---
description: You can now use a predefined DLP profile to detect, block, or redirect unsanitized HAR files in HTTP traffic, preventing sensitive data like session cookies and authentication tokens from being exfiltrated.
title: Detect and sanitize HAR files
image: https://developers.cloudflare.com/changelog/post/2026-03-25-har-file-detection-and-sanitization/og.png?v=0cfcc25874ee42b2
---

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March 25, 2026

## Detect and sanitize HAR files

[Data Loss Prevention](https://developers.cloudflare.com/cloudflare-one/data-loss-prevention/)

Copy as Markdown| [View as Markdown](https://developers.cloudflare.com/changelog/post/2026-03-25-har-file-detection-and-sanitization/index.md)| [Agent setup](https://developers.cloudflare.com/agent-setup/)

HTTP Archive (HAR) files are used by engineering and support teams to capture and share web traffic logs for troubleshooting. However, these files routinely contain highly sensitive data — including session cookies, authorization headers, and other credentials — that can pose a significant risk if uploaded to third-party services without being reviewed or cleaned first.

Gateway now includes a predefined DLP profile called **Unsanitized HAR** that detects HAR files in HTTP traffic. You can use this profile in a Gateway HTTP policy to either block HAR file uploads entirely or redirect users to a sanitization tool before allowing the upload to proceed.

#### How to configure a HAR file policy

In the [Cloudflare dashboard ↗︎](https://dash.cloudflare.com/), go to **Zero Trust** > **Traffic policies** > **Firewall Policies** > **HTTP** and create a new HTTP policy using the **DLP Profile** selector:

| Selector | Operator | Value | Action |
| --- | --- | --- | --- |
| DLP Profile | in | *Unsanitized HAR* | |

Then choose one of the following actions:

- **Block**: Prevents the upload of any HAR file that has not been sanitized by Cloudflare's sanitizer. Use this for strict environments where HAR file sharing must be disallowed entirely.
- **Block** with **Gateway Redirect**: Intercepts the upload and redirects the user to `https://har-sanitizer.pages.dev/`, where they can sanitize the file. Once sanitized, the user can re-upload the clean file and proceed with their workflow.

#### Sanitized HAR recognition

HAR files processed by the Cloudflare HAR sanitizer receive a tamper-evident sanitized marker. DLP recognizes this marker and will not re-trigger the policy on a file that has already been sanitized and has not been modified since. If a previously sanitized file is edited, it will be treated as unsanitized and flagged again.

#### Visibility in Gateway logs

Gateway logs will reflect whether a detected HAR file was classified as **Unsanitized** or **Sanitized**, giving your security team full visibility into HAR file activity across your organization.

For more information, refer to [predefined DLP profiles](https://developers.cloudflare.com/cloudflare-one/data-loss-prevention/dlp-profiles/predefined-profiles/).

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