Job Title: Tenable / ACAS Administrator
Job Category: Information Technology
Time Type: Full time
Minimum Clearance Required to Start: Secret
Employee Type: Regular-Long Term Assignment
Percentage of Travel Required: Up to 10%
Type of Travel: Local
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The Opportunity
Are you interested in continuing your career in Europe in a mission-focused environment? CACI has an excellent opportunity for an
experienced, self-directed Information Systems Security Officer supporting U.S. Africa Command (AFRICOM) operations in Stuttgart,
Germany. This position is OCONUS and requires on-site presence.
We are seeking a qualified and experienced ACAS / Tenable Administrator to manage, maintain, and optimize our enterprise Assured Compliance Assessment Solution (ACAS) and Tenable vulnerability scanning infrastructure. In this role, you will be responsible for the end-to-end administration of Tenable SecurityCenter (Tenable.sc) / Tenable Vulnerability Management and Nessus scanners across multi-enclave operational networks.
Responsibilities
Key Responsibilities
1. System Administration & Infrastructure Management
Deploy, configure, patch, and maintain Tenable.sc (SecurityCenter), Nessus Network Monitors (NNM), and distributed Nessus Scanners hosted primarily on Red Hat Enterprise Linux (RHEL) systems.
Manage scanner placement, firewall port requirements, and scanning zones to ensure uninterrupted, credentialed visibility across physical, virtual, and cloud assets.
Maintain system health, monitor disk space and database performance, and perform regular backups and disaster recovery validation of ACAS consoles and scanner repositories.
Implement software updates, plugin updates, and license renewals across all scanning components in accordance with operational schedules.
2. Vulnerability & Compliance Scanning
Create, schedule, and execute automated and ad-hoc credentialed network, database, and OS vulnerability scans across all designated IP subnets and enclaves.
Configure scan policies, audit files, and credentials (SSH keys, Windows service accounts, SNMP strings) to ensure high scan success rates and low scan failure/unauthenticated scan ratios.
Perform DISA Security Technical Implementation Guide (STIG) compliance audits and SCAP (Security Content Automation Protocol) benchmarks using ACAS.
3. Analysis, Reporting & Documentation
Analyze raw vulnerability scan outputs, filtering false positives and correlating scan findings with Common Vulnerabilities and Exposures (CVE) / National Vulnerability Database (NVD) records.
Generate tailored risk assessment dashboards, trend analysis reports, and executive summary briefings for leadership and system owners.
Export and format vulnerability data for ingestion into tracking portals (e.g., eMASS, VRAM, Archer, Jira, or ServiceNow).
Assist system owners and ISSOs in formulating Plans of Action and Milestones (POA&Ms) and preparing risk-acceptance justification packages.
4. Remediation Support & Collaboration
Collaborate with Windows, Linux, and network infrastructure teams to communicate critical vulnerability disclosures, patch advisories (IAVAs, IAVBs, CTOs), and remediation priorities.
Perform post-remediation verification scans to confirm vulnerability mitigations and update repository baselines.
Participate in incident response, technical security audits, and command Cyber Security Inspection (CCRI) preparation.
Qualifications
Required
Secret Clearance
• Experience implementing and managing DoD RMF for classified and unclassified systems.
• Working knowledge of:
○ NIST SP 800-53 Rev. 5
○ eMASS
○ POA&M management
○ ATO / Authorization processes
○ ACAS tool
• At least one active Department of Defense 8140/ DCWF IAT/IAM Level III certification (e.g.,
CASP+CE, CCNP Security, CISA, CISSP, GCED, GCIH, CCSP, CISM, GSLC, CCISO).
• Understanding of system controls and their impact on system security.
• Minimum of 5 years monitoring system NIST compliance using workflow
tools.
• Minimum of 3 years using…