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This file may or may not be up-to-date. For best results but less information, run brakeman --help.

Scanning Options

There are some checks which are not run by default. To run all checks, use:

brakeman -A

Each check will be run in a separate thread by default. To disable this behavior:

brakeman -n

By default, Brakeman scans the current directory. A path can also be specified as a bare argument, like:

brakeman some/path/to/app

But to be even more specific, the -p or --path option may be used:

brakeman -p path/to/app

To suppress informational warnings and just output the report:

brakeman -q

Note all Brakeman output except reports are sent to stderr, making it simple to redirect stdout to a file and just get the report.

By default, Brakeman will return a non-zero exit code if any security warnings are found or scanning errors are encountered. To disable this:

brakeman --no-exit-on-warn --no-exit-on-error

To force Brakeman into Rails 3 mode:

brakeman -3

Or to force Brakeman into Rails 4 mode:

brakeman -4

Beware some behavior and checks rely on knowing the exact version name. This shouldn't be a problem with any modern Rails app using a Gemfile.lock though.

Brakeman used to parse routes.rb and attempt to infer which controller methods are used as actions. However, this is not perfect (especially for Rails 3/4), so now it assumes all controller methods are actions. To disable this behavior:

brakeman --no-assume-routes

While this shouldn't be necessary, it is possible to force Brakeman to assume output is escaped by default:

brakeman --escape-html

If Brakeman is running a bit slow, try

brakeman --faster

This will disable some features, but will probably be much faster (currently it is the same as --skip-libs --no-branching). WARNING: This may cause Brakeman to miss some vulnerabilities.

To disable flow sensitivity in if expressions:

brakeman --no-branching

To instead limit the number of branches tracked for a given value:

brakeman --branch-limit LIMIT

LIMIT should be an integer value. 0 is almost the same as --no-branching but --no-branching is preferred. The default value is 5. Lower values generally make Brakeman go faster. -1 is the same as unlimited.

To skip certain files or directories use:

brakeman --skip-files file1,/path1/,path2/

Directories are matched relative to the root path of your application and must end in a path separator for your platform (ex. /). The above invocation would match and skip the following:

  • Any file named file1. Any file that has file1 as a path component would still be scanned.
  • Any file within /path1. Because of the leading /, only directories from the application's root directory will match. For example, /lib/path1/some_path1_file.rb would still be scanned.
  • Any directory named path2. Because there is no leading /, any directory with path2 as a path component will be skipped. For example, /lib/path2/some_lib_for_testing.rb would not be scanned.

Note Brakeman does "whole program" analysis, therefore skipping a file may affect warning results from more than just that one file.

The inverse but even more dangerous option is to choose specific files or directories to scan:

brakeman --only-files file1,/path2/,path2/

Again, since Brakeman looks at the whole program, it is very likely not going to behave as expected when scanning a subset of files. Also, if certain files are excluded Brakeman may not function at all.

To skip processing of the lib/ directory:

brakeman --skip-libs

To run a subset of checks:

brakeman --test Check1,Check2,etc

To exclude certain checks:

brakeman --except Check1,Check2,etc

Note it is not necessary to include the Check part of the check. For example, these are equivalent:

brakeman --test CheckSQL
brakeman --test SQL

Output Options

To see all kinds of debugging information:

brakeman -d

To specify an output file for the results:

brakeman -o output_file

The output format is determined by the file extension or by using the -f option. Current options are: text, html, tabs, json, markdown and csv.

Multiple output files can be specified:

brakeman -o output.html -o output.json

To specify a CSS stylesheet to use with the HTML report:

brakeman --css-file my_cool_styling

By default, Brakeman will only report a single warning of a given type for the same line of code. This can be disabled using

brakeman --no-combine-locations

To disable highlighting of "dangerous" or "user input" values in warnings:

brakeman --no-highlights

To report controller and route information:

brakeman --routes

However, if you really want to know what routes an app has, use

rake routes

To set the limit on message length in HTML reports, use

brakeman --message-limit LIMIT

The default LIMIT is 100.

To limit width of the tables output in text reports, use

brakeman --table-width LIMIT

By default, there is no limit.

Brakeman will warn about each model without attr_accessible. In the HTML report it may be nicer to get all models in one warning with

brakeman --no-separate-models

Sometimes you don't need a big report, just the summary:

brakeman --summary

Reports show relative paths by default. To use absolute paths instead:

brakeman --absolute-paths

This does not affect HTML or tab-separated reports.

To output Markdown with nice links to files on Github, use

brakeman --github-repo USER/REPO[/PATH][@REF]

For example,

brakeman --github-repo presidentbeef/inject-some-sql

To compare results of a scan with a previous scan, use the JSON output option and then:

brakeman --compare old_report.json

This will output JSON with two lists: one of fixed warnings and one of new warnings.

By default, brakeman opens output in less pager. To have brakeman output directly to terminal, use

brakeman --no-pager

Ignoring Stuff

Brakeman will ignore warnings if configured to do so. By default, it looks for a configuration file in config/brakeman.ignore.

To specify a file to use:

brakeman -i path/to/config.ignore

To create and manage this file, use:

brakeman -I

To ignore possible XSS from model attributes:

brakeman --ignore-model-output

Brakeman will raise warnings on models that use attr_protected. To suppress these warnings:

brakeman --ignore-protected

Brakeman will assume that unknown methods involving untrusted data are dangerous. For example, this would cause a warning (Rails 2):

<%= some_method(:option => params[:input]) %>

To only raise warnings only when untrusted data is being directly used:

brakeman --report-direct

This option is not supported very consistently, though.

To indicate certain methods return properly escaped output and should not be warned about in XSS checks:

brakeman --safe-methods benign_method_escapes_output,totally_safe_from_xss

Brakeman warns about use of user input in URLs generated with link_to. Since Rails does not provide anyway of making these URLs really safe (e.g. limiting protocols to HTTP(S)), safe methods can be ignored with

brakeman --url-safe-methods ensure_safe_protocol_or_something

Confidence Levels

Brakeman assigns a confidence level to each warning. This provides a rough estimate of how certain the tool is that a given warning is actually a problem. Naturally, these ratings should not be taken as absolute truth.

There are three levels of confidence:

  • High - Either this is a simple warning (boolean value) or user input is very likely being used in unsafe ways.
  • Medium - This generally indicates an unsafe use of a variable, but the variable may or may not be user input.
  • Weak - Typically means user input was indirectly used in a potentially unsafe manner.

To only get warnings above a given confidence level:

brakeman -w3

The -w switch takes a number from 1 to 3, with 1 being low (all warnings) and 3 being high (only highest confidence warnings).

Configuration Files

Brakeman options can stored and read from YAML files. To simplify the process of writing a configuration file, the -C option will output the currently set options.

Options passed in on the commandline have priority over configuration files.

The default config locations are ./config/brakeman.yml, ~/.brakeman/config.yml, and /etc/brakeman/config.yml

The -c option can be used to specify a configuration file to use.

Miscellaneous

To list available checks with short descriptions:

brakeman --checks

To show checks which are optional (not run by default):

brakeman --optional-checks

To see Brakeman's version:

brakeman --version

To see the real list of options:

brakeman --help