Source based scanning reads your code and dependencies, agentless scanning reads cloud and image data through APIs, and agent based scanning runs software on each host. Each sees a different layer. Pick by where your risk sits, and expect to combine two of them for full coverage.
Source based: code and dependencies
This approach reads manifests, lockfiles and source in your repositories or build. It finds vulnerable libraries before they ship and can tie a finding to a pull request and an owner. It cannot see what only exists at runtime, such as a package installed by an operations script or a host setting.
Agentless: read the environment through APIs
Agentless tools read cloud configuration, container registries and snapshots. Rollout is fast, because nothing is installed on hosts. Depth is limited to what the API exposes, and a snapshot can be hours old.
Agent based: software on every host
An agent sees running processes, installed packages and local configuration in near real time. The cost is deployment, upgrades, performance overhead and coverage drift when a host is built without it. Ephemeral workloads make this harder.
Match the approach to the risk
If your main exposure is open source libraries in applications you build, source based scanning covers the most ground per hour of effort. If you run many long lived servers, host visibility matters more. If most of your estate is containers, scan images in the registry and at build.
Questions that separate good fits
What does this approach not see? How current is its data? What is the rollout effort per team? What happens to coverage when an asset is created tomorrow without anyone telling security?
Combining them sensibly
Many programs pair source based scanning for what they build with agentless reads for what they run. The pairing only works if findings land in one place with one owner model, otherwise you double the noise.
A short worked example: a company with forty services built from its own repositories, deployed as containers to one cloud. Source scanning of the repositories plus image scanning in the registry covers most of what it ships. Host agents would add little for containers that live a few hours, while an agentless read of cloud configuration would add a separate view of exposure.
Where Safeguard fits
Safeguard covers SBOM and dependency scanning, reachability analysis, policies and gates, and fix pull requests that stay off until you turn them on. You can try a free scan on a repository before you commit to anything.
Try it yourself
Scan the sample image and look at which layers and packages are reported, then think about what a source scan would not have shown.
Click through it at your own pace, or open it full screen.
Quick check
Do I need all three?
Rarely. Start with the layer where most of your exposure sits and add a second when gaps appear.
Is agentless less accurate?
Not always, but it sees less detail and may lag. Check data freshness.
Last reviewed: 19 October 2026.
