Skip to main content

YaraHunter

Deepfence YaraHunter scans container images, running Docker containers, and filesystems to find indicators of malware. It uses a YARA ruleset to identify resources that match known malware signatures, and may indicate that the container or filesystem has been compromised.

Key capabilities:

  • Scan running and at-rest containers; scan filesystems; scan during CI/CD build operations
  • Run anywhere: highly-portable, docker container form factor
  • Designed for automation: easy-to-deploy, easy-to-parse JSON output

YaraHunter in Action

Yadare in Action

Example: Finding Indicators of Compromise in a Container Image

Images may be compromised with the installation of a cryptominer such as XMRig. In the following example, we'll scan a legitimiate cryptominer image that contains the same xmrig software that is often installed through an exploit:

docker pull metal3d/xmrig

docker run -i --rm --name=deepfence-yarahunter \
-v /var/run/docker.sock:/var/run/docker.sock \
-v /tmp:/home/deepfence/output \
deepfenceio/deepfence_malware_scanner_ce:2.0.0 \
--image-name metal3d/xmrig:latest \
--output=json > xmrig-scan.json

This returns, among other things, clear indication of the presence of XMRig. Note that we store the output (/tmp/xmrig-scan.json) for quick and easy manipulation:

# Extract the IOC array values.  From these, extract the values of the 'Matched Rule Name' key
cat /tmp/xmrig-scan.json | jq '.IOC[] | ."Matched Rule Name"'

This returns a list of the IOCs identified in the container we scanned.

When to use YaraHunter

YaraHunter can be used in the following ways:

  • At build-and-test: scan build artifacts in the CI/CD pipeline, reporting on possible indicators of malware
  • At rest: scan local container images, for example, before they are deployed, to verify they do not contain malware
  • At runtime: scan running docker containers, for example, if you observe unusual network traffic or CPU activity
  • Against filesystems: at any time, YaraHunter can scan a local filesystems for indicators of compromise