Each scanner class reads a different input and finds a different kind of problem. SAST reads your source code, SCA reads your dependencies, secrets scanning reads files and history for credentials, container scanning reads image contents, IaC scanning reads infrastructure definitions, and CSPM reads live cloud configuration.
The one question that sorts them
Ask what the tool looks at. The input decides the findings.
| Class | Reads | Typically finds |
|---|---|---|
| SAST | Source code | Injection patterns, unsafe function use |
| SCA | Manifests and lockfiles | Known vulnerable libraries, licences |
| Secrets scanning | Files, commits, history | Keys, tokens, passwords in plain text |
| Container scanning | Image layers | Vulnerable OS and app packages, embedded secrets |
| IaC scanning | Terraform, Kubernetes, Dockerfiles | Risky settings before deploy |
| CSPM | Cloud provider configuration | Drift and exposure in what is actually running |
What each one is good at
SAST looks for flaw patterns in code your team wrote. OWASP notes that these tools scale well, run repeatedly in CI, and point to a file and line. SCA matches the components you use against known vulnerability records. Secrets scanning looks for credential shapes. Container scanning inspects what shipped inside an image, including packages your lockfile never mentioned. IaC scanning reads the plan for a cloud environment, so a public bucket can be caught in a pull request. CSPM checks the environment as it exists now, including changes someone made by hand in a console.
What each one cannot see
The limits matter more than the strengths.
- SAST does not know which libraries you pulled in, and OWASP lists high false positive rates and weak coverage of authentication and access control problems.
- SCA does not see your own logic bugs. It also depends on matching a component to a record, which can miss components that are hard to identify.
- Secrets scanning finds credentials that look like credentials. A custom token format may slip through unless you add a rule.
- Container scanning covers packages it can recognise. Software compiled in by hand may not be listed.
- IaC scanning checks the definition, not reality. Anything created outside the code is invisible to it.
- CSPM sees the running configuration but not the code that produced it, so fixes land in the wrong place unless they are traced back.
Overlap is normal
Tools overlap on purpose in a few places. SCA and container scanning both report vulnerable packages. IaC scanning and CSPM both report risky settings. Secrets scanning and container scanning can both find a key. Overlap is useful when it gives you a second chance to catch the same mistake at a different stage, and wasteful when two tools raise the same ticket twice. See how to deduplicate findings across scanners for the second case.
Where Safeguard fits
Safeguard covers SBOM and dependency scanning, reachability analysis to show which vulnerable code is actually called, and policy gates that can block a change. You can try a free scan on a project to see the SCA side.
Quick check
Which class finds a public storage bucket created by hand in a console?
CSPM. IaC scanning only sees what is defined in code, so a manual change never passes through it.
Does SCA replace SAST?
No. SCA covers libraries you import. SAST covers code you wrote. They read different inputs.
Sources
Last reviewed: 19 October 2026.
