install

Additional install commands

macOS

Homebrewverified · 100%

brew install gsan

local Homebrew formula metadata

Linux

Nixverified · 92%

nix profile install nixpkgs#gsan

nixpkgs package indexes · pkgs/by-name/gs/gsan/package.nix · source: api.github.com

overview

Package summary

Extract subdomains from SSL certificates in HTTPS sites

Project links

Commands and aliases

gsan

history

Project history and usage

GSAN, from the getaltname project, is a small reconnaissance CLI for extracting Subject Alternative Names from HTTPS certificates. Its distinctive point is that it connects directly to servers rather than relying on Certificate Transparency logs.

Project history

The GitHub repository was created in November 2017, and early releases appeared in March 2018. The release stream moved quickly through 0.x and 1.x versions in 2018, reached 3.x during 2018 and 2019, published 4.2.3 in October 2020, and published 5.0.0 in August 2024.

The README and GitHub Pages site present a focused tool: pass a domain or pipe domain and IP:PORT lists into `gsan`, extract DNS names from the certificate SAN extension, and optionally write output for other tools.

Adoption history

GSAN's adoption evidence is narrow but clear: it is packaged for Homebrew and Nix and documented for pipx and Docker use. Its audience is security practitioners doing subdomain enumeration, especially in cases where direct certificate inspection is useful for internal servers, self-signed certificates, or targets not covered by public Certificate Transparency logs.

How it is used

Basic usage is `gsan example.com`, producing the SAN DNS names found in the HTTPS certificate. The documentation also shows piping many targets with xargs, using Docker, combining results from Shodan, applying timeouts, writing an output file, and passing that output to Nmap.

Why package nerds care

GSAN is package-manager interesting as a tiny Python security CLI whose value comes from composing with other tools. It takes certificate metadata, emits target lists, and fits into Unix pipelines with Shodan, xargs, Docker, and Nmap.

Timeline

2017: GitHub repository created.
2018: 0.2.0 through 2.0.0 releases published in March.
2018: 3.0.3 release published in July.
2019: 3.0.13 and v3.0.14 releases published.
2020: v4.2.3 release published.
2024: v5.0.0 release published.

Related projects

Shodan is shown in the README as a source of HTTPS targets for GSAN.
Nmap is shown as a downstream consumer of GSAN output files.
Certificate Transparency log tools are related but differ from GSAN's direct TLS-connection approach.

Sources

security posture

Risk level: blue

broad file, network, media, or database tool signal.

Risk classifier

blue risk · medium confidence · tool

Why

broad file, network, media, or database tool signal

Signals

text:http

Install behavior

No Homebrew post-install hook is recorded in formula metadata.
Homebrew bottle metadata is available for 1 platform targets.
Installs with 2 runtime dependencies.

Recommended review

Before unattended agent use, check whether the tool reads plaintext credentials, writes remote state, publishes artifacts, or shells out to plugins.

executables

Installed executables

Command	Kind	Exposure	Note
`gsan`	cli	global executable

freshness

Version and freshness

These signals separate page generation age, package-manager activity, and upstream release comparison. Version lag is warned only when an evidence URL and comparable versions are present.

page generated2026-07-08

manager version5.0.0

manager updated2026-06-21

local dataok

upstreamnot checked

latest detectednot detected

https://franccesco.github.io/getaltname/

infoRelease/tag comparison is only available for GitHub repositories.https://franccesco.github.io/getaltname/none confidence

install metadata

Package metadata

Package key	brew:gsan
Version	5.0.0
Package manager	Homebrew
Package manager page	https://formulae.brew.sh/formula/gsan
Homepage	https://franccesco.github.io/getaltname/
Repository	https://github.com/franccesco/getaltname
Upstream docs	https://franccesco.github.io/getaltname
License	MIT
Source archive	https://files.pythonhosted.org/packages/73/0c/1fc5a29ae79fd74f0fd54d2c4d487b8cf7b21ede08efe99a6c39977816c6/gsan-5.0.0.tar.gz
Last updated	2026-06-21T14:25:28Z
Pulse	updated
Dependencies	cryptography, python@3.14
Bottle	available (on all)
Homebrew post-install	not defined
Service	none declared

registry facts

Source database details

Source Database	Homebrew formula API
Tap	homebrew/core
Full Name	gsan
Version Scheme	0
Revision	5
Head Version	HEAD
Bottle Stable Root URL	https://ghcr.io/v2/homebrew/core
Deprecated	no
Disabled	no
Keg Only	no
URL Keys	head stable

source database matches

Other package-manager records

Matches are pulled from external package-manager indexes and kept separate from local Automic Vault package links.

Nix95%

gsan

nix profile install nixpkgs#gsan

normalized package name match
Matched by: Gsan

nixpkgs package indexes · api.github.com · nixpkgs package indexes: pkgs/by-name/gs/gsan/package.nix from https://api.github.com/repos/NixOS/nixpkgs/git/trees/master?recursive=1

package graph

Links come from deterministic package relationships, av.db category and tag curation, ecosystem matches, and package hub membership.

source trail

Generated from repository data

This page is generated by av-web from the private package SQLite artifact built by scripts/generate-pkg-sqlite.py.

Combined YAML source

View the package source record on GitHub.

combined/gsan.yml

Used sources

Geiger risk classifier
Nucleus package database
av.db category and tag curation
cross-ecosystem install command graph
curated package history
external package-manager database matches
package relationship graph
package version freshness
package-page enrichment

Install gsan with Homebrew, Nix