A fast and modular scanner for Tor exit relays. The canonical repository (including issue tracker) is at https://gitlab.torproject.org/tpo/network-health/exitmap
Exitmap is a fast and modular Python-based scanner for Tor exit relays. Exitmap modules implement tasks that are run over (a subset of) all exit relays. If you have a background in functional programming, think of exitmap as a
map()interface for Tor exit relays: Modules can perform any TCP-based networking task like fetching a web page, uploading a file, connecting to an SSH server, or joining an IRC channel.
In practice, exitmap is useful to monitor the reliability and trustworthiness of exit relays. The Tor Project uses exitmap to check for false negatives on the Tor Project's check service and to find malicious exit relays. It is easy to develop new modules for exitmap; just have a look at the file HACKING in the doc/ directory or check out one of the existing modules.
Exitmap uses Stem to create circuits to all given exit relays. Each time tor notifies exitmap of an established circuit, a module is invoked for the newly established circuit. Modules can be pure Python scripts or executables. For executables, torsocks is necessary.
Finally, note that exitmap is a network measurement tool and of little use to ordinary Tor users. The Tor Project is already running the tool regularly. More exitmap scans just cause unnecessary network load. The only reason exitmap is publicly available is because its source code and design might be of interest to some.
Exitmap uses the library Stem to communicate with Tor. There are plenty of ways to install Stem. The easiest might be to use pip in combination with the provided requirements.txt file:
$ pip install -r requirements.txt
The only argument exitmap requires is the name of a module. For example, you can run exitmap with the checktest module by running:
$ ./bin/exitmap checktest
The command line output will then show you how Tor bootstraps, the output of the checktest module, and a scan summary. If you don't need three hops and prefer to use two hops with a static first hop, run:
$ ./bin/exitmap --first-hop 1234567890ABCDEF1234567890ABCDEF12345678 checktest
To run the same test over German exit relays only, execute:
$ ./bin/exitmap --country DE --first-hop 1234567890ABCDEF1234567890ABCDEF12345678 checktest
If you want to pause for five seconds in between circuit creations to reduce the load on the Tor network and the scanning destination, run:
$ ./bin/exitmap --build-delay 5 checktest
1234567890ABCDEF1234567890ABCDEF12345678is a pseudo fingerprint that you should replace with an exit relay that you control.
To learn more about all of exitmap's options, run:
$ ./bin/exitmap --help
Exitmap comes with batteries included, providing the following modules:
By default, exitmap tries to read the file .exitmaprc in your home directory. The file accepts all command line options, but you have to replace minuses with underscores. Here is an example:
[Defaults] first_hop = 1234567890ABCDEF1234567890ABCDEF12345678 verbosity = debug build_delay = 1 analysis_dir = /path/to/exitmap_scans
Before submitting pull requests, please make sure that all unit tests pass by running:
$ pip install -r requirements-dev.txt $ py.test --cov-report term-missing --cov-config .coveragerc --cov=src test
Contact: Philipp Winter [email protected]
B369 E7A2 18FE CEAD EB96 8C73 CF70 89E3 D7FD C0D0