Introduction:
In the ever-evolving landscape of cybersecurity evolution, the traditional approach of relying solely on perimeter defenses is no longer sufficient. The emergence of sophisticated threats and the diminishing effectiveness of traditional perimeters have paved the way for innovative strategies. Two prominent methodologies that have gained traction are Defense in Depth and Zero Trust, both crucial components of the evolving DevSecOps practices.
Defense in Depth: A Layered Approach
Defense in Depth, rooted in a military strategy, takes a layered approach to security, recognizing the need for protection at every level of operations and infrastructure. The National Institute of Standards and Technology (NIST) defines Defense in Depth as an “information security strategy integrating people, technology, and operations capabilities to establish variable barriers across multiple layers and dimensions of the organization.”
This approach originated from the military’s defensive strategy, aiming to protect the population while preserving the effectiveness of defense installations.In the context of cybersecurity evolution, Defense in Depth acknowledges the deterioration or even absence of a perimeter, requiring defense measures at various layers. The layers, illustrated in Figure, include Perimeter, Network, Host, Application, and Data.
Figure : Layered Security: Defense in Depth
Each layer of cybersecurity evolution demands different security measures, encompassing physical and technical boundaries, network security, application security, and data protection. Perimeter security involves physical and technical defenses, while network security includes measures such as firewalls and virtual private networks. Application security focuses on securing technical applications and services, incorporating vulnerability scanners and software composition analysis. Data security involves safeguarding digital information through identity and access management, data classification, and encryption.
Operational and Governance Activities in Defense in Depth
Beyond technology solutions, Defense in Depth involves operational and governance activities. Telemetry, the measurement data collected by tools, facilitates 24/7 support and response. Governance functions ensure compliance with regulations and effective tool operation. The collaboration between operations, governance, and application development teams is crucial in a DevSecOps approach, discouraging the formation of separate silos.
As the traditional perimeter disintegrates, Defense in Depth emphasizes the importance of multifaceted protection, encompassing technology, people, and operations across all layers of the system.
Zero Trust: Never Trust, Always Verify
Zero Trust, another response to contemporary cybersecurity challenges, revolves around the principle of “never trust, always verify.” This approach, as defined by NIST, is a security concept centered on the belief that organizations should not automatically trust anything inside or outside their perimeters and must verify any connection attempt.
Initially coined by Stephen Paul Marsh in 1994, the concept gained momentum with Google’s implementation of a Zero Trust architecture called BeyondCorp in 2009. BeyondCorp focused on access policies based on device, device state, and user attributes. Zero Trust doesn’t merely rely on Defense in Depth but asserts that trust should never be assumed, even with multiple layers of defense.
Five Pillars of Zero Trust
The Cybersecurity & Infrastructure Security Agency (CISA) defines the five pillars of Zero Trust as Identity, Device, Network/Environment, Application Workload, and Data. Identity involves unique recognition attributes, emphasizing least privilege access. Device security ensures both user identity validation and device security. Network protections include segmentation and micro-segmentation, along with encryption and threat protection. Application workload protection involves continuous authorization, behavioral analysis, and integrated security testing. Data protection includes tagging, encryption, and strict access controls.
Challenges and Misuse of Terminology
While Defense in Depth and Zero Trust provide valuable security models, their terminologies have often been co opted as marketing buzzwords. Products marketed as “Zero Trust Solutions” can contribute to confusion, as these concepts require holistic implementation and cannot be addressed by a single product or service.
Shift Left: Testing and Security Engineering
Shift Left, originating in testing methodologies, is a concept crucial to DevSecOps. It involves performing tasks earlier in the development process, reducing the time and effort required to address defects. The cost of fixing defects grows substantially through later stages of development, emphasizing the importance of addressing issues early.
Shifting left not only applies to testing but also to reliability and security engineering practices. By integrating security testing earlier in the development cycle, the familiarity of developers with the code enhances remediation efficiency. This aligns with DevOps principles, particularly the First and Second Ways of DevOps, promoting increased flow of value and shortened feedback loops.
The Cost of Technical Debt and Shift Left Benefits
The delay in defect removal, particularly security vulnerabilities, results in increased technical debt. Research from the 1990s and early 2000s emphasized the significant cost difference between fixing defects at the requirements phase versus in production. Shift Left addresses this by incorporating security earlier in the development process, reducing costs, and mitigating risks associated with legacy systems.
Smearing Left: Early Task Execution
Smearing left, a term coined by Dave Stanke, goes beyond merely shifting tasks earlier; it involves executing tasks as early as possible. For security, smearing left means addressing smaller sections of security concerns earlier in the development life cycle.
Shift Right: Testing in Production
Shift Right complements Shift Left by focusing on increasing testing further to the right in the development life cycle, even testing in production. With the complexity of modern systems, testing in pre production or “production-like” environments is often insufficient. Practices like Chaos Testing, A/B testing, and canary releases allow for testing in real-world conditions, enhancing resilience and ensuring quality.
DevSecOps and the Role of Shift Left
Shift Left is fundamental to DevSecOps, aligning with the core concept that security is everyone’s responsibility. It integrates security into every step of the development process, reducing feedback loops and lowering the cost to address defects. DevSecOps, with its emphasis on continuous integration and deployment, accelerates the applicability of Shift Left practices.
Conclusion: Embracing Zero Trust in the DevSecOps Paradigm
In conclusion, the cybersecurity landscape demands continuous evolution in response to emerging threats. The adoption of Zero Trust principles within the DevSecOps paradigm exemplifies a proactive and holistic approach to security. By integrating security from the outset, organizations can not only enhance their resilience but also deliver secure and innovative solutions at the speed demanded by today’s digital landscape. Embracing Zero Trust, coupled with the principles of Defense in Depth and the practices of Shift Left and Shift Right, forms a robust foundation for securing the modern enterprise.
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