Cosign Vulnerability Attestation

Generate Cosign Vulnerability Scan Record

Trivy generates reports in the Cosign vulnerability scan record format.

You can use the regular subcommands (like image, fs and rootfs) and specify cosign-vuln with the --format option.

$ trivy image --format cosign-vuln --output vuln.json alpine:3.10

<details> <summary>Result</summary>

json

{
  "invocation": {
    "parameters": null,
    "uri": "",
    "event_id": "",
    "builder.id": ""
  },
  "scanner": {
    "uri": "pkg:github/aquasecurity/[email protected]",
    "version": "v0.30.1-8-gf9cb8a28",
    "db": {
      "uri": "",
      "version": ""
    },
    "result": {
      "SchemaVersion": 2,
      "CreatedAt": 1629894030,
      "ArtifactName": "alpine:3.10",
      "ArtifactType": "container_image",
      "Metadata": {
        "OS": {
          "Family": "alpine",
          "Name": "3.10.9",
          "EOSL": true
        },
        "ImageID": "sha256:e7b300aee9f9bf3433d32bc9305bfdd22183beb59d933b48d77ab56ba53a197a",
        "DiffIDs": [
          "sha256:9fb3aa2f8b8023a4bebbf92aa567caf88e38e969ada9f0ac12643b2847391635"
        ],
        "RepoTags": [
          "alpine:3.10"
        ],
        "RepoDigests": [
          "alpine@sha256:451eee8bedcb2f029756dc3e9d73bab0e7943c1ac55cff3a4861c52a0fdd3e98"
        ],
        "ImageConfig": {
          "architecture": "amd64",
          "container": "fdb7e80e3339e8d0599282e606c907aa5881ee4c668a68136119e6dfac6ce3a4",
          "created": "2021-04-14T19:20:05.338397761Z",
          "docker_version": "19.03.12",
          "history": [
            {
              "created": "2021-04-14T19:20:04.987219124Z",
              "created_by": "/bin/sh -c #(nop) ADD file:c5377eaa926bf412dd8d4a08b0a1f2399cfd708743533b0aa03b53d14cb4bb4e in / "
            },
            {
              "created": "2021-04-14T19:20:05.338397761Z",
              "created_by": "/bin/sh -c #(nop)  CMD [\"/bin/sh\"]",
              "empty_layer": true
            }
          ],
          "os": "linux",
          "rootfs": {
            "type": "layers",
            "diff_ids": [
              "sha256:9fb3aa2f8b8023a4bebbf92aa567caf88e38e969ada9f0ac12643b2847391635"
            ]
          },
          "config": {
            "Cmd": [
              "/bin/sh"
            ],
            "Env": [
              "PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin"
            ],
            "Image": "sha256:eb2080c455e94c22ae35b3aef9e078c492a00795412e026e4d6b41ef64bc7dd8"
          }
        }
      },
      "Results": [
        {
          "Target": "alpine:3.10 (alpine 3.10.9)",
          "Class": "os-pkgs",
          "Type": "alpine",
          "Vulnerabilities": [
            {
              "VulnerabilityID": "CVE-2021-36159",
              "PkgName": "apk-tools",
              "InstalledVersion": "2.10.6-r0",
              "FixedVersion": "2.10.7-r0",
              "Layer": {
                "Digest": "sha256:396c31837116ac290458afcb928f68b6cc1c7bdd6963fc72f52f365a2a89c1b5",
                "DiffID": "sha256:9fb3aa2f8b8023a4bebbf92aa567caf88e38e969ada9f0ac12643b2847391635"
              },
              "SeveritySource": "nvd",
              "PrimaryURL": "https://avd.aquasec.com/nvd/cve-2021-36159",
              "DataSource": {
                "ID": "alpine",
                "Name": "Alpine Secdb",
                "URL": "https://secdb.alpinelinux.org/"
              },
              "Description": "libfetch before 2021-07-26, as used in apk-tools, xbps, and other products, mishandles numeric strings for the FTP and HTTP protocols. The FTP passive mode implementation allows an out-of-bounds read because strtol is used to parse the relevant numbers into address bytes. It does not check if the line ends prematurely. If it does, the for-loop condition checks for the '\\0' terminator one byte too late.",
              "Severity": "CRITICAL",
              "CweIDs": [
                "CWE-125"
              ],
              "CVSS": {
                "nvd": {
                  "V2Vector": "AV:N/AC:L/Au:N/C:P/I:N/A:P",
                  "V3Vector": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H",
                  "V2Score": 6.4,
                  "V3Score": 9.1
                }
              },
              "References": [
                "https://github.com/freebsd/freebsd-src/commits/main/lib/libfetch",
                "https://gitlab.alpinelinux.org/alpine/apk-tools/-/issues/10749",
                "https://lists.apache.org/thread.html/r61db8e7dcb56dc000a5387a88f7a473bacec5ee01b9ff3f55308aacc@%3Cdev.kafka.apache.org%3E",
                "https://lists.apache.org/thread.html/r61db8e7dcb56dc000a5387a88f7a473bacec5ee01b9ff3f55308aacc@%3Cusers.kafka.apache.org%3E",
                "https://lists.apache.org/thread.html/rbf4ce74b0d1fa9810dec50ba3ace0caeea677af7c27a97111c06ccb7@%3Cdev.kafka.apache.org%3E",
                "https://lists.apache.org/thread.html/rbf4ce74b0d1fa9810dec50ba3ace0caeea677af7c27a97111c06ccb7@%3Cusers.kafka.apache.org%3E"
              ],
              "PublishedDate": "2021-08-03T14:15:00Z",
              "LastModifiedDate": "2021-10-18T12:19:00Z"
            }
          ]
        }
      ]
    }
  },
  "metadata": {
    "scanStartedOn": "2022-07-24T17:14:04.864682+09:00",
    "scanFinishedOn": "2022-07-24T17:14:04.864682+09:00"
  }
}

</details>

Create Cosign Vulnerability Attestation

Cosign supports generating and verifying in-toto attestations. This tool enables you to sign and verify Cosign vulnerability attestation.

!!! note In the following examples, the cosign command will write an attestation to a target OCI registry, so you must have permission to write. If you want to avoid writing an OCI registry and only want to see an attestation, add the --no-upload option to the cosign command.

Sign with a local key pair

Cosign can generate key pairs and use them for signing and verification. After you run the following command, you will get a public and private key pair. Read more about how to generate key pairs.

bash

$ cosign generate-key-pair

In the following example, Trivy generates a cosign vulnerability scan record, and then Cosign attaches an attestation of it to a container image with a local key pair.

$ trivy image --format cosign-vuln --output vuln.json <IMAGE>
$ cosign attest --key /path/to/cosign.key --type vuln --predicate vuln.json <IMAGE>

Then, you can verify attestations on the image.

$ cosign verify-attestation --key /path/to/cosign.pub --type vuln <IMAGE>

Keyless signing

You can use Cosign to sign without keys by authenticating with an OpenID Connect protocol supported by sigstore (Google, GitHub, or Microsoft).

$ trivy image --format cosign-vuln -o vuln.json <IMAGE>
$ cosign attest --type vuln --predicate vuln.json <IMAGE>

This will provide a certificate in the output section.

You can verify attestations:

$ cosign verify-attestation --certificate=path-to-the-certificate --type vuln --certificate-identity Email-used-to-sign  --certificate-oidc-issuer='the-issuer-used' <IMAGE>