Defending the Digital Frontier
Boutique cybersecurity advisory and penetration testing — protecting organizations worldwide from the threats of today and tomorrow.
Defensahacker Labs is a boutique cybersecurity consulting firm offering expert penetration testing services, smart contract security audits, and AI red teaming to organizations worldwide. Founded by a Certified Ethical Hacker (CEH) and Offensive Security Certified Professional (OSCP) with over two decades of hands-on experience — we help banks, fintechs, DeFi protocols, and enterprises identify and remediate critical vulnerabilities before attackers do.
We simulate real-world cyberattacks on your systems, networks, and applications to uncover vulnerabilities before malicious actors do — delivering a clear picture of your true risk exposure.
Assessments cover cloud environments, internal networks, mobile apps (Android & iOS), IoT, and OT infrastructure — validating the strength of your defenses across every attack surface.
Blockchain and DeFi protocols introduce unique security challenges that traditional testing misses. A single vulnerability in a smart contract can result in irreversible financial loss.
We go beyond the contract — auditing your entire ecosystem end-to-end, including Web2 components like frontends and DNS that account for most Web3 exploits.
As organizations rush to adopt generative AI, new attack surfaces emerge. Our AI Audits and GenAI Red Teaming identify vulnerabilities in AI pipelines, LLM integrations, and agentic systems.
We deliver actionable risk assessments aligned with OWASP GenAI Top 10, concrete remediation guidance, and compliance support — so your AI initiatives are both innovative and secure.
Ethical hacking involves simulated cyberattacks on systems, networks, and applications to identify vulnerabilities that malicious actors could exploit. It helps assess the effectiveness of existing security measures.
Having worked as a consultant and penetration tester for top-tier banks, the European Central Bank, pharmaceutical and automotive companies across several regions and continents — we have vast experience with all types of companies and engagements.
Get started todayWe don't run automated scanners and call it a pentest. Every engagement is led by a senior security engineer who thinks, moves, and pivots like an actual threat actor — uncovering logic flaws and chained vulnerabilities that tools miss.
Few consultants hold simultaneous expertise across traditional pentesting, blockchain security, and AI red teaming. We cover all three — giving clients a single trusted partner as their technology stack evolves.
Every finding includes a clear attack narrative, proof-of-concept, business impact assessment, and prioritized remediation steps — written for both technical teams and C-level stakeholders.
Trusted by Fortune 500 companies, global financial institutions, and cutting-edge Web3 protocols. Our work has been recognized in public bug bounty programs and resulted in published CVEs.
Certified Ethical Hacker, smart contracts auditor and lead security engineer with over 20 years of experience in cybersecurity, particularly within the banking and finance industries.
We have been impressed with this persistence in finding bugs, his ability to explain his findings and Mr. Avariento is a welcome and respected contributor to our Bounty program. We look forward to any additional submissions he provides.
Mr. Avariento was entrusted with the Technical Management of the Security Testing project team at the European Central Bank. He always fulfilled his tasks to our absolute satisfaction — an extremely skilled professional who always served customers courteously.
Hewlett Packard Enterprise would like to thank Jacobo Avariento, working with Defensahacker, for responsibly reporting CVE-2017-12544.
A penetration test (pentest) is a controlled, authorized simulation of a cyberattack against your systems, applications, or network. Unlike vulnerability scanning, a pentest involves a human attacker chaining together weaknesses to demonstrate real-world exploitability. Companies need pentesting to satisfy compliance requirements (PCI-DSS, ISO 27001, SOC 2), validate security investments, and discover hidden risks before malicious actors do. Most breaches exploit vulnerabilities that were present for months or years — regular pentesting closes that window.
Smart contracts execute autonomously on-chain and are immutable once deployed — there is no patch cycle for blockchain. A smart contract audit combines manual code review with automated formal analysis to identify reentrancy attacks, integer overflows, access control flaws, and economic manipulation vectors before deployment. We also audit the surrounding Web2 infrastructure (frontends, APIs, DNS) since over 60% of DeFi exploits target these off-chain components rather than the contract itself.
GenAI red teaming tests LLM-powered applications against adversarial attacks specific to generative AI: prompt injection, jailbreaking, data exfiltration via model outputs, insecure tool use, and agentic privilege escalation. If your product uses an LLM — as a chatbot, copilot, or autonomous agent — it has an attack surface that traditional security tools don't cover. We assess against the OWASP LLM Top 10 and provide actionable remediation guidance aligned with emerging AI security standards.
Scope determines timeline. A focused web application pentest typically runs 3–5 days. A full internal network assessment with Active Directory attacks spans 1–2 weeks. Smart contract audits for a medium-complexity protocol take 5–10 days of review. We always provide a detailed scope document and timeline estimate before any engagement begins, and we include a retest of all critical findings at no extra charge.
Both. As a boutique firm, we keep engagements lean and senior-led — which means we're accessible to early-stage startups and DeFi protocols that need expert-grade security without enterprise price tags. We've worked with everything from seed-stage Web3 projects to the European Central Bank. Every client gets direct access to the lead security engineer, not a project manager relaying findings.
Get in touch to discuss your security needs. Whether it's a penetration test, smart contract audit, or AI red team engagement — we're ready to help.