Docker Images: Kicking the Tires of Docker Scout

I never moved away from Docker Desktop. For some time, after you use it to build an image, it prints a message:

What's Next?
  View a summary of image vulnerabilities and recommendations → docker scout quickview

I decided to give it a try. I'll use the root commit of my OpenTelemetry tracing demo. Let's execute the proposed command:

docker scout quickview otel-catalog:1.0

Here's the result:

    ✓ Image stored for indexing
    ✓ Indexed 272 packages
  Target               │  otel-catalog:1.0        │    0C     2H    15M    23L
    digest             │  7adfce68062e            │
  Base image           │  eclipse-temurin:21-jre  │    0C     0H    15M    23L
  Refreshed base image │  eclipse-temurin:21-jre  │    0C     0H    15M    23L
                       │                          │
What's Next?
  View vulnerabilities → docker scout cves otel-catalog:1.0
  View base image update recommendations → docker scout recommendations otel-catalog:1.0
  Include policy results in your quickview by supplying an organization → docker scout quickview otel-catalog:1.0 --org <organization>

Docker gives out exciting bits of information:

• The base image contains 15 middle-severity vulnerabilities and 23 low-severity ones
• The final image has an additional two high-level severity
• Ergo, our code introduced them!

Following Scout's suggestion, we can drill down the CVEs:

docker scout cves otel-catalog:1.0

This is the result:

    ✓ SBOM of image already cached, 272 packages indexed
    ✗ Detected 18 vulnerable packages with a total of 39 vulnerabilities
## Overview
                    │       Analyzed Image
────────────────────┼──────────────────────────────
  Target            │  otel-catalog:1.0
    digest          │  7adfce68062e
    platform        │ linux/arm64
    vulnerabilities │    0C     2H    15M    23L
    size            │ 160 MB
    packages        │ 272
## Packages and Vulnerabilities
   0C     1H     0M     0L  org.yaml/snakeyaml 1.33
pkg:maven/org.yaml/[email protected]
    ✗ HIGH CVE-2022-1471 [Improper Input Validation]
      https://scout.docker.com/v/CVE-2022-1471
      Affected range : <=1.33
      Fixed version  : 2.0
      CVSS Score     : 8.3
      CVSS Vector    : CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:L
   0C     1H     0M     0L  io.netty/netty-handler 4.1.100.Final
pkg:maven/io.netty/[email protected]
    ✗ HIGH CVE-2023-4586 [OWASP Top Ten 2017 Category A9 - Using Components with Known Vulnerabilities]
      https://scout.docker.com/v/CVE-2023-4586
      Affected range : >=4.1.0
                     : <5.0.0
      Fixed version  : not fixed
      CVSS Score     : 7.4
      CVSS Vector    : CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N

The original output is much longer, but I stopped at the exciting bit: the two high-severity CVEs. First, we see the one coming from Netty still needs to be fixed - tough luck. However, Snake YAML fixed its CVE from version 2.0 onward.

I'm not using Snake YAML directly; it's a Spring dependency brought by Spring. Because of this, no guarantee exists that a major version upgrade will be compatible. But we can surely try. Let's bump the dependency to the latest version:

<dependency>
    <groupId>org.yaml</groupId>
    <artifactId>snakeyaml</artifactId>
    <version>2.2</version>
</dependency>

We can build the image again and check that it still works. Fortunately, it does. We can execute the process again:

docker scout quickview otel-catalog:1.0

Lo and behold, the high-severity CVE is no more!

    ✓ Image stored for indexing
    ✓ Indexed 273 packages
  Target     │  local://otel-catalog:1.0-1  │    0C     1H    15M    23L
    digest   │  9ddc31cdd304                │
  Base image │  eclipse-temurin:21-jre      │    0C     0H    15M    23L

Conclusion

In this short post, we tried Docker Scout, the Docker image vulnerability detection tool. Thanks to it, we removed one high-level CVE we introduced in the code.

To go further:

• Docker Scout
• 4 Free, Easy-To-Use Tools For Docker Vulnerability Scanning

Also published here.