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<!-- Licensed under AGPL-3.0 — see LICENSE file for details. -->
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---
name: implementing-cross-origin-isolation
description: >-
  Implement Cross-Origin Isolation using COOP and COEP headers to enable SharedArrayBuffer, high-resolution timers, and protection against Spectre-class side-channel attacks.
domain: cybersecurity
subdomain: browser-security
tags:
  - cross-origin-isolation
  - coop
  - coep
  - spectre
version: "1.0"
author: defconxt
license: AGPL-3.0
metadata:
  mitre-attack: ["T1189"]
  frameworks: ["OWASP", "W3C"]
  tools: ["curl", "securityheaders", "devtools"]
---

# Implementing Cross Origin Isolation

## Overview

Implement Cross-Origin Isolation using COOP and COEP headers to enable SharedArrayBuffer, high-resolution timers, and protection against Spectre-class side-channel attacks.

## Prerequisites

| Tool / Requirement | Details |
|---|---|
| `curl` | Security tooling |
| `securityheaders` | Security tooling |
| `devtools` | Security tooling |
| Web server configuration access, understanding of COOP/COEP requirements | Environment requirement |

## Quick Reference

```bash
# Quick start commands
node scripts/agent.js --help
curl -sI https://target.com | grep -iE 'cross-origin-(opener|embedder)-policy'
```

## Workflow

### Step 1: Check Isolation Status

```bash
curl -sI https://target.com | grep -iE 'cross-origin-(opener|embedder)-policy'
```

### Step 2: Generate COOP/COEP Config

```bash
node scripts/agent.js generate --url https://target.com --strict
```

### Step 3: Deploy Headers

```bash
node scripts/agent.js deploy --url https://target.com --config isolation.json
```

## Detection

```yaml
title: Cross Origin Isolation Detection
id: 55df272d-66c2-4b18-af75-70d8a9fae161
status: experimental
description: Detects suspicious activity related to implementing cross origin isolation techniques in browser security context
logsource:
  category: proxy
  product: windows
detection:
  selection:
    cs_uri_query: "*script*"
  condition: selection
level: medium
tags:
  - attack.t1189
  - attack.initial_access
falsepositives:
  - Browser security extensions performing routine URL reputation checks
```


**Detection Opportunities**

| Indicator | Source | Detection Logic |
|---|---|---|
| Cross Origin Isolation Detection | windows/proxy | Sigma rule (medium) |
| ATT&CK Coverage | MITRE ATT&CK | T1189 |

## Verification

- **Verify isolation**: `node scripts/agent.js verify --url https://target.com`
- **Test crossOriginIsolated**: `node scripts/agent.js test --url https://target.com`

## References

- MITRE ATT&CK: T1189
- Frameworks: OWASP, W3C
- Tools: curl, securityheaders, devtools
