Malware Scanning

Overview

Anchore Enterprise now supports the use of the open-source ClamAV malware scanner to detect malicious code embedded in container images. This scan occurs only at analysis time when the image content itself is available, and the scan results are available via the Engine API as well as for consumption in new policy gates to allow gating of image with malware findings.

Signature DB Updates

Each analyzer service will run a malware signature update before analyzing each image. This does add some latency to the overall analysis time but ensures the signatures are as up-to-date as possible for each image analyzed. The update behavior can be disabled if you prefer to manage the freshness of the db via another route, such as a shared filesystem mounted to all analyzer nodes that is updated on a schedule. See the configuration section for details on disabling the db update.

The status of the db update is present in each scan output for each image.

Scan Results

The malware content type is a list of scan results. Each result is the run of a malware scanner, by default clamav.

The list of files found to contain malware signature matches is in the findings property of each scan result. An empty array value indicates no matches found.

The metadata property provides generic metadata specific to the scanner. For the ClamAV implementation, this includes the version data about the signature db used and if the db update was enabled during the scan. If the db update is disabled, then the db_version property of the metadata will not have values since the only way to get the version metadata is during a db update.

{
    "content": [
        {
            "findings": [
                {
                    "path": "/somebadfile",
                    "signature": "Unix.Trojan.MSShellcode-40"
                },
                {
                    "path": "/somedir/somepath/otherbadfile",
                    "signature": "Unix.Trojan.MSShellcode-40"
                }
            ],
            "metadata": {
                "db_update_enabled": true,
                "db_version": {
                    "bytecode": "331",
                    "daily": "25890",
                    "main": "59"
                }
            },
            "scanner": "clamav"
        }
    ],
    "content_type": "malware",
    "imageDigest": "sha256:0eb874fcad5414762a2ca5b2496db5291aad7d3b737700d05e45af43bad3ce4d"
}

Policy Rules

A policy gate called malware is available with two new triggers:

  • scans trigger will fire for each file and signature combination found in the image so that you can fail an evaluation of an image if malware was detected during the analysis scans
  • scan_not_run trigger will fire if there are no malware scans (even empty) available for the image

See policy checks for more details