﻿---
title: Scripting and security in Painless
description: As part of its core design, Painless provides secure scripting capabilities across Elasticsearch. Introduced in Elasticsearch 5.0 as a replacement for...
url: https://docs-v3-preview.elastic.dev/elastic/docs-content/pull/4326/explore-analyze/scripting/modules-scripting-security
products:
  - Elasticsearch
---

# Scripting and security in Painless
As part of its core design, Painless provides secure scripting capabilities across Elasticsearch.
Introduced in [Elasticsearch 5.0](https://www.elastic.co/blog/painless-a-new-scripting-language) as a replacement for Groovy, Painless is purpose-built for Elasticsearch, enabling native performance while preventing unauthorized access to system resources.
By operating in a controlled sandbox environment, Painless ensures that you won’t get compromised when using it. Painless only allows pre-approved operations through fine-grained allowlists. Scripts cannot access file systems, networks, or other system resources that could compromise your cluster while still providing the flexibility you need for search scoring, data processing, and operational automation.

## Security Architecture Overview

The fine-grained allowlist operates as the first security layer. Anything that is not part of the allowlist will result in an error.
As another layer of security, Elasticsearch uses [Seccomp](https://en.wikipedia.org/wiki/Seccomp) in Linux, [Seatbelt](https://www.chromium.org/developers/design-documents/sandbox/osx-sandboxing-design) in macOS, and [ActiveProcessLimit](https://msdn.microsoft.com/en-us/library/windows/desktop/ms684147) on Windows to prevent Elasticsearch from forking or running other processes.
Finally, scripts used in [scripted metrics aggregations](https://docs-v3-preview.elastic.dev/elastic/elasticsearch/tree/main/reference/aggregations/search-aggregations-metrics-scripted-metric-aggregation) can be restricted to a defined list of scripts or forbidden altogether. This can prevent users from running particularly slow or resource-intensive aggregation queries.
You can modify the allowed script types setting to restrict the type of scripts that are allowed to run and control the available [contexts](https://docs-v3-preview.elastic.dev/elastic/elasticsearch/tree/main/reference/scripting-languages/painless/painless-contexts) that scripts can run in. As well, you can use the Elasticsearch [security features](https://docs-v3-preview.elastic.dev/elastic/docs-content/pull/4326/deploy-manage/security) to enhance your defence strategy.

## Allowed script types setting

Elasticsearch supports two script types: `inline` and `stored`. By default, Elasticsearch is configured to run both types of scripts. To limit what type of scripts are run, set `script.allowed_types` to `inline` or `stored`. To prevent any scripts from running, set `script.allowed_types` to `none`. If you use Kibana, set `script.allowed_types` to both or just `inline`. Some Kibana features rely on inline scripts and do not function as expected if Elasticsearch does not allow inline scripts.
For example, to run `inline` scripts but not `stored` scripts:
```
script.allowed_types: inline
```


## Allowed script contexts setting

By default, all script contexts are permitted. Use the `script.allowed_contexts` setting to specify the contexts that are allowed. To specify that no contexts are allowed, set `script.allowed_contexts` to `none`. For example, to allow scripts to run only in `scoring` and `update` contexts:
```
script.allowed_contexts: score, update
```


## Allowed scripts in scripted metrics aggregations

By default, all scripts are permitted in [scripted metrics aggregations](https://docs-v3-preview.elastic.dev/elastic/elasticsearch/tree/main/reference/aggregations/search-aggregations-metrics-scripted-metric-aggregation). To restrict the set of allowed scripts, set [`search.aggs.only_allowed_metric_scripts`](https://docs-v3-preview.elastic.dev/elastic/elasticsearch/tree/main/reference/elasticsearch/configuration-reference/search-settings#search-settings-only-allowed-scripts) to `true` and provide the allowed scripts using [`search.aggs.allowed_inline_metric_scripts`](https://docs-v3-preview.elastic.dev/elastic/elasticsearch/tree/main/reference/elasticsearch/configuration-reference/search-settings#search-settings-allowed-inline-scripts) and/or [`search.aggs.allowed_stored_metric_scripts`](https://docs-v3-preview.elastic.dev/elastic/elasticsearch/tree/main/reference/elasticsearch/configuration-reference/search-settings#search-settings-allowed-stored-scripts).
To disallow certain script types, omit the corresponding script list (`search.aggs.allowed_inline_metric_scripts` or `search.aggs.allowed_stored_metric_scripts`) or set it to an empty array. When both script lists are not empty, the given stored scripts and the given inline scripts will be allowed.
```yaml
search.aggs.only_allowed_metric_scripts: true
search.aggs.allowed_inline_metric_scripts: []
search.aggs.allowed_stored_metric_scripts:
   - script_id_1
   - script_id_2
   - script_id_3
   - script_id_4
```

Conversely, the next example allows specific inline scripts but no stored scripts:
```yaml
search.aggs.only_allowed_metric_scripts: true
search.aggs.allowed_inline_metric_scripts:
   - 'state.transactions = []'
   - 'state.transactions.add(doc.some_field.value)'
   - 'long sum = 0; for (t in state.transactions) { sum += t } return sum'
   - 'long sum = 0; for (a in states) { sum += a } return sum'
search.aggs.allowed_stored_metric_scripts: []
```