82 lines
3.2 KiB
Markdown
82 lines
3.2 KiB
Markdown
---
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layout: "docs"
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page_title: "Audit Devices"
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sidebar_current: "docs-audit"
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description: |-
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Audit devices are mountable devices that log requests and responses in Vault.
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---
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# Audit Devices
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Audit devices are the components in Vault that keep a detailed log of all
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requests and response to Vault. Because every operation with Vault is an API
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request/response, the audit log contains _every authenticated_ interaction with
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Vault, including errors.
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Multiple audit devices can be enabled and Vault will send the audit logs to
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both. This allows you to not only have a redundant copy, but also a second copy
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in case the first is tampered with.
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## Format
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Each line in the audit log is a JSON object. The `type` field specifies what
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type of object it is. Currently, only two types exist: `request` and `response`.
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The line contains all of the information for any given request and response. By
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default, all the sensitive information is first hashed before logging in the
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audit logs.
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## Sensitive Information
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The audit logs contain the full request and response objects for every
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interaction with Vault. The request and response can be matched utilizing a
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unique identifier assigned to each request. The data in the request and the
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data in the response (including secrets and authentication tokens) will be
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hashed with a salt using HMAC-SHA256.
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The purpose of the hash is so that secrets aren't in plaintext within your
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audit logs. However, you're still able to check the value of secrets by
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generating HMACs yourself; this can be done with the audit device's hash
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function and salt by using the `/sys/audit-hash` API endpoint (see the
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documentation for more details).
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## Enabling/Disabling Audit Devices
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When a Vault server is first initialized, no auditing is enabled. Audit
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devices must be enabled by a root user using `vault audit enable`.
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When enabling an audit device, options can be passed to it to configure it.
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For example, the command below enables the file audit device:
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```text
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$ vault audit enable file file_path=/var/log/vault_audit.log
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```
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In the command above, we passed the "file_path" parameter to specify the path
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where the audit log will be written to. Each audit device has its own
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set of parameters. See the documentation to the left for more details.
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When an audit device is disabled, it will stop receiving logs immediately.
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The existing logs that it did store are untouched.
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## Blocked Audit Devices
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If there are any audit devices enabled, Vault requires that at least
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one be able to persist the log before completing a Vault request.
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!> If you have only one audit device enabled, and it is blocking (network
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block, etc.), then Vault will be _unresponsive_. Vault **will not** complete
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any requests until the audit device can write.
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If you have more than one audit device, then Vault will complete the request
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as long as one audit device persists the log.
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Vault will not respond to requests if audit devices are blocked because
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audit logs are critically important and ignoring blocked requests opens
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an avenue for attack. Be absolutely certain that your audit devices cannot
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block.
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## API
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Audit devices also have a full HTTP API. Please see the [Audit device API
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docs](/api/system/audit.html) for more details.
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