security enabled verified medium v1.0.0

h2csmuggler

HTTP/2 cleartext smuggling tool that exploits connection upgrade to smuggle requests through reverse proxies and load balancers.

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h2csmuggler {flag-x} {flag-wait} {flag-proxy} {target}

📎 flag-x 📎 flag-wait 📎 flag-proxy 📎 target

h2csmuggler {flag-x} {flag-wait} {flag-proxy} {target}

Sandbox: execFile · Timeout: 120s

Capabilities

web.smuggle.h2c

web.smuggle.detect

web.protocol.h2c-upgrade

Parameters

Name	Type	Required	Default	Description	Aliases
`target`	string	Yes	-	Target URL or host:port	-
`flag-x`	boolean	No	-	Check all smuggling variants	`-x`, `--check-all`
`flag-wait`	integer	No	-	Wait time in seconds between requests	`-w`, `--wait`
`flag-proxy`	string	No	-	HTTP proxy to use	`-p`, `--proxy`

Artifacts

Type	Description	MIME	Schema	Trust
`web.smuggling.report`	h2c smuggling scan results	text/plain	-	verified

Contract

Inputs

web.target.url

Target web server URL

Outputs

web.smuggling.report

Scan results for h2c smuggling

Side effects: network_traffic

Workflow Edges

Produces

web.smuggling.report

Consumes

web.target.url

Resource Profile

Resource	Value
CPU	low
Memory	64 MB
Network	low
Disk I/O	low

Examples

Basic h2c smuggling test

h2csmuggler https://example.com

Check all smuggling variants

h2csmuggler -x https://example.com

Use proxy for testing

h2csmuggler -p http://127.0.0.1:8080 https://example.com

Documentation

h2csmuggler — HTTP/2 Cleartext Smuggling

h2csmuggler is a tool from Bishop Fox for detecting HTTP/2 cleartext (h2c) smuggling vulnerabilities. It exploits the HTTP/1.1 to HTTP/2 upgrade mechanism to smuggle requests through reverse proxies and load balancers.

Usage

# Basic test
h2csmuggler https://example.com

# Check all variants
h2csmuggler -x https://example.com

# Through proxy
h2csmuggler -p http://127.0.0.1:8080 https://example.com

Dependencies

python3

Related Tools

smugglerburpsuitenmap

References

h2csmuggler GitHub