Freelancer profile translated to English.
Back to original languageAbout Quentin
Former pentester specializing in Red Team, I have focused my offensive expertise on securing Active Directory environments, whether on-premise or hybrid (Cloud).
I intervene in technical AD audits, post-compromise reconstruction, and hardening of sensitive infrastructures. My support extends to implementing recommendations: segmentation via authentication silos, secure bastion, AD/ADCS hardening, etc.
With a resolutely offensive approach, I transform identified vulnerabilities into levers of resilience, for sustainable environments against internal threats.
French
Native or bilingual
English
Fluent
Can work on-site
Paris (up to 50km)
Experience
- Bouygues TelecomActive Directory Security ExpertSeptember 2025 - Today (11 months)Meudon, FranceTech lead for the group's Active Directory securityCreation of security strategy and standardsSecurity audit and assessmentRecommendation and implementation of remediationBringing up to date and redesigning domain security projects
- AISI - Pure Player Infrastructure et CybersécuritéMICROSOFT ACTIVE DIRECTORY SECURITY CONSULTANTCONSULTING AND AUDITSJanuary 2023 - September 2025 (2 years and 8 months)Saint-Mandé, France
On-Premise Active Directory Audit & Security
Active Directory Security Audit:- Conducted comprehensive security audits of on-premise Active Directory environments.
*Analysis of privileged accounts(domain members, local administrators, services, accounts with non-expiring passwords, etc.).Post-compromise Reconstruction:*Active participation in AD reconstruction projects- **Implementation of a new Active Directory forest from scratch**, with immediate application of security best practices (strict tiering model, DC hardening, minimal access controls).
Post-Audit Support Missions:*Deployment of LAPS(Local Administrator Password Solution) for automatic rotation of local passwords.*GPO Security:cleaning, hardening, fine-grained delegation of modification rights, hardening of the environment.*Implementation of Authentication Silosto restrict the use of T0 accounts to specific machines only (PAWs and bastions).*Use of the "Protected Users" group(Kerberos, TGT LifeTime, Authentication Delegation...).*Implementation of Microsoft Credential Guard:isolation of authentication secrets (TGT, NTLM, etc.).*ADCS Hardening:removal of vulnerable templates, configuration of permissions on templates, disabling unnecessary HTTP services (EPA), 2-tier PKI: ROOT and Intermediate CA.*LDAPS Security:deployment of enterprise certificates on DCs*SMB Signing:mandatory activation of signing on servers and workstations to prevent MITM attacks. - IntrinsecPENTEST / RED TEAMCONSULTING AND AUDITSJanuary 2022 - January 2023 (1 year)Paris, FranceInternal Security Audit (Luxury Sector):
- Reconnaissance: Mapping the internal network.
- Exploitation: Exploiting vulnerabilities.
- Lateral Movement: Progression through the network.
- Domain Compromise: Taking control of the IS.
- Report Writing: Attack diagrams and recommendations.
- Presentation to senior management: Presentation of risks and strategic recommendations
Research and Development (R&D):- Development of Rubeus in C (parsing user sessions (LUID),
- parsing LSA, retrieving TGT/ST tickets in memory).
- Development of a Loader in C (mapping an exe in memory,
- indirect Syscalls, Callstack spoofing, dynamic encryption in
- memory, IAT hooking ..).
- Redevelopment of mimikatz module in C (MultiRDP..)
- Development of a tool to impersonate tokens
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Education
- MASTER 2 CYBERSECURITYESGI2023MASTER 2 CYBERSÉCURITÉ
- BACHELORESGI2021BACHELOR
Certifications
- Certified Red Team Professional (CRTP)Altered Security2022