Vulnerability scanning for Docker local images
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Vulnerability scanning for Docker local images allows developers and development teams to review the security state of the container images and take actions to fix issues identified during the scan, resulting in more secure deployments. Docker Scan runs on Snyk engine, providing users with visibility into the security posture of their local Dockerfiles and local images.
Users trigger vulnerability scans through the CLI, and use the CLI to view the scan results. The scan results contain a list of Common Vulnerabilities and Exposures (CVEs), the sources, such as OS packages and libraries, versions in which they were introduced, and a recommended fixed version (if available) to remediate the CVEs discovered.
Log4j 2 CVE-2021-44228
Versions of
docker Scanearlier thanv0.11.0are not able to detect Log4j 2 CVE-2021-44228. You must update your Docker Desktop installation to 4.3.1 or higher to fix this issue. For more information, see Scan images for Log4j 2 CVE.
For information about the system requirements to run vulnerability scanning, see Prerequisites.
This page contains information about the docker scan CLI command. For information about automatically scanning Docker images through Docker Hub, see Hub Vulnerability Scanning.
Scan images for Log4j 2 CVE
Docker Scan versions earlier than v0.11.0 do not detect Log4j 2 CVE-2021-44228 when you scan your images for vulnerabilities. You must update your Docker installation to the latest version to fix this issue.
If you are using the docker scan plugin shipped with Docker Desktop, update Docker Desktop to version 4.3.1 or higher. See the release notes for Mac and Windows for download information.
If you are using Linux, run the following command to manually install the latest version of docker scan:
On .deb based distros, such as Ubuntu and Debian:
$ apt-get update && apt-get install docker-scan-plugin
On rpm-based distros, such as CentOS or Fedora:
$ yum install docker-scan-plugin
Alternatively, you can manually download the docker scan binaries from the Docker Scan GitHub repository and install in the plugins directory.
Verify the docker scan version
After upgrading docker scan, verify you are running the latest version by running the following command:
$ docker scan --accept-license --version
Version: v0.12.0
Git commit: 1074dd0
Provider: Snyk (1.790.0 (standalone))
If your code output contains ORGAPACHELOGGINGLOG4J, it is likely that your code is affected by the Log4j 2 CVE-2021-44228 vulnerability. When you run the updated version of docker scan, you should also see a message in the output log similar to:
Upgrade org.apache.logging.log4j:[email protected] to org.apache.logging.log4j:[email protected] to fix
✗ Arbitrary Code Execution (new) [Critical Severity][https://snyk.io/vuln/SNYK-JAVA-ORGAPACHELOGGINGLOG4J-2314720] in org.apache.logging.log4j:[email protected]
introduced by org.apache.logging.log4j:[email protected]
For more information, read our blog post Apache Log4j 2 CVE-2021-44228.
How to scan images
The docker scan command allows you to scan existing Docker images using the image name or ID. For example, run the following command to scan the hello-world image:
$ docker scan hello-world
Testing hello-world...
Organization: docker-desktop-test
Package manager: linux
Project name: docker-image|hello-world
Docker image: hello-world
Licenses: enabled
✓ Tested 0 dependencies for known issues, no vulnerable paths found.
Note that we do not currently have vulnerability data for your image.
Get a detailed scan report
You can get a detailed scan report about a Docker image by providing the Dockerfile used to create the image. The syntax is docker scan --file PATH_TO_DOCKERFILE DOCKER_IMAGE.
For example, if you apply the option to the docker-scan test image, it displays the following result:
$ docker scan --file Dockerfile docker-scan:e2e
Testing docker-scan:e2e
...
✗ High severity vulnerability found in perl
Description: Integer Overflow or Wraparound
Info: https://snyk.io/vuln/SNYK-DEBIAN10-PERL-570802
Introduced through: git@1:2.20.1-2+deb10u3, meta-common-packages@meta
From: git@1:2.20.1-2+deb10u3 > [email protected]
From: git@1:2.20.1-2+deb10u3 > [email protected] > [email protected]
From: git@1:2.20.1-2+deb10u3 > [email protected] > perl/[email protected]
and 3 more...
Introduced by your base image (golang:1.14.6)
Organization: docker-desktop-test
Package manager: deb
Target file: Dockerfile
Project name: docker-image|99138c65ebc7
Docker image: 99138c65ebc7
Base image: golang:1.14.6
Licenses: enabled
Tested 200 dependencies for known issues, found 157 issues.
According to our scan, you are currently using the most secure version of the selected base image
Excluding the base image
When using docker scan with the --file flag, you can also add the --exclude-base tag. This excludes the base image (specified in the Dockerfile using the FROM directive) vulnerabilities from your report. For example:
$ docker scan --file Dockerfile --exclude-base docker-scan:e2e
Testing docker-scan:e2e
...
✗ Medium severity vulnerability found in libidn2/libidn2-0
Description: Improper Input Validation
Info: https://snyk.io/vuln/SNYK-DEBIAN10-LIBIDN2-474100
Introduced through: iputils/iputils-ping@3:20180629-2+deb10u1, [email protected], [email protected]+deb10u1, git@1:2.20.1-2+deb10u3
From: iputils/iputils-ping@3:20180629-2+deb10u1 > libidn2/[email protected]+deb10u1
From: [email protected] > libidn2/[email protected]+deb10u1
From: [email protected]+deb10u1 > curl/[email protected]+deb10u1 > libidn2/[email protected]+deb10u1
and 3 more...
Introduced in your Dockerfile by 'RUN apk add -U --no-cache wget tar'
Organization: docker-desktop-test
Package manager: deb
Target file: Dockerfile
Project name: docker-image|99138c65ebc7
Docker image: 99138c65ebc7
Base image: golang:1.14.6
Licenses: enabled
Tested 200 dependencies for known issues, found 16 issues.
Viewing the JSON output
You can also display the scan result as a JSON output by adding the --json flag to the command. For example:
$ docker scan --json hello-world
{
"vulnerabilities": [],
"ok": true,
"dependencyCount": 0,
"org": "docker-desktop-test",
"policy": "# Snyk (https://snyk.io) policy file, patches or ignores known vulnerabilities.\nversion: v1.19.0\nignore: {}\npatch: {}\n",
"isPrivate": true,
"licensesPolicy": {
"severities": {},
"orgLicenseRules": {
"AGPL-1.0": {
"licenseType": "AGPL-1.0",
"severity": "high",
"instructions": ""
},
...
"SimPL-2.0": {
"licenseType": "SimPL-2.0",
"severity": "high",
"instructions": ""
}
}
},
"packageManager": "linux",
"ignoreSettings": null,
"docker": {
"baseImageRemediation": {
"code": "SCRATCH_BASE_IMAGE",
"advice": [
{
"message": "Note that we do not currently have vulnerability data for your image.",
"bold": true,
"color": "yellow"
}
]
},
"binariesVulns": {
"issuesData": {},
"affectedPkgs": {}
}
},
"summary": "No known vulnerabilities",
"filesystemPolicy": false,
"uniqueCount": 0,
"projectName": "docker-image|hello-world",
"path": "hello-world"
}
In addition to the --json flag, you can also use the --group-issues flag to display a vulnerability only once in the scan report:
$ docker scan --json --group-issues docker-scan:e2e
{
{
"title": "Improper Check for Dropped Privileges",
...
"packageName": "bash",
"language": "linux",
"packageManager": "debian:10",
"description": "## Overview\nAn issue was discovered in disable_priv_mode in shell.c in GNU Bash through 5.0 patch 11. By default, if Bash is run with its effective UID not equal to its real UID, it will drop privileges by setting its effective UID to its real UID. However, it does so incorrectly. On Linux and other systems that support \"saved UID\" functionality, the saved UID is not dropped. An attacker with command execution in the shell can use \"enable -f\" for runtime loading of a new builtin, which can be a shared object that calls setuid() and therefore regains privileges. However, binaries running with an effective UID of 0 are unaffected.\n\n## References\n- [CONFIRM](https://security.netapp.com/advisory/ntap-20200430-0003/)\n- [Debian Security Tracker](https://security-tracker.debian.org/tracker/CVE-2019-18276)\n- [GitHub Commit](https://github.com/bminor/bash/commit/951bdaad7a18cc0dc1036bba86b18b90874d39ff)\n- [MISC](http://packetstormsecurity.com/files/155498/Bash-5.0-Patch-11-Privilege-Escalation.html)\n- [MISC](https://www.youtube.com/watch?v=-wGtxJ8opa8)\n- [Ubuntu CVE Tracker](http://people.ubuntu.com/~ubuntu-security/cve/CVE-2019-18276)\n",
"identifiers": {
"ALTERNATIVE": [],
"CVE": [
"CVE-2019-18276"
],
"CWE": [
"CWE-273"
]
},
"severity": "low",
"severityWithCritical": "low",
"cvssScore": 7.8,
"CVSSv3": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:F",
...
"from": [
"docker-image|docker-scan@e2e",
"[email protected]"
],
"upgradePath": [],
"isUpgradable": false,
"isPatchable": false,
"name": "bash",
"version": "5.0-4"
},
...
"summary": "880 vulnerable dependency paths",
"filesystemPolicy": false,
"filtered": {
"ignore": [],
"patch": []
},
"uniqueCount": 158,
"projectName": "docker-image|docker-scan",
"platform": "linux/amd64",
"path": "docker-scan:e2e"
}
You can find all the sources of the vulnerability in the from section.
Checking the dependency tree
To view the dependency tree of your image, use the --dependency-tree flag. This displays all the dependencies before the scan result. For example:
$ docker scan --dependency-tree debian:buster
$ docker-image|99138c65ebc7 @ latest
├─ ca-certificates @ 20200601~deb10u1
│ └─ openssl @ 1.1.1d-0+deb10u3
│ └─ openssl/libssl1.1 @ 1.1.1d-0+deb10u3
├─ curl @ 7.64.0-4+deb10u1
│ └─ curl/libcurl4 @ 7.64.0-4+deb10u1
│ ├─ e2fsprogs/libcom-err2 @ 1.44.5-1+deb10u3
│ ├─ krb5/libgssapi-krb5-2 @ 1.17-3
│ │ ├─ e2fsprogs/libcom-err2 @ 1.44.5-1+deb10u3
│ │ ├─ krb5/libk5crypto3 @ 1.17-3
│ │ │ └─ krb5/libkrb5support0 @ 1.17-3
│ │ ├─ krb5/libkrb5-3 @ 1.17-3
│ │ │ ├─ e2fsprogs/libcom-err2 @ 1.44.5-1+deb10u3
│ │ │ ├─ krb5/libk5crypto3 @ 1.17-3
│ │ │ ├─ krb5/libkrb5support0 @ 1.17-3
│ │ │ └─ openssl/libssl1.1 @ 1.1.1d-0+deb10u3
│ │ └─ krb5/libkrb5support0 @ 1.17-3
│ ├─ libidn2/libidn2-0 @ 2.0.5-1+deb10u1
│ │ └─ libunistring/libunistring2 @ 0.9.10-1
│ ├─ krb5/libk5crypto3 @ 1.17-3
│ ├─ krb5/libkrb5-3 @ 1.17-3
│ ├─ openldap/libldap-2.4-2 @ 2.4.47+dfsg-3+deb10u2
│ │ ├─ gnutls28/libgnutls30 @ 3.6.7-4+deb10u4
│ │ │ ├─ nettle/libhogweed4 @ 3.4.1-1
│ │ │ │ └─ nettle/libnettle6 @ 3.4.1-1
│ │ │ ├─ libidn2/libidn2-0 @ 2.0.5-1+deb10u1
│ │ │ ├─ nettle/libnettle6 @ 3.4.1-1
│ │ │ ├─ p11-kit/libp11-kit0 @ 0.23.15-2
│ │ │ │ └─ libffi/libffi6 @ 3.2.1-9
│ │ │ ├─ libtasn1-6 @ 4.13-3
│ │ │ └─ libunistring/libunistring2 @ 0.9.10-1
│ │ ├─ cyrus-sasl2/libsasl2-2 @ 2.1.27+dfsg-1+deb10u1
│ │ │ └─ cyrus-sasl2/libsasl2-modules-db @ 2.1.27+dfsg-1+deb10u1
│ │ │ └─ db5.3/libdb5.3 @ 5.3.28+dfsg1-0.5
│ │ └─ openldap/libldap-common @ 2.4.47+dfsg-3+deb10u2
│ ├─ nghttp2/libnghttp2-14 @ 1.36.0-2+deb10u1
│ ├─ libpsl/libpsl5 @ 0.20.2-2
│ │ ├─ libidn2/libidn2-0 @ 2.0.5-1+deb10u1
│ │ └─ libunistring/libunistring2 @ 0.9.10-1
│ ├─ rtmpdump/librtmp1 @ 2.4+20151223.gitfa8646d.1-2
│ │ ├─ gnutls28/libgnutls30 @ 3.6.7-4+deb10u4
│ │ ├─ nettle/libhogweed4 @ 3.4.1-1
│ │ └─ nettle/libnettle6 @ 3.4.1-1
│ ├─ libssh2/libssh2-1 @ 1.8.0-2.1
│ │ └─ libgcrypt20 @ 1.8.4-5
│ └─ openssl/libssl1.1 @ 1.1.1d-0+deb10u3
├─ gnupg2/dirmngr @ 2.2.12-1+deb10u1
...
Organization: docker-desktop-test
Package manager: deb
Project name: docker-image|99138c65ebc7
Docker image: 99138c65ebc7
Licenses: enabled
Tested 200 dependencies for known issues, found 157 issues.
For more free scans that keep your images secure, sign up to Snyk at https://dockr.ly/3ePqVcp.
For more information about the vulnerability data, see Docker Vulnerability Scanning CLI Cheat Sheet.
Limiting the level of vulnerabilities displayed
Docker scan allows you to choose the level of vulnerabilities displayed in your scan report using the --severity flag. You can set the severity flag to low, medium, orhigh depending on the level of vulnerabilities you’d like to see in your report.
For example, if you set the severity level as medium, the scan report displays all vulnerabilities that are classified as medium and high.
$ docker scan --severity=medium docker-scan:e2e
./bin/docker-scan_darwin_amd64 scan --severity=medium docker-scan:e2e
Testing docker-scan:e2e...
✗ Medium severity vulnerability found in sqlite3/libsqlite3-0
Description: Divide By Zero
Info: https://snyk.io/vuln/SNYK-DEBIAN10-SQLITE3-466337
Introduced through: gnupg2/[email protected]+deb10u1, [email protected]+deb10u1, [email protected]+deb10u1
From: gnupg2/[email protected]+deb10u1 > gnupg2/[email protected]+deb10u1 > sqlite3/[email protected]
From: [email protected]+deb10u1 > subversion/[email protected]+deb10u1 > sqlite3/[email protected]
From: [email protected]+deb10u1 > python-defaults/[email protected] > [email protected]+deb10u1 > python2.7/[email protected]+deb10u1 > sqlite3/[email protected]
✗ Medium severity vulnerability found in sqlite3/libsqlite3-0
Description: Uncontrolled Recursion
...
✗ High severity vulnerability found in binutils/binutils-common
Description: Missing Release of Resource after Effective Lifetime
Info: https://snyk.io/vuln/SNYK-DEBIAN10-BINUTILS-403318
Introduced through: gcc-defaults/g++@4:8.3.0-1
From: gcc-defaults/g++@4:8.3.0-1 > gcc-defaults/gcc@4:8.3.0-1 > [email protected] > [email protected] > binutils/[email protected]
From: gcc-defaults/g++@4:8.3.0-1 > gcc-defaults/gcc@4:8.3.0-1 > [email protected] > [email protected] > binutils/[email protected] > binutils/[email protected]
From: gcc-defaults/g++@4:8.3.0-1 > gcc-defaults/gcc@4:8.3.0-1 > [email protected] > [email protected] > binutils/[email protected] > binutils/[email protected]
and 4 more...
Organization: docker-desktop-test
Package manager: deb
Project name: docker-image|docker-scan
Docker image: docker-scan:e2e
Platform: linux/amd64
Licenses: enabled
Tested 200 dependencies for known issues, found 37 issues.
Provider authentication
If you have an existing Snyk account, you can directly use your Snyk API token:
$ docker scan --login --token SNYK_AUTH_TOKEN
Your account has been authenticated. Snyk is now ready to be used.
If you use the --login flag without any token, you will be redirected to the Snyk website to login.
Prerequisites
To run vulnerability scanning on your Docker images, you must meet the following requirements:
-
Download and install the latest version of Docker Desktop.
-
Sign into Docker Hub.
-
From the Docker Desktop menu, select Sign in/ Create Docker ID. Alternatively, open a terminal and run the command
docker login. -
(Optional) You can create a Snyk account for scans, or use the additional monthly free scans provided by Snyk with your Docker Hub account.
Check your installation by running docker scan --version, it should print the current version of docker scan and the Snyk engine version. For example:
$ docker scan --version
Version: v0.5.0
Git commit: 5a09266
Provider: Snyk (1.432.0)
Note:
Docker Scan uses the Snyk binary installed in your environment by default. If this is not available, it uses the Snyk binary embedded in Docker Desktop. The minimum version required for Snyk is
1.385.0.
Supported options
The high-level docker scan command scans local images using the image name or the image ID. It supports the following options:
| Option | Description |
|---|---|
--accept-license |
Accept the license agreement of the third-party scanning provider |
--dependency-tree |
Display the dependency tree of the image along with scan results |
--exclude-base |
Exclude the base image during scanning. This option requires the --file option to be set |
-f, --file string |
Specify the location of the Dockerfile associated with the image. This option displays a detailed scan result |
--json |
Display the result of the scan in JSON format |
--login |
Log into Snyk using an optional token (using the flag --token), or by using a web-based token |
--reject-license |
Reject the license agreement of the third-party scanning provider |
--severity string |
Only report vulnerabilities of provided level or higher (low, medium, high) |
--token string |
Use the authentication token to log into the third-party scanning provider |
--version |
Display the Docker Scan plugin version |
Known issues
WSL 2
- The Vulnerability scanning feature doesn’t work with Alpine distributions.
- If you are using Debian and OpenSUSE distributions, the login process only works with the
--tokenflag, you won’t be redirected to the Snyk website for authentication.
Feedback
Your feedback is very important to us. Let us know your feedback by creating an issue in the scan-cli-plugin GitHub repository.
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Licensed under the Apache License, Version 2.0.
Docker and the Docker logo are trademarks or registered trademarks of Docker, Inc. in the United States and/or other countries.
Docker, Inc. and other parties may also have trademark rights in other terms used herein.
https://docs.docker.com/engine/scan/
