Security

Prometheus is a sophisticated system with many components and many integrations with other systems. It can be deployed in a variety of trusted and untrusted environments.

This page describes the general security assumptions of Prometheus and the attack vectors that some configurations may enable.

As with any complex system, it is near certain that bugs will be found, some of them security-relevant. If you find a security bug please report it privately to the maintainers listed in the MAINTAINERS of the relevant repository and CC [email protected]. We will fix the issue as soon as possible and coordinate a release date with you. You will be able to choose if you want public acknowledgement of your effort and if you want to be mentioned by name.

Prometheus is maintained by volunteers, not by a company. Therefore, fixing security issues is done on a best-effort basis. We strive to release security fixes within 7 days for: Prometheus, Alertmanager, Node Exporter, Blackbox Exporter, and Pushgateway.

Prometheus

It is presumed that untrusted users have access to the Prometheus HTTP endpoint and logs. They have access to all time series information contained in the database, plus a variety of operational/debugging information.

It is also presumed that only trusted users have the ability to change the command line, configuration file, rule files and other aspects of the runtime environment of Prometheus and other components.

Which targets Prometheus scrapes, how often and with what other settings is determined entirely via the configuration file. The administrator may decide to use information from service discovery systems, which combined with relabelling may grant some of this control to anyone who can modify data in that service discovery system.

Scraped targets may be run by untrusted users. It should not by default be possible for a target to expose data that impersonates a different target. The honor_labels option removes this protection, as can certain relabelling setups.

As of Prometheus 2.0, the --web.enable-admin-api flag controls access to the administrative HTTP API which includes functionality such as deleting time series. This is disabled by default. If enabled, administrative and mutating functionality will be accessible under the /api/*/admin/ paths. The --web.enable-lifecycle flag controls HTTP reloads and shutdowns of Prometheus. This is also disabled by default. If enabled they will be accessible under the /-/reload and /-/quit paths.

In Prometheus 1.x, /-/reload and using DELETE on /api/v1/series are accessible to anyone with access to the HTTP API. The /-/quit endpoint is disabled by default, but can be enabled with the -web.enable-remote-shutdown flag.

The remote read feature allows anyone with HTTP access to send queries to the remote read endpoint. If for example the PromQL queries were ending up directly run against a relational database, then anyone with the ability to send queries to Prometheus (such as via Grafana) can run arbitrary SQL against that database.

Alertmanager

Any user with access to the Alertmanager HTTP endpoint has access to its data. They can create and resolve alerts. They can create, modify and delete silences.

Where notifications are sent to is determined by the configuration file. With certain templating setups it is possible for notifications to end up at an alert-defined destination. For example if notifications use an alert label as the destination email address, anyone who can send alerts to the Alertmanager can send notifications to any email address. If the alert-defined destination is a templatable secret field, anyone with access to either Prometheus or Alertmanager will be able to view the secrets.

Any secret fields which are templatable are intended for routing notifications in the above use case. They are not intended as a way for secrets to be separated out from the configuration files using the template file feature. Any secrets stored in template files could be exfiltrated by anyone able to configure receivers in the Alertmanager configuration file. For example in large setups, each team might have an alertmanager configuration file fragment which they fully control, that are then combined into the full final configuration file.

Pushgateway

Any user with access to the Pushgateway HTTP endpoint can create, modify and delete the metrics contained within. As the Pushgateway is usually scraped with honor_labels enabled, this means anyone with access to the Pushgateway can create any time series in Prometheus.

The --web.enable-admin-api flag controls access to the administrative HTTP API, which includes functionality such as wiping all the existing metric groups. This is disabled by default. If enabled, administrative functionality will be accessible under the /api/*/admin/ paths.

Exporters

Exporters generally only talk to one configured instance with a preset set of commands/requests, which cannot be expanded via their HTTP endpoint.

There are also exporters such as the SNMP and Blackbox exporters that take their targets from URL parameters. Thus anyone with HTTP access to these exporters can make them send requests to arbitrary endpoints. As they also support client-side authentication, this could lead to a leak of secrets such as HTTP Basic Auth passwords or SNMP community strings. Challenge-response authentication mechanisms such as TLS are not affected by this.

Client Libraries

Client libraries are intended to be included in users' applications.

If using a client-library-provided HTTP handler, it should not be possible for malicious requests that reach that handler to cause issues beyond those resulting from additional load and failed scrapes.

Authentication, Authorization, and Encryption

In the future, server-side TLS support will be rolled out to the different Prometheus projects. Those projects include Prometheus, Alertmanager, Pushgateway and the official exporters.

Authentication of clients by TLS client certs will also be supported.

The Go projects will share the same TLS library, which will be based on the Go vanilla crypto/tls library. We default to TLS 1.2 as minimum version. Our policy regarding this is based on Qualys SSL Labs recommendations, where we strive to achieve a grade 'A' with a default configuration and correctly provided certificates, while sticking as closely as possible to the upstream Go defaults. Achieving that grade provides a balance between perfect security and usability.

TLS will be added to Java exporters in the future.

If you have special TLS needs, like a different cipher suite or older TLS version, you can tune the minimum TLS version and the ciphers, as long as the cipher is not marked as insecure in the crypto/tls library. If that still does not suit you, the current TLS settings enable you to build a secure tunnel between the servers and reverse proxies with more special requirements.

HTTP Basic Authentication will also be supported. Basic Authentication can be used without TLS, but it will then expose usernames and passwords in cleartext over the network.

On the server side, basic authentication passwords are stored as hashes with the bcrypt algorithm. It is your responsibility to pick the number of rounds that matches your security standards. More rounds make brute-force more complicated at the cost of more CPU power and more time to authenticate the requests.

Various Prometheus components support client-side authentication and encryption. If TLS client support is offered, there is often also an option called insecure_skip_verify which skips SSL verification.

API Security

As administrative and mutating endpoints are intended to be accessed via simple tools such as cURL, there is no built in CSRF protection as that would break such use cases. Accordingly when using a reverse proxy, you may wish to block such paths to prevent CSRF.

For non-mutating endpoints, you may wish to set CORS headers such as Access-Control-Allow-Origin in your reverse proxy to prevent XSS.

If you are composing PromQL queries that include input from untrusted users (e.g. URL parameters to console templates, or something you built yourself) who are not meant to be able to run arbitrary PromQL queries make sure any untrusted input is appropriately escaped to prevent injection attacks. For example up{job="<user_input>"} would become up{job=""} or some_metric{zzz=""} if the <user_input> was "} or some_metric{zzz=".

For those using Grafana note that dashboard permissions are not data source permissions, so do not limit a user's ability to run arbitrary queries in proxy mode.

Secrets

Non-secret information or fields may be available via the HTTP API and/or logs.

In Prometheus, metadata retrieved from service discovery is not considered secret. Throughout the Prometheus system, metrics are not considered secret.

Fields containing secrets in configuration files (marked explicitly as such in the documentation) will not be exposed in logs or via the HTTP API. Secrets should not be placed in other configuration fields, as it is common for components to expose their configuration over their HTTP endpoint. It is the responsibility of the user to protect files on disk from unwanted reads and writes.

Secrets from other sources used by dependencies (e.g. the AWS_SECRET_KEY environment variable as used by EC2 service discovery) may end up exposed due to code outside of our control or due to functionality that happens to expose wherever it is stored.

Denial of Service

There are some mitigations in place for excess load or expensive queries. However, if too many or too expensive queries/metrics are provided components will fall over. It is more likely that a component will be accidentally taken out by a trusted user than by malicious action.

It is the responsibility of the user to ensure they provide components with sufficient resources including CPU, RAM, disk space, IOPS, file descriptors, and bandwidth.

It is recommended to monitor all components for failure, and to have them automatically restart on failure.

Libraries

This document considers vanilla binaries built from the stock source code. Information presented here does not apply if you modify Prometheus source code, or use Prometheus internals (beyond the official client library APIs) in your own code.

Build Process

The build pipeline for Prometheus runs on third-party providers to which many members of the Prometheus development team and the staff of those providers have access. If you are concerned about the exact provenance of your binaries, it is recommended to build them yourself rather than relying on the pre-built binaries provided by the project.

Prometheus-Community

The repositories under the Prometheus-Community organization are supported by third-party maintainers.

If you find a security bug in the Prometheus-Community organization, please report it privately to the maintainers listed in the MAINTAINERS of the relevant repository and CC [email protected].

Some repositories under that organization might have a different security model than the ones presented in this document. In such a case, please refer to the documentation of those repositories.

External audits

CNCF sponsored an external security audit by cure53 which ran from April 2018 to June 2018.

For more details, please read the final report of the audit.

In 2020, there was a second audit by cure53 of Node Exporter.

This documentation is open-source. Please help improve it by filing issues or pull requests.