How to build an application security program

Laying the application security program foundations

With clear objectives and a maturity assessment in hand, building a successful AppSec program requires three foundational elements that set the stage for all subsequent security activities: leadership buy-in and cross-functional collaboration, security by design and threat modeling.

Leadership buy-in and cross-functional collaboration

Success begins with getting the right people involved. Executive sponsorship ensures proper resource allocation and program visibility. Create a steering committee with representatives from development, operations, security, compliance and business units. This diverse perspective helps align security objectives with business goals and ensures the practical implementation of security measures.

Security by design

Shifting left -- rather than treating security as an afterthought -- means integrating it into the earliest stages of application development. This shift-left approach means implementing security controls during the design and development phases of the software development lifecycle (SDLC). Establish secure coding guidelines, conduct architecture reviews and integrate security requirements into user stories and acceptance criteria.

Threat modeling

Threat modeling is a cornerstone of effective application security. It systematically identifies potential threats and vulnerabilities early in the SDLC. By bringing together developers, architects and security professionals to analyze application components and data flows, threat modeling builds security awareness while fostering valuable cross-team collaboration. The resulting insights directly inform security requirements and architectural decisions, enhancing the effectiveness of all other AppSec activities.

6 core elements of an AppSec program

A comprehensive application security program requires specific operational components and tools strategically deployed across the SDLC to identify vulnerabilities, enforce standards, raise security awareness among developers and respond to emerging threats.

Software bills of materials

Maintain detailed software bills of materials (SBOMs) for all applications to track components, dependencies and their associated vulnerabilities. This inventory becomes crucial for the following:

• Rapid response to newly discovered vulnerabilities.
• License compliance management.
• Supply chain risk assessment.
• Efficient security patch management.

Software testing strategy

Implement a multilayered testing approach that includes the following:

• Static application security testing (SAST) to analyze source code.
• Dynamic application security testing (DAST) to identify runtime vulnerabilities.
• API security testing to protect critical application interfaces.
• Interactive application security testing (IAST) for real-time analysis.
• Software composition analysis (SCA) to manage third-party components.
• Regular penetration testing by qualified security professionals.

The best approach is to start with SAST and API testing, supplemented with a regular pen testing regime to cover regulatory requirements. As the program matures, broaden this approach to include other testing, such as IAST, SCA and DAST, to provide the broadest coverage.

Cloud testing and protection strategy

Protect cloud workloads using the following:

• Cloud-native application protection platforms to secure cloud-native applications and infrastructure.
• Cloud security posture management to continuously monitor cloud environments for misconfigurations and compliance violations.
• Cloud workload protection platforms to secure containers, serverless functions and VMs.

Documentation and standards

Create clear, accessible documentation that outlines the following:

• Security requirements and controls.
• Secure coding guidelines.
• Security testing procedures.
• Incident response protocols.
• Compliance requirements and controls mapping.
• Risk acceptance criteria.

Make these documents living artifacts by regularly reviewing and updating them to reflect new threats and organizational changes.

Security awareness and training

Develop a comprehensive training program that includes the following:

• Secure coding practices for developers.
• Security awareness for all stakeholders.
• Role-specific security training.
• Regular updates on new threats and mitigation strategies.
• Hands-on workshops and practical exercises.

Security champions

Embed security-minded individuals within development teams to serve as liaisons with the security team to do the following:

• Provide team-specific security guidance and help translate requirements into technical implementations.
• Distribute security knowledge and responsibility across the organization.
• Reduce bottlenecks by addressing common security questions at the team level.
• Foster a culture where security is integrated into the development process.

Scale the AppSec program through integration and automation

To achieve scale and consistency, an application security program must seamlessly integrate with development workflows while establishing formal risk management and incident response processes that maintain security without impeding delivery.

Integration with DevOps

Use the following to ensure security tools and processes integrate seamlessly with the development pipeline to minimize friction and drive adoption:

• Automated security testing in continuous integration/continuous delivery pipelines.
• Security policy as code.
• Automated compliance checks.
• Infrastructure-as-code security scanning.
• Container security scanning.

Risk management and compliance

Establish a risk management framework that does the following:

• Identifies and categorizes application risks.
• Defines risk acceptance criteria.
• Maps security controls to compliance requirements.
• Maintains audit trails.
• Provides regular risk reporting to stakeholders.

Incident response and recovery

Develop and document procedures for the following:

• Security incident detection and response.
• Vulnerability management and patching.
• Emergency code changes.
• Post-incident analysis and lessons learned.
• Communication protocols during security events.

Tracking an AppSec program's progress

The final step is to ensure continuous monitoring and improvement of the program to align with the primary driver from the initial question: "What are we trying to achieve?"

Implement the following metrics to measure program effectiveness:

• Security testing coverage.
• Vulnerability remediation times.
• Security debt trends.
• Incident response effectiveness.
• Compliance audit results.

Use automatically generated metrics to identify areas for improvement, and adjust the program accordingly.

A successful AppSec program requires clear objectives, a realistic assessment of organizational maturity and strategic implementation of core security components. By integrating security controls throughout the SDLC, establishing cross-functional collaboration and measuring meaningful metrics aligned with business goals, organizations can effectively protect their applications while enabling innovation. In today's sophisticated threat landscape, this structured approach transforms security from an obstacle to a competitive advantage.

Colin Domoney is a software security consultant who evangelizes DevSecOps and helps developers secure their software. He previously worked for Veracode and 42Crunch and authored a book on API security. He is currently a CTO and co-founder, and an independent security consultant.