Attack surface reduction: Practical strategies to minimize risk

Cloud-native stacks move fast and accumulate sprawling dependencies even faster. Services appear and disappear, old ones become stale, and their configurations drift. You can’t rely on security tools to keep up, since security tools focus on reporting and detection, not triage. Their output of alerts you have to consider or address grows just as fast as your system’s complexity.

Attack surface reduction (ASR) restructures the flow of security scanning and problem detection. It establishes hard limits on the components, privileges, and vulnerable paths that need to be scanned. When done well, ASR gives engineering teams a smaller, more predictable footprint to defend, and bounds on the effort required to protect against and repair security issues. The sections ahead focus on effective techniques for reducing the attack surface.

What is Attack Surface Reduction (ASR)?

ASR is a security discipline that ruthlessly focuses on reducing and limiting what attackers can reach, use, or take advantage of. When you implement ASR, you make your systems simpler, remove unnecessary components, tighten privileges, and collapse dependency graphs so fewer paths remain available for exploitation.

A related technique is Attack Surface Management (ASM). ASM is applied more at the operational end of the pipeline, where you aim to be efficient in detecting, discovering, and monitoring potential vulnerabilities and attack opportunities (see the table below for more details). By contrast, ASR applies at the structural end: it’s more about changing your upfront design and architecture choices. You’ll use it to focus your components, turning them into clear and secure building blocks for your system. Unlike for ASM, ASR has little to do with security monitoring dashboards. When teams apply it consistently, especially within the software supply chain, they lower risks and eliminate entire classes of problems before scanners or auditors enter the picture.

Why attack surface reduction matters more than ever

Modern attack surfaces are expanding exponentially, driven by AI-powered, automated tools that produce and manage software systems. The most sustainable way you can stay secure in the face of this rate of change is to reduce your attack surfaces. You reduce your vulnerability exposure at the source and limit the effort required to detect and remediate problems after deployment.

Cloud-native growth has multiplied every potential entry point

Every new service, API, container image, and ephemeral environment adds to your attackable surface area. Microservices increase the number of lateral movement paths, and misconfigurations and drift compound over time. Infrastructure-as-code efforts, along with per-service pods and environments, allow you to quickly create massive infrastructure. While it’s easy to build fast and big, traditional inventory and scanning pipelines won’t stay accurate with this rate of change.

The software supply chain has become the new frontline of risk

Most exposure now comes not from what your teams have built, but what they are building on. Third-party libraries, base images, transitive dependencies, and upstream automation are now shared across many major projects, making them attractive targets for attackers since vulnerabilities introduced this far back in the build process have outsized impacts. With these dependencies, a steady flow of risks accumulates in your system before it ever reaches production.

Unless intentionally managed and controlled, this layer will continue to expand. Security and engineering teams will absorb dependency growth as a backlog of CVEs and issues to address.

AI and automation are expanding exposure faster than security can react

AI tooling dramatically increases output, resulting in more code, artifacts, and services. With this kind of automation, you’ll accelerate deployment, but you’ll also accelerate misconfiguration rates, vulnerability rates, and dependency churn. Your security team inherits this growth curve.

Common causes of attack surface expansion

If you follow the headlines, you’ll come away with the impression that attack surfaces expand due to esoteric, one-off mistakes. They don't; they expand as a result of intentional structural and architectural decisions. And those decisions then allow mistakes to become vulnerabilities: the larger the attack surface, the easier it is for mistakes to become exploitable. This surface expansion, for most teams, follows a few core patterns: more components, more identities, more dependencies, and more drift than their security systems and workflows can absorb.

Rapid infrastructure growth and configuration drift

Kubernetes clusters, serverless functions, and autoscaling fleets create a constant system churn. Infrastructure as Code (IaC) templates spread defaults broadly, allowing configuration drift to accumulate long before audits or scans are scheduled against them.

Over-permissioned identities and inconsistent access controls

Identity sprawl grows quietly: you might create extra roles for development, wide-scope policies “temporarily” have an admin account “just for one debug session in prod”, and launch CI runners with elevated access. Service accounts, CI jobs, and automation pipelines often default to broad privileges. These access paths persist because it’s hard to remember to revert short-term permissions and difficult to remove later (you never know if someone still needs that one extra permission somewhere), and so they create long-lived risk.

Unpatched systems and outdated dependencies

Dependency graphs grow exponentially, and there are only so many patch cycles you can execute a month. Many base images and libraries introduce vulnerabilities immediately on inclusion. Teams often inherit these invisible issues from upstream and integrate them into systems before code reaches production. Maintenance work is often slow, time-consuming, and thankless, so it doesn’t always receive the attention and priority it deserves.

Third-party and open-source component risks

Applications now ship with deep dependency chains. A single library pulls in dozens more, each with its own vulnerabilities and update cycle. Each of these dependencies extends your attack surface. So most of the attack surface exists in code that your developers don’t write, never see, and often don’t even know exists in their systems.

Tool sprawl and integration gaps across teams

There’s no single security tool or service that can scan for and help catch vulnerabilities across all of these surfaces. So security and platform teams accumulate scanners, posture tools, and workflow systems, each specialised in managing some portion of the attack surface. These tools usually don’t integrate very well with each other. And each one is, technically, another component of your architecture and infrastructure. They add agents, configurations, and permissions, thereby increasing the attack surface, not to mention a great deal of often-overlapping alert noise.

8 practical strategies to reduce your attack surface

The farther left you can move the work to shrink attack surfaces, the more effective it becomes. These strategies highlight some of the controls you can implement, focusing on reducing what exists, tightening what’s allowed, and removing unnecessary components and complexity as early as possible before your systems get to production. These ASR techniques are particularly effective blends of developer-centric and IT hygiene practices.

1. Maintain a strong patching and update cadence

The fastest way to shrink exposure is to minimize the time vulnerabilities remain in the environment. Automated rebuilds and patch workflows prevent backlogs and maintain dependency freshness. Teams with consistent update pipelines confront less remediation toil and fewer long-lived CVEs.

2. Enforce least-privilege access across systems

Reduce every identity—human or machine—to the smallest set of permissions required. Tight privileges limit lateral movement and simplify incident response. Regularly review access, set expirations on all credentials (and keep the expirations as short as possible), scope service accounts correctly, and rotate access keys regularly. Keep your privilege list contained.

3. Use minimal, secure-by-default base images and dependencies

Make sure you only include the components you actually depend on. Minimal base images remove entire categories of packages, thereby reducing the volume of CVEs and configuration exposure. This is one of the highest-impact levers because it eliminates vulnerabilities before scanners ever detect them. Crucially, it also helps you avoid launching systems you don’t need or use in production (a source of the hardest-to-detect and remediate vulnerabilities, since they’re in systems you don’t know to look at or scan for).

4. Remove or disable unnecessary services and accounts

Unused ports, daemons, debugging tools, and abandoned identities accumulate over time. Whenever possible, make sure they automatically expire. Intentionally tracking, auditing, and eliminating them reduces the reachable surface area and shrinks the blast radius of misconfigurations.

5. Continuously verify and rebuild components from source

Frequent rebuilds ensure images stay current with upstream patches and reduce exposure from stale dependencies. Automated rebuild systems catch issues early and prevent configuration drift across environments. They also reduce the amount of time each version of each component spends in production, one of the most sure predictors of security incidents and vulnerability exposure.

6. Harden CI/CD pipelines and isolate build environments

Securing the build system prevents supply-chain compromise. Isolation, reproducible builds, scoped secrets, and strict runner permissions keep the most sensitive part of the stack protected.

7. Standardize tooling to reduce complexity and human error

A coherent toolchain reduces misaligned workflows and the operational variance that leads to blind spots. Teams using shared, integrated systems move faster and introduce fewer security regressions.

8. Embed attack surface reduction into developer workflows

The most left you could move is into developer workflows. Integrate security constraints at the point of creation so surfaces are reduced by default. You’ll avoid costly and time-consuming manual cleanups after deployment. Templates, base images, policy checks, and automated pipelines: embed a security focus into all of these to consistently bring a security surface reduction-oriented bias into your development flows.

Tools and technologies that support Attack Surface Reduction

Any tool or technology you include will add some agents, dashboards, and configuration load to your systems. This can, ironically, increase your attack surface, so the ideal toolset should compensate for the surface growth by being well-integrated, easy to consolidate, and eliminating unnecessary work. They should reduce the need for redundant components and promote predictability, focusing on automation, integration, and upstream prevention.

Continuous vulnerability scanners and configuration management tools

Scanners can help you identify exposure early, and configuration tools keep systems aligned to your declared intent. In this context, they work best when tied to earlier parts of your flows. For example, you can run them as part of automated rebuilds or deployment pipelines, where they are well-integrated into your CI and build outputs.

SBOMs and provenance tools for supply chain visibility

Detailed software bills of materials and signed provenance records make dependencies programatically traceable. This visibility allows you to automate triage, have cleaner audits, and reduce blind spots caused by transitive dependencies. These are some of the most effective tools for managing complexity sprawl for your infrastructure.

Container and dependency management platforms

Platforms that start from minimal, hardened images and continuously rebuild dependencies shrink the footprint at the source. They can prevent vulnerability accumulation throughout your pipelines and infrastructure, since you know you’re using secure base components throughout.

Access governance and identity management solutions

Strong IAM controls enforce least privilege and reduce lateral movement paths. Automated access reviews and role-scoped service accounts help you contain identity sprawl. Permission and account expirations, as well as regularly automated rotation of access keys, all help reduce the potential attack surface and contain any hypothetical breach.

Policy-as-code and infrastructure security automation

Codified guardrails prevent insecure configurations from reaching production. When integrated with CI/CD, these tools will automatically enforce system simplicity and reduction throughout your templates and pipelines. They will keep your surface area from growing, and can raise alarms if it ever crosses troubling thresholds.

Measuring and maintaining a reduced attack surface

How do you know if you’re successfully reducing your attack surface? You’ll want to keep track of both direct metrics and additional signals that strongly correlate with the size of your attack surface. Specifics will depend on how your system is configured and can be tailored to your goals. We’ve listed some common examples of metrics to track in the table below:

Once you can measure whether the surface is shrinking or drifting, the next step is addressing the root cause: how software is built and shipped in the first place.

How Chainguard simplifies attack surface reduction in the software supply chain

The most effective ways to reduce your attack surface are within the software supply chain. Images, packages, and build systems account for the majority of inherited risk, and eliminating unnecessary components at this layer prevents vulnerabilities from entering your environment in the first place.

Chainguard is built around three principles that drive meaningful surface reduction:

• Secure-by-default design: minimal, hardened artifacts with fewer components to attack.

• Automation at scale: continuous rebuilds and automated remediation.

• Seamless workflow integration: improvements delivered without disrupting developer velocity.

These principles translate into immediately useful and relevant components and tools you can use:

• Minimal, hardened container and VM images: use fewer packages, contain fewer CVEs, and limit the blast radius in the event of an issue.

• Continuously rebuilt artifacts from source: daily updates eliminate stale dependencies and reduce exposure time. They will reduce all of your exposure metrics.

• SBOMs and provenance metadata: bring verifiable transparency into every component. Know how and when each item was built, making it easier to track your SAR metrics, monitor your system’s health, and quickly react to any potential incident.

• SLA-backed patching timelines: you can count on predictable, fast remediation of critical and high-severity issues, which you can transparently fold into your daily build and CI pipelines.

• Developer-friendly integration: integrates into existing CI pipelines, artifact registries, and scanners without workflow changes.

Talk to an expert to see how these reductions can apply directly to your environment.