internal network penetration testing to identify misconfigurations, exposed services, and exploitable vulnerabilities across your infrastructure.

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Mobile Application Security

Security assessment of Android and iOS applications including reverse engineering, insecure data storage, and client-server communication analysis.

How I Found an IDOR Leading to Full Account Takeover Business Logic Bugs: The Vulnerabilities Scanners Miss
All writeups →

I provide professional penetration testing reports with detailed findings, severity ratings, reproduction steps, and remediation guidance. Below are sample assessment categories. Reach out to discuss your security needs.

Web Application Assessment Full-scope pentest covering authentication, authorization, injection, and business logic
SAMPLE
API Security Assessment Endpoint enumeration, access control testing, and data exposure analysis
SAMPLE
Vulnerability Disclosure Report Responsible disclosure template with impact, PoC, and fix recommendations
SAMPLE

I'm Madhusudan Acharya, a security researcher and penetration tester based in Sydney, Australia. Previously at Threatnix Nepal where I focused on web application security research. Currently pursuing a Master's in Information Technology with a specialization in Cybersecurity.


As an active bug bounty hunter since 2021, I've identified and responsibly disclosed vulnerabilities across multiple platforms including HackerOne and Bugcrowd. My focus areas include IDOR, XSS, business logic vulnerabilities, SSRF, and access control issues.

50K+
USD in Bounties
2021
Hunting Since
MSA
0x4d5341