> ## Documentation Index
> Fetch the complete documentation index at: https://docs.snapsec.co/llms.txt
> Use this file to discover all available pages before exploring further.

# CRT

> Fetch subdomains from certificate transparency logs through crt.sh into Snapsec ASM.

## CRT Integration with Snapsec ASM

The **CRT adapter** enables Snapsec ASM to discover subdomains by querying public certificate transparency logs from **crt**.

This provides fast and reliable external asset discovery for any domain with issued TLS certificates.

***

## 1. What CRT Integration Does

ASM uses CRT to automatically:

* Discover newly issued subdomains
* Identify wildcard certificate expansions
* Track certificate-based exposure
* Reveal forgotten or legacy domains
* Add all discovered assets into the ASM inventory

This is one of the primary sources of external surface expansion detection.

***

## 2. Prerequisites

No API key is required.

CRT integration works using public CT log queries.

***

## 3. How to Install

1. Go to **ASM → Integrations**
2. Select **CRT**
3. Click **Install**

ASM immediately begins querying certificate transparency logs.

***

## 4. What Data Gets Imported

* Subdomains
* Certificate CN / SAN entries
* Certificate issuance metadata
* Historical and newly issued CT records

Assets are automatically enriched and added to the ASM **Asset Catalog**.

***

## 5. Sync Behavior

* **Frequent automatic refreshes** pull new CT log entries
* Each newly discovered certificate results in new asset detection
* You may run **Manual Refresh** anytime

***

## Next Steps

<Card title="View Discovered Subdomains" icon="arrow-right" href="/products/asm/asset-catalog">
  Explore subdomains discovered via CRT and other ASM adapters.
</Card>