The Quiet
Sentry.
Building systems, breaking assumptions, writing what I learn.
Santiago Andrade Ferreiro
Tech Lead & Offensive Security
I am a Tech Lead and Backend Developer operating under the alias BitSentry. My focus is security-by-design, building high-scale systems that remain resilient against modern threats.
At Councilbox, I own the product security posture, bridging core backend engineering with internal offensive audits and pentesting. My goal is to ensure security isn't a patch, but a native part of the software lifecycle.
Galicia Skills Gold Medalist and Spain Skills finalist. Independent security researcher and offensive lab enthusiast, focused on delivering technical value from the very first bit.
EXPERIENCE
Product Tech Lead & Offensive Security
2024 — NOWCOUNCILBOX
Own the product security posture, conducting internal Web/API pentests, phishing simulations, and offensive security audits. Deliver executive and technical reports aligned with Tier-1 external assessments.
Offensive SecurityInternal PentestsAppSec OwnershipOVAC ProductFullstack Developer (OVAC Product)
2022 — 2024COUNCILBOX
Developed core backend features, implemented secure system design, and supported product security initiatives through code reviews and threat analysis.
Backend CoreSecure ArchitectureOVAC ProductFullstack Developer
2021 — 2022AVA TECNOLOGÍA
Managed full-cycle web development projects with focus on scalable solutions and legacy system optimization.
LaravelPHPPerformance Optimization
EDUCATION
MSc in AI & Big Data
IES Fernando Wirtz
Adversarial ML & Neural Networks
MSc in Cybersecurity
IES San Clemente
Offensive Security & Pentesting
BSc in Web Development (DAW)
IES San Clemente
Software Engineering Fundamentals
The Vault
Tools and applications built with security and performance at their core.
Nukairo
Personal finance SaaS, secure-by-design. Backend robustness and privacy-first architecture.
Gqlonaut
Introspection module for Caido/GraphQL. Automated discovery for offensive security audits.
Git-Cleaner
CLI tool for automated git branch lifecycle management.
Offensive Lab
Professional certifications, offensive security methodology, and hands-on Red Team experience.
- Active
CEH
Certified Ethical Hacker
- 2026
OSCP
Offensive Security Certified Professional
- Ongoing
HTB
Active Offensive Security Labs
PENTEST METHODOLOGY
- 01Reconnaissance / OSINT
- 02Vulnerability Discovery
- 03Active Exploitation / Red Team Ops
- 04Technical & Executive Reporting
Research & Speaking
Vulnerability analysis in deep learning models and defense techniques.
Breaking Neural Networks: Backdoors & Adversarial AI
Presented at security conferences, exploring how minimal data perturbations (noise) can force misclassifications in critical systems.
ADVERSARIAL ML SPECIALISTProof-of-concept exploit
def craft_noise(img, eps):
grad = get_gradients(img)
# aplicar perturbación mínima
noise = eps * grad.sign()
adv_x = img + noise
return clamp(adv_x, 0, 1)Field notes
Notes on security, engineering and systems.