Professional Experience
Resola INC
Aug 2025 โ Present
Cloud Security Engineer
- AWS Security Architecture: Design and implement secure architectures using VPC, Security Groups, IAM policies, and AWS Organizations across multi-account environments.
- Cloud Security Monitoring: Deploy and manage CloudTrail, GuardDuty, Security Hub, and Config; integrate SIEM with cloud-native services for unified visibility.
- Identity & Access Management: Implement IAM best practices, RBAC, MFA enforcement, and identity federation; conduct regular access reviews and privilege escalation testing.
- Compliance & Governance: Automate compliance checks using Config Rules and Lambda aligned with the CIS AWS Foundations Benchmark.
- IaC Security: Review Terraform/CloudFormation templates; implement automated security scanning in CI/CD pipelines using Checkov and TFSec.
- Container & Serverless Security: Secure containerized workloads on ECS/EKS and Lambda; enforce image scanning via ECR and runtime policy enforcement.
VNPAY
Mar 2024 โ Jul 2025
Security Engineer
- Penetration Testing: Conducted black-box and grey-box assessments for internal WAF, payment gateways, and new product releases; identified and tracked critical vulnerabilities through remediation.
- SOC & SIEM: Led Wazuh and Splunk deployment for 24/7 monitoring across 500+ endpoints; designed custom threat detection rules based on MITRE ATT&CK framework; reduced false positives by 40%.
- PCI-DSS Compliance: Maintained ongoing PCI-DSS compliance posture; conducted quarterly security risk assessments and vulnerability management cycles.
- Incident Response: Led security investigations end-to-end; authored IR playbooks; coordinated cross-team remediation with development and infrastructure teams.
- Automation: Developed Python/Bash scripts to automate repetitive assessment and log parsing workflows, accelerating analyst throughput.
VNPAY
Aug 2023 โ Feb 2024
Cloud Security Intern
- Supported distributed SIEM deployment in hybrid cloud environments; optimized log collection pipelines across multi-cloud infrastructure.
- Developed Python parsers for automated CVE analysis and risk-based prioritization.
- Configured Splunk dashboards for real-time security event monitoring and alerting.
Bug Bounty & Vulnerability Research
168
Reputation
4
Valid Findings
$250
Bounties Earned
Vulnerability Finding #1 โ Enjin Platform
Medium
Discovered and responsibly disclosed a valid security vulnerability on the Enjin blockchain gaming platform, resulting in a rewarded bug bounty.
๐ฐ Rewarded: $150 ยท Resolved by program
Vulnerability Finding #2 โ Enjin Platform
Low
Second distinct vulnerability reported and triaged on the Enjin program with confirmed security impact assessment.
๐ฐ Rewarded: $100 ยท Resolved by program
Open-Source Security Advisories (GHSA / CVE)
GHSA-7h52-2rwr-m76r / CVE-2026-92087 —
@fastify/auth: Authorization Bypass via Order-Dependent Evaluation
High · CVSS 8.1
Discovered and responsibly disclosed an authorization bypass in @fastify/auth, the official Fastify auth-composition plugin (~420K weekly npm downloads). The composition engine stored its verdict in a single mutable
currentError field that later callbacks overwrote unconditionally, so a nested AND/OR group's result was masked by whichever function ran last — a request satisfying neither side of the documented expression was authorized with 200 instead of 401. Two configurations affected, including plain { relation: 'and' } with a nested OR group on default options. Submitted a working proof of concept across both cases; fixed in 5.1.1 by latching group verdicts and short-circuiting a failing group.
GHSA-rc93-2r6p-hc2q โ
mssql (node-mssql): T-SQL Identifier Injection
High ยท CVSS 8.1
Independently discovered and responsibly disclosed the column-name injection in the node-mssql SQL Server client (~1.65M weekly npm downloads).
Table.declare() interpolated column names straight into CREATE TABLE DDL as [name] without doubling embedded ], so a name sourced from an uploaded CSV/XLSX header could close the quoted identifier and append arbitrary stacked T-SQL to the batch run by bulk({ create: true }). Submitted a working proof of concept and a patch; the coordinated fix now rejects unescaped identifiers (EINJECT) across parameter, column, type and procedure names.
GHSA-j939-289f-wq4w โ
openapi-backend: Fail-Open Authorization
High ยท CVSS 8.2
Discovered and responsibly disclosed a fail-open authorization flaw in the openapi-backend npm package (โค 5.17.0). Security handlers returning a truthy
error object with additional properties were incorrectly treated as authorization success, allowing unauthenticated requests to reach protected operations. Patched in 5.18.0 by treating any truthy error value as failed authorization.
Reported Upstream — No Advisory Issued
fast-json-stringify: Code Injection via Crafted JSON-Schema Property Name
Reporter-rated Critical
Reported a code injection flaw in fast-json-stringify, the serializer behind Fastify’s response path (~18M weekly npm downloads). Property names taken from a JSON schema were emitted into the generated serializer source without neutralisation, so a schema reachable from untrusted input could run attacker-controlled JavaScript in the host process. Submitted with a working proof of concept against ≤ 7.0.0. Fastify’s threat model treats schemas as trusted input, so the advisory was not accepted; the property-name escaping was nonetheless corrected upstream in 7.1.0.
probe-image-size: Server-Side Request Forgery
Reporter-rated Critical
Reported a server-side request forgery in probe-image-size (~7M weekly npm downloads), a library whose documented entry point fetches a caller-supplied image URL. The fetch applied no containment against internal network destinations. Submitted with a working proof of concept. The maintainers did not accept the advisory. Details held back, as no fixed release has shipped.
Additional advisories in disclosure pipeline
Pending
Further vulnerabilities reported to open-source maintainers โ awaiting vendor confirmation and coordinated public disclosure.
Under embargo ยท details published once GHSAs are live
hackerone.com/sengtocxoen
Signal: 1.67 (63rd percentile) ยท Impact: 15.00 (76th percentile)
Notable Projects
SAST MCP โ AI-Powered Security Automation Platform
2025
Open-source MCP server integrating 23+ security tools (Semgrep, Bandit, TruffleHog, Gitleaks, Checkov, Trivy, Nmap, SQLMap) with Claude AI for automated security analysis through natural language. Built distributed architecture for Windows-to-Kali remote scanning with TOON format achieving 30โ60% token reduction.
PythonFlaskMCP SDKDockerSemgrepClaude AI
โ github.com/Sengtocxoen/sast-mcp
AWS Multi-Account Security Framework
2025
Centralized security monitoring for multi-account AWS using Organizations, Security Hub, and GuardDuty. Automated compliance checks with Config/Lambda via Terraform. Achieved 95% CIS AWS Benchmark compliance; reduced misconfigurations by 60%.
AWS OrganizationsSecurity HubGuardDutyTerraformLambda
Automated Threat Detection Platform
2024
API Gateway anomaly detection using BERT language models and Python. Developed log collection pipeline with real-time SIEM integration for ML-driven threat hunting.
PythonBERTElasticsearchKibanaDockerAWS Lambda
Cloud SIEM Integration & Automation
2024
Integrated Wazuh with AWS CloudTrail, GuardDuty, and VPC Flow Logs. Developed Python scripts for threat intelligence enrichment and automated incident response. Reduced MTTD by 45%; automated 70% of security alerts.
WazuhCloudTrailGuardDutyPythonVPC Flow Logs
Technical Skills
Cloud Security (AWS)
Penetration Testing
SOC & SIEM
Programming
Education
University of Information Technology โ VNU-HCM
B.Eng. Information Security ยท Talented Engineer Program
Research focus: ML-based API Attack Detection ยท High-performance SIEM Architecture ยท Security in Microservices
2020 โ 2024
Viettel Digital Talent 2023 (VDT)
Information Security Training
Advanced Web Application Pentesting ยท SIEM Architecture ยท Threat Hunting ยท Incident Response
Mar โ Jun 2023
Certifications & Training
- AWS Certified Security โ Specialty (In Progress)
- TryHackMe: SOC Analyst Level 1โ2 ยท Penetration Tester Path ยท Red Team Path ยท Cloud Security (AWS)
- HackTheBox: Pro-Hacker level ยท Bug Bounty Hunter Path (In Progress) ยท Cloud Pentester (In Progress)
- HackerOne Bug Bounty: Active researcher โ @sengtocxoen ยท Reputation 168 ยท 4 resolved reports
- Other Training: CIS AWS Foundations Benchmark ยท OWASP API Security Top 10 ยท Container Security
- CTF Participation: LA CTF 2025 ยท NahamCon CTF 2025