Senior Network Security Engineer (Cybersecurity Lead)

ThinkMarkets

Sofia, Bulgaria

We are seeking a Senior Network Security Engineer with a focus on Cybersecurity to join our rapidly growing global workforce in Sofia, Bulgaria. You will play a key role in safeguarding our financial platforms, customer data, and digital infrastructure against cyber threats. This role demands a strong understanding of financial systems, regulatory compliance, and emerging security technologies. You will serve as a network security leader and trusted authority within the networking domain.

Responsibilities:

Monitor and defend against cyber threats targeting financial systems and customer data;
Conduct regular vulnerability scans, penetration tests, and risk assessments;
Develop and enforce security policies, procedures, and best practices;
Manage and optimize SIEM, IDS/IPS, firewalls, and endpoint protection tools;
Investigate and respond to security incidents and breaches (e.g, DDoS attacks);
Stay current with emerging cybersecurity trends, threats, and technologies;
Collaborate with IT and engineering teams to ensure secure system architecture; maintain L2/L3 switches, routers, and firewalls;
Ensure compliance with financial regulations such as PCI-DSS, ISO 27001, GDPR, and FCA guidelines;
Drive implementation of network security best practices and contribute to infrastructure hardening efforts;
Lead performance analysis and latency optimization for mission-critical, customer-facing applications;
Contribute to disaster recovery, high availability, and security strategies in collaboration with other teams;
Proactively monitor network health and resolve performance bottlenecks or connectivity issues;
Respond flexibly to critical incidents outside normal working hours.

Requirements:

5+ years of hands-on experience in network security engineering, preferably in financial services or FinTech;
Bachelor’s degree in Cybersecurity, Computer Science, or a related field;
Certifications such as CISSP, CISM, CEH, or CompTIA Security+ (CISA or CRISC are a plus);
Strong understanding of firewalls, VPNs, IDS/IPS, and endpoint protection;
Advanced understanding of the TCP/IP stack and proficiency with network profiling tools such as Wireshark, Tenable, Splunk, CrowdStrike, etc.;
Proven experience in cybersecurity, IT security, or network administration;
Demonstrated ability to support and enhance latency-sensitive global networks;
Self-starter mindset with a collaborative attitude and a passion for solving complex problems;
Familiarity with SIEM tools and threat intelligence platforms;
Excellent problem-solving and analytical skills;
Strong communication skills in English, both written and verbal.