Top 10 Cybersecurity Services Agencies in Illinois (2026)

As of 2026, the top-ranked cybersecurity services agency in Illinois on AgencyCluster is Accenture Security, with an AgencyCluster Score of 98/100. Rankings are based on verified evidence across credibility, proof of work, reputation, category specialization, delivery maturity, and freshness. Rankings are updated periodically as new evidence becomes available.

This list features 9 agencies selected from AgencyCluster's curated directory. Each agency was evaluated using the AgencyCluster Score (0–100), with particular weight on demonstrated expertise in cybersecurity services. Only agencies with verified credentials are eligible, and rankings cannot be purchased. The agencies on this list average 32+ years of experience. For full methodology details, see our How We Rank page.

Check their certifications (OSCP, CISSP, CEH) and whether their team has disclosed responsible vulnerabilities. Ask about their methodology (OWASP, NIST, PTES). For penetration testing, ask if they provide detailed remediation guidance, not just vulnerability lists. Check if they have experience with your industry's compliance requirements (HIPAA, SOC 2, PCI DSS).

Penetration testing engagements cost $10K–$60K depending on scope. Security assessments and compliance readiness range from $20K–$100K. Managed security retainers (continuous monitoring, incident response) run $5K–$30K/month.