Alexander Sideris
Information Systems Security Officer @Booz Allen Hamilton
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WORK HISTORY
Information Systems Security Officer @Booz Allen Hamilton
Huntsville, AL, US
Manages multiple ATO packages concurrently for AWS GovCloud and hybrid environments, ensuring full compliance with NIST SP 800-53 Rev. 5 across over security controls. Performs ACAS/Nessus and cloud-native vulnerability scans; generate and maintain POA & Ms for all findings that cannot be remediated within the required 60-day SLA. Drive continuous monitoring using Splunk dashboards (7-day rolling views), auditing users and system activity daily to detect and investigate security anomalies. Participates in Agile ceremonies and Program Increment (PI) planning; approve or deny change requests (CRs) based on security impact assessments and RMF alignment. Leverages Xacta to document RMF activities, track control implementation status, and facilitate automated compliance reporting across multiple system boundaries. Ensures robust integration of security into DevSecOps pipelines by collaborating with development teams on secure CI/CD processes and shift-left testing strategies. Authors and maintain all system documentation including BIA, ISCP, CMP, and contingency plans; lead contingency plan testing exercises and document results per NIST SP 800-34. Serve as a trusted liaison to ISSMs and Authorizing Officials (AOs), translating complex technical risks into actionable security posture decisions. Recognized for supporting and sustaining full ATOs across multiple high-impact, mission-critical systems in cloud-based and hybrid DoD environments. Developed a program that loads, cleans, and populates Nessus CSVs into a POAM report, reducing report creation time by 500%.
EDUCATION
Western Governors University
Bachelor's degree, Cybersecurity and Information Assurance
Western Governors University
Master of Science - MS, Cybersecurity and Information Assurance
ABOUT ALEXANDER SIDERIS
As an Information Assurance Officer at the FBI Redstone, I lead the management of multiple ATO packages in AWS GovCloud and hybrid environments, ensuring full compliance with NIST SP 800-53 Rev. 5 across over security controls. My role involves conducting ACAS/Nessus and cloud-native vulnerability scans, generating and maintaining POA & Ms for unresolved findings, and driving continuous security monitoring using Splunk dashboards to detect and investigate anomalies.I actively contribute to Agile ceremonies and Program Increment planning, making security decisions based on impact assessments and RMF alignment. With a strong focus on compliance, I leverage Xacta for documenting RMF activities and generating automated reports across system boundaries. In addition, I ensure seamless security integration into DevSecOps pipelines, collaborating closely with development teams on secure CI/CD processes and shift-left testing strategies.I am also responsible for authoring and maintaining critical documentation such as BIA, ISCP, CMP, and Incident Response plans, while leading testing exercises as per NIST SP 800-34. As a trusted liaison to ISSMs and Authorizing Officials, I translate complex technical risks into actionable security decisions. My work is recognized for sustaining full ATOs across high-impact, mission-critical systems and securing FBI SCIFs.
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