Document the security tools maintenance and vulnerabilities DB update

Addresses the following questions:

- How often do we update the vulnerability DB or analyzers?
- Do we have to update GitLab to benefit from latest vulnerabilities
  definitions?

doc/user/application_security/container_scanning/index.md

@@ -206,6 +206,11 @@ vulnerabilities in your groups and projects. Read more about the
 Once a vulnerability is found, you can interact with it. Read more on how to
 [interact with the vulnerabilities](../index.md#interacting-with-the-vulnerabilities).
 
+## Vulnerabilities database update
+
+For more information about the vulnerabilities database update, check the
+[maintenance table](../index.md#maintenance-and-update-of-the-vulnerabilities-database).
+
 ## Troubleshooting
 
 ### docker: Error response from daemon: failed to copy xattrs

doc/user/application_security/dast/index.md

@@ -259,3 +259,8 @@ vulnerabilities in your groups and projects. Read more about the
 
 Once a vulnerability is found, you can interact with it. Read more on how to
 [interact with the vulnerabilities](../index.md#interacting-with-the-vulnerabilities).
+
+## Vulnerabilities database update
+
+For more information about the vulnerabilities database update, check the
+[maintenance table](../index.md#maintenance-and-update-of-the-vulnerabilities-database).

doc/user/application_security/dependency_scanning/index.md

@@ -404,6 +404,11 @@ vulnerabilities in your groups and projects. Read more about the
 Once a vulnerability is found, you can interact with it. Read more on how to
 [interact with the vulnerabilities](../index.md#interacting-with-the-vulnerabilities).
 
+## Vulnerabilities database update
+
+For more information about the vulnerabilities database update, check the
+[maintenance table](../index.md#maintenance-and-update-of-the-vulnerabilities-database).
+
 ## Dependency List
 
 > [Introduced](https://gitlab.com/gitlab-org/gitlab-ee/issues/10075) in [GitLab Ultimate](https://about.gitlab.com/pricing/) 12.0.

doc/user/application_security/index.md

@@ -10,7 +10,7 @@ high-level view on projects and groups, and start remediation processes when nee
 
 GitLab can scan and report any vulnerabilities found in your project.
 
-| Secure scanning tools                                                        | Description                                                            |
+| Secure scanning tool                                                         | Description                                                            |
 |:-----------------------------------------------------------------------------|:-----------------------------------------------------------------------|
 | [Container Scanning](container_scanning/index.md) **[ULTIMATE]**             | Scan Docker containers for known vulnerabilities.                      |
 | [Dependency Scanning](dependency_scanning/index.md) **[ULTIMATE]**           | Analyze your dependencies for known vulnerabilities.                   |
@@ -19,6 +19,29 @@ GitLab can scan and report any vulnerabilities found in your project.
 | [Security Dashboard](security_dashboard/index.md) **[ULTIMATE]**             | View vulnerabilities in all your projects and groups.                  |
 | [Static Application Security Testing (SAST)](sast/index.md) **[ULTIMATE]**   | Analyze source code for known vulnerabilities.                         |
 
+## Maintenance and update of the vulnerabilities database
+
+The various scanning tools and the vulnerabilities database are updated regularly.
+
+| Secure scanning tool                                         | Vulnerabilities database updates          |
+|:-------------------------------------------------------------|-------------------------------------------|
+| [Container Scanning](container_scanning/index.md)            | Uses `clair` underneath and the latest `clair-db` version is used for each job run by running the [`latest` docker image tag](https://gitlab.com/gitlab-org/gitlab-ee/blob/438a0a56dc0882f22bdd82e700554525f552d91b/lib/gitlab/ci/templates/Security/Container-Scanning.gitlab-ci.yml#L37). The `clair-db` database [is updated daily according to the author](https://github.com/arminc/clair-local-scan#clair-server-or-local). |
+| [Dependency Scanning](dependency_scanning/index.md)          | Relies on `bundler-audit` (for Rubygems), `retire.js` (for NPM packages) and `gemnasium` (GitLab's own tool for all libraries). `bundler-audit` and `retire.js` both fetch their vulnerabilities data from GitHub repositories, so vulnerabilities added to `ruby-advisory-db` and `retire.js` are immediately available. The tools themselves are updated once per month if there's a new version. The [Gemnasium DB](https://gitlab.com/gitlab-org/security-products/gemnasium-db) is updated at least once a week. |
+| [Dynamic Application Security Testing (DAST)](dast/index.md) | Updated weekly on Sundays. The underlying tool, `zaproxy`, downloads fresh rules at startup. |
+| [Static Application Security Testing (SAST)](sast/index.md)  | Relies exclusively on [the tools GitLab is wrapping](sast/index.md#supported-languages-and-frameworks). The underlying analyzers are updated at least once per month if a relevant update is available. The vulnerabilities database is updated by the upstream tools. |
+
+You don't have to update GitLab to benefit from the latest vulnerabilities definitions,
+but you may have to in the future.
+
+The security tools are released as Docker images, and the vendored job definitions
+to enable them are using the `x-y-stable` image tags that get overridden each time a new
+release of the tools is pushed. The Docker images are updated to match the
+previous GitLab releases, so they automatically get the latest versions of the
+scanning tools without the user having to do anything.
+
+This workflow comes with some drawbacks and there's a
+[plan to change this](https://gitlab.com/gitlab-org/gitlab-ee/issues/9725).
+
 ## Interacting with the vulnerabilities
 
 > Introduced in [GitLab Ultimate](https://about.gitlab.com/pricing) 10.8.

doc/user/application_security/sast/index.md

@@ -269,7 +269,7 @@ it highlighted:
           "url": "https://cwe.mitre.org/data/definitions/330.html"
         }
       ]
-    },   
+    },
     {
       "category": "sast",
       "message": "Probable insecure usage of temp file/directory.",
@@ -296,7 +296,7 @@ it highlighted:
           "url": "https://docs.openstack.org/bandit/latest/plugins/b108_hardcoded_tmp_directory.html"
         }
       ]
-    },    
+    },
   ],
   "remediations": []
 }
@@ -320,7 +320,7 @@ the report JSON unless stated otherwise. Presence of optional fields depends on
 | `vulnerabilities[].scanner`             | A node that describes the analyzer used to find this vulnerability. |
 | `vulnerabilities[].scanner.id`          | Id of the scanner as a snake_case string. |
 | `vulnerabilities[].scanner.name`        | Name of the scanner, for display purposes. |
-| `vulnerabilities[].location`            | A node that tells where the vulnerability is located. | 
+| `vulnerabilities[].location`            | A node that tells where the vulnerability is located. |
 | `vulnerabilities[].location.file`       | Path to the file where the vulnerability is located. Optional. |
 | `vulnerabilities[].location.start_line` | The first line of the code affected by the vulnerability. Optional. |
 | `vulnerabilities[].location.end_line`   | The last line of the code affected by the vulnerability. Optional. |
@@ -330,7 +330,7 @@ the report JSON unless stated otherwise. Presence of optional fields depends on
 | `vulnerabilities[].identifiers[].type`  | Type of the identifier. Possible values: common identifier types (among `cve`, `cwe`, `osvdb`, and `usn`) or analyzer-dependent ones (e.g., `bandit_test_id` for [Bandit analyzer](https://wiki.openstack.org/wiki/Security/Projects/Bandit)). |
 | `vulnerabilities[].identifiers[].name`  | Name of the identifier for display purposes. |
 | `vulnerabilities[].identifiers[].value` | Value of the identifier for matching purposes. |
-| `vulnerabilities[].identifiers[].url`   | URL to identifier's documentation. Optional. | 
+| `vulnerabilities[].identifiers[].url`   | URL to identifier's documentation. Optional. |
 
 ## Secret detection
 
@@ -363,3 +363,8 @@ vulnerabilities in your groups and projects. Read more about the
 
 Once a vulnerability is found, you can interact with it. Read more on how to
 [interact with the vulnerabilities](../index.md#interacting-with-the-vulnerabilities).
+
+## Vulnerabilities database update
+
+For more information about the vulnerabilities database update, check the
+[maintenance table](../index.md#maintenance-and-update-of-the-vulnerabilities-database).