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Toss

Fintech super-app for payments and banking

Security Engineer - Security Infrastructure

Security Engineering & ArchitectureConfirmed live in the last 24 hours
Full-timeSeoul, South KoreaNo salary listedIn-person

About the Job

Requirements

  • Experience designing and building network security control architectures, analyzing network structures and traffic characteristics, and eliminating visibility and control gaps.
  • Experience understanding service architectures and traffic flows and directly designing and implementing security controls that account for security requirements and service availability.
  • Experience analyzing packets, flows, and cloud logs to determine root causes of security issues in network and cloud infrastructure and building prevention systems.
  • Experience defining consistent security standards for network configurations and cloud resource settings in large-scale hybrid on-premises and public-cloud environments, and designing and operating security architectures to maintain those standards.
  • Experience designing and implementing detection rules, blocking policies, and monitoring logic based on threats in endpoint environments.
  • Experience designing and implementing technical solutions such as policy exceptions, temporary access grants, and selective monitoring so that security controls do not disrupt business workflows.
  • Experience investigating endpoint security issues through log analysis, process tracing, and filesystem examination on Windows and macOS, and implementing measures to prevent recurrence.
  • Experience designing and operating management systems that maintain consistent security standards throughout the device lifecycle, from provisioning through retirement.

Responsibilities

  • Identify and resolve infrastructure security threats, data-exfiltration paths, and potential compliance violations across on-premises and cloud environments supporting customer services.
  • Design and implement security controls that meet security requirements while preserving service availability and usability, taking service architecture and employee work environments into account.
  • Analyze systemic causes of infrastructure security issues and improve architectures to prevent recurrence rather than handling incidents in isolation.
  • Maintain consistent security standards across hybrid infrastructure spanning on-premises systems and cloud environments.
  • Define security standards for cloud accounts and workloads, including network configuration, permission boundaries, and external exposure, and build systems that quickly detect and remediate deviations.
  • Establish visibility into internal East-West traffic, including Kubernetes environments, and develop microsegmentation-based controls.
  • Design and implement network-path enforcement of SSE- and ZTNA-based controls integrated with policy decision processes, while meeting financial-sector regulations such as network separation and making Zero Trust effective.
  • Design and implement endpoint access decisions using endpoint status collected through security-solution APIs, including implementation of a Policy Decision Point.
  • Integrate endpoint security context, such as device compliance and threat-detection results, with access controls in IAM, network, and application layers through SCIM, webhooks, and APIs.

Desired Qualifications

  • Experience operating or evaluating and designing cloud and container security approaches, including CNAPP, CSPM, CWPP, CIEM, microsegmentation, Kubernetes Network Policy, eBPF/Cilium, or service mesh.
  • Experience designing security functions for networking, IAM, and logging in public clouds such as AWS, Azure, or GCP, and automating security infrastructure deployment and operations using infrastructure as code such as Terraform, Python or Go, or AI/MCP-based tools.
  • Experience designing SSE- or ZTNA-based access-control architectures or transitioning existing network security systems.
  • Experience implementing regulatory requirements such as network separation and cloud-use regulations as technical controls in financial or other regulated environments.
  • Experience using Python, Go, OPA, or AI/MCP-based tools to implement endpoint-security-context-based access decisions.
  • Experience linking endpoint-collected security context, such as device compliance and threat-detection results, to IAM, network, and application-layer access controls through SCIM, webhooks, or APIs.

About the Company

Toss

Fintech super-app for payments and banking

Toss is a South Korean financial services platform that started as a peer-to-peer money transfer service and has grown into a digital 'super app' for personal finance. Its products are accessed through one mobile interface that unifies bank accounts, credit cards, loans, investments, and other financial services, including its own Toss Bank and Toss Securities. It differentiates itself by offering a broad, integrated ecosystem—combining digital banking, asset management, and brokerage services under one roof and running its own banking and securities units. Its goal is to become the leading consumer finance platform in South Korea while expanding its user base globally.

Company size
1,001-5,000
Company stage
Series G
Total funding
$1.5B
Headquarters
Seoul, South Korea
Founded
2011

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