Security Testing: Pentesting, SAST, DAST, and Scanning
Security testing is the systematic evaluation of software, systems, and networks to identify vulnerabilities before attackers do. The 2025 Synopsys Software Security Report found that organizations conducting regular security testing remediate vulnerabilities 6x faster and spend 35% less on post-production incident response. This guide covers the full spectrum of security testing methodologies — penetration testing, SAST, DAST, vulnerability scanning, and security auditing — with practical guidance for building a comprehensive testing program.
Penetration Testing Methodology
Penetration testing simulates real-world attacks to identify exploitable vulnerabilities. Unlike automated scanning, pen testing involves manual creativity, chaining multiple low-severity findings into critical exploit paths.
The PTES Framework
The Penetration Testing Execution Standard (PTES) defines seven phases: Pre-engagement Interactions, Intelligence Gathering, Threat Modeling, Vulnerability Analysis, Exploitation, Post-Exploitation, and Reporting. Each phase has deliverables documented in the PTES technical guidelines.
Intelligence Gathering
Reconnaissance gathers information about the target: DNS enumeration (dig, nslookup, dnsrecon), subdomain discovery (Sublist3r, Amass), email harvesting (theHarvester), technology fingerprinting (Wappalyzer, WhatWeb), and social media footprinting. Passive recon does not touch the target’s systems; active recon uses port scanning (Nmap, masscan) and service enumeration.
Vulnerability Analysis
Automated scanners (Nessus, OpenVAS, Qualys) identify known CVEs. Manual analysis verifies results, eliminates false positives, and identifies logic flaws that scanners miss. Critical analysis areas: authentication mechanisms (password policies, session management), authorization checks (IDOR, privilege escalation), injection points (SQLi, NoSQLi, command injection, SSTI), and cryptographic weaknesses.
Exploitation
Exploitation demonstrates impact. Metasploit provides exploit modules for known vulnerabilities. Manual exploitation tools include: SQLMap for SQL injection, John/Hashcat for password cracking, Responder for LLMNR/NBT-NS poisoning, and Impacket for Windows protocol exploitation. Responsible disclosure and safe exploitation practices require signed authorization letters and defined scope boundaries.
Post-Exploitation
Post-exploitation establishes persistence, enumerates lateral movement opportunities, escalates privileges, and extracts data samples to demonstrate business impact. Tools: Mimikatz for Windows credential extraction, BloodHound for Active Directory attack path mapping, Chisel for C2 tunneling.
Reporting
The penetration test report is the primary deliverable. It must include: executive summary (non-technical, business impact), technical findings (vulnerability description, reproduction steps, CVSS score, Mitre ATT&CK mapping), prioritized remediation recommendations, and retest scope/exclusions. The 2025 SANS Penetration Testing Best Practices guide emphasizes that actionable, prioritized remediation guidance determines the real value of a pentest.
SAST vs DAST
Static Application Security Testing (SAST) and Dynamic Application Security Testing (DAST) are complementary approaches that find different classes of vulnerabilities at different stages of the SDLC.
SAST — Static Analysis
SAST scans source code without execution. It finds vulnerabilities early — in the IDE or during PR review — when remediation is cheapest. SAST covers: SQL injection patterns (string concatenation in SQL queries), XSS patterns (unencoded user input in HTML output), hardcoded secrets, insecure deserialization, and cryptographic misuses. Tools: Semgrep (open-source, rule-based with OWASP coverage), SonarQube (language coverage with quality gates), Snyk Code (developer-friendly IDE integration), and Checkmarx (enterprise-grade).
SAST limitations: false positives (15-35% for most tools depending on tuning), limited ability to detect runtime issues (business logic flaws, authentication bypasses in complex flows), and processing time for large codebases.
DAST — Dynamic Analysis
DAST scans running applications, testing runtime behavior. It finds: configuration issues (exposed admin panels, default credentials), authentication weaknesses (session fixation, weak cookie attributes), input validation flaws that only appear at runtime, API misconfigurations (excessive data in responses, missing rate limiting), and business logic issues detectable through HTTP request manipulation.
DAST tools: OWASP ZAP (open-source, extensible via add-ons), Burp Suite Professional (industry standard for manual testing), HCL AppScan (enterprise DAST with automated crawling), and Qualys Web Application Scanner (cloud-based, continuous DAST).
Integrated SAST + DAST Program
Mature programs combine both: SAST at commit and PR time for immediate developer feedback, DAST against staging environments before production deployment, and periodic full-scope penetration testing. The 2025 BSIMM study found that organizations with both SAST and DAST programs achieve 73% faster vulnerability remediation than those with only one.
Vulnerability Scanning
Automated vulnerability scanning provides continuous coverage across the infrastructure attack surface.
Network Vulnerability Scanning
Nessus, Qualys, and OpenVAS scan network ranges for: open ports, running services, known CVEs with version detection, missing patches, weak SSL/TLS configurations (downgrade attacks, weak cipher suites), and SNMP community string exposure. Scans should run weekly for external infrastructure and monthly for internal networks.
Cloud Security Scanning
Cloud-native scanners (AWS Inspector, Azure Defender, GCP Security Scanner) evaluate EC2/ECR, VMs/ACR, and GCE/GCR for vulnerabilities. CSPM tools (Wiz, Prisma Cloud, Orca) extend coverage to: storage bucket permissions, IAM policy analysis, network exposure, and compliance drift detection.
Container Scanning
Container images accumulate vulnerabilities in base layers. Trivy, Grype, Anchore, and Docker Scout scan images against NVD, RedHat OVAL, Alpine secdb, and other databases. Scans must run at build time (blocking pipeline on critical CVEs), in registries (continuous monitoring), and at runtime (Kubernetes admission controller webhooks).
Security Audits
Security audits evaluate controls against established criteria. Types include: configuration audit (CIS Benchmarks for OS, database, cloud), compliance audit (SOC 2, ISO 27001, PCI DSS), code audit (manual review of critical code paths for business logic flaws), architecture audit (review of threat model and security design decisions).
Fuzzing and Bug Bounty Programs
Fuzzing — automated input generation to trigger unexpected behavior — has become a standard security testing technique for finding vulnerabilities that manual testing and static analysis miss.
Coverage-Guided Fuzzing
Coverage-guided fuzzers (libFuzzer, AFL++, Honggfuzz) instrument target code to track which code paths each input exercises. The fuzzer mutates inputs to maximize code coverage, automatically discovering edge cases. Google’s OSS-Fuzz program has found over 10,000 vulnerabilities in open-source software since 2016. Integration into CI/CD: run fuzzing continuously for critical libraries (parsers, decoders, serializers). Seed corpora should include valid inputs, edge cases, and known-malicious patterns. Fuzzing is most effective for: language parsers (JSON, XML, YAML), network protocol implementations, image/video decoders, and cryptographic libraries.
Bug Bounty Programs
Bug bounty programs incentivize external researchers to find and responsibly disclose vulnerabilities. HackerOne, Bugcrowd, and Intigriti host programs for organizations of all sizes. Key program elements: clear scope definition (in-scope assets and out-of-scope exclusions), severity-based reward tiers (critical $5,000-$50,000+, high $1,000-$5,000), response SLAs (first response within 24 hours, triage within 72 hours), and clear safe harbor and disclosure terms. The 2025 HackerOne Hacker Report found that programs with clear scope and fast payouts attract 4x more researcher engagement. For smaller organizations, private programs (invite-only) provide focused testing from vetted researchers without the noise of public submissions.
Coordinated Vulnerability Disclosure (CVD)
When vulnerabilities are found internally or reported by researchers, CVD provides a structured disclosure process. ISO 29147 and ISO 30111 define the CVD framework: receipt and acknowledgment, triage and investigation, remediation development, patch release, and public disclosure. The VINCE platform from CERT/CC provides a free CVD coordination tool. Disclosure timelines typically allow 90-120 days for remediation before public disclosure, with shorter timelines for actively exploited vulnerabilities.
Cloud and API Security Testing
Cloud environments and APIs present unique testing challenges requiring specialized approaches.
Cloud Security Testing
Cloud pentesting requires: provider authorization (AWS, Azure, GCP pre-approval), scope definition (accounts, regions, services in scope), and understanding of provider-specific attack paths (AWS IAM privilege escalation, GCP service account impersonation, Azure RBAC over-privilege). Tools: ScoutSuite (cloud auditing), Prowler (AWS benchmarks), CloudSploit (multi-cloud scanning), and Pacu (AWS exploitation). Common findings: over-permissive IAM roles, unencrypted storage buckets, exposed RDS instances, and missing VPC flow logs. The 2025 Cloud Security Alliance report found that 74% of cloud pentests discover at least one critical IAM misconfiguration.
API Security Testing
The OWASP API Security Top 10 (2023) includes: broken object-level authorization (BOLA), broken user authentication, excessive data exposure, and mass assignment. API testing tools: 42Crunch (API security audit), APISec (automated testing), and Postman with ZAP integration. GraphQL requires specific testing for: introspection queries, batching attacks, and depth/ complexity limit bypasses. REST APIs must be tested for IDOR in URL parameters, mass assignment in request bodies, and inconsistent authorization across endpoints.
FAQ
What is the difference between a vulnerability scan and a pen test? Vulnerability scans are automated checks for known CVEs. Penetration tests are manual, goals-based exercises that exploit vulnerabilities to demonstrate business impact. Both are complementary — scans for breadth, pentests for depth.
How often should I run security tests? SAST on every commit and PR. DAST on every staging deploy. Vulnerability scanning weekly. Full-scope penetration testing annually or on major architecture changes.
Which is better — SAST or DAST? Neither — they find different classes of bugs. SAST finds injection and cryptographic issues. DAST finds configuration, authentication, and runtime issues. Use both.
Do I need a penetration test if I have automated scanning? Yes. Automated scanners miss business logic flaws, multi-step attack chains, and zero-day vulnerabilities. Manual pentesting finds an average of 65% more critical vulnerabilities than automated scanning alone.
What should a pentest report include? Executive summary, detailed technical findings with CVSS scores and Mitre ATT&CK mappings, reproduction steps, prioritized remediation guidance, and retest scope.
For foundational security concepts, start with our Security Guide. Integrate testing into your pipeline with DevSecOps Guide. Proactively identify risks before testing with Threat Modeling.