One Source · 18 hours ago
Senior Security & Systems Engineer
United States
Full-time
Remote
Senior Level
5+ years expOne Source is seeking a Senior Systems & Security Engineer who will be responsible for stabilizing and rebuilding client environments during cybersecurity incidents. The role involves working closely with the Incident Response team to manage threats, conduct root cause analysis, and enhance security measures.
Telecom & CommunicationsInformation TechnologyTelecommunications
Responsibilities
Respond to active security incidents including ransomware, account compromise, malware outbreaks, and lateral movement
Analyze endpoint, identity, network, and log telemetry to determine scope, root cause, and attacker behavior
Execute containment actions across endpoints, identity platforms, and network infrastructure
Support eradication and recovery efforts to ensure secure restoration of services
Provide clear technical direction during live incident response activities
Identify control failures, misconfigurations, and visibility gaps that enabled the incident
Design and implement remediation plans addressing both immediate threats and underlying weaknesses
Perform security hardening across endpoints, servers, identity systems, and networks
Remove persistence mechanisms and validate clean recovery
Rebuild security baselines to prevent repeat incidents
Deploy, configure, and maintain modern security platforms, including:
Endpoint Detection & Response (EDR)
Security telemetry and log analytics platforms (SIEM, XDR, log pipelines)
ELK / Elastic stack
Email Threat Protection
Integrate security telemetry and data sources to improve detection accuracy and investigation speed
Improve logging, alerting, and response workflows in environments with limited or fragmented visibility
Conduct post-incident assessments and gap analyses
Identify vulnerabilities, misconfigurations, and systemic security debt
Implement preventative controls to reduce attacker dwell time and blast radius
Support vulnerability management and long-term risk reduction initiatives
Secure identity platforms using Active Directory, LDAP, SAML, and OAuth
Respond to identity and cloud-centric incidents including SSO abuse, token theft, and SaaS compromise
Assess and harden network security controls including firewalls, IDS/IPS, VPNs, VLANs, and TLS
Apply cloud security best practices across AWS, Azure, and Google Cloud environments
Identify and mitigate common application security vulnerabilities such as SQL injection, XSS, and CSRF
Introduce scripting and automation (PowerShell, Python) to accelerate response and reduce manual effort
Document rebuilt architectures, security controls, and response procedures
Collaborate closely with the Cyber Security Incident Response Project Manager to align technical execution with timelines and deliverables
Provide technical guidance and mentorship during response and remediation efforts
Contribute to future-state security architecture and resilience planning
Qualification
Required
Ability to travel up to 50% of the time
5+ years of experience in information security with a strong focus on incident response and remediation
Demonstrated experience responding to real-world security incidents
Hands-on experience with EDR, security monitoring, and endpoint and identity remediation
Strong understanding of attacker techniques, lateral movement, and persistence mechanisms
Working knowledge of scripting and automation (PowerShell, Python)
Strong communication skills with experience supporting client-facing response efforts
Bachelor's degree in Computer Science, Information Security, or equivalent hands-on experience
Preferred
Security certifications such as CISSP, CISM, CEH, or CompTIA Security+ preferred
Experience in MSSP, consulting, or multi-client environments preferred
Company
One Source
One Source is a telecommunications company specializing in communications management and it service solutions.
201-500 employees
Funding
Current Stage
Growth StageLeadership Team
Tim Meng
CEO
John Young
Chief Technology Officer
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