This cop checks if the length of a method exceeds some maximum value. Comment lines can optionally be ignored. The maximum allowed length is configurable.

Cognitive Complexity

Cognitive Complexity is a measure of how difficult a unit of code is to intuitively understand. Unlike Cyclomatic Complexity, which determines how difficult your code will be to test, Cognitive Complexity tells you how difficult your code will be to read and comprehend.

A method's cognitive complexity is based on a few simple rules:

• Code is not considered more complex when it uses shorthand that the language provides for collapsing multiple statements into one
• Code is considered more complex for each "break in the linear flow of the code"
• Code is considered more complex when "flow breaking structures are nested"

Further reading

• Cognitive Complexity docs
• Cognitive Complexity: A new way of measuring understandability

Injection is #1 on the 2013 OWASP Top Ten web security risks. SQL injection is when a user is able to manipulate a value which is used unsafely inside a SQL query. This can lead to data leaks, data loss, elevation of privilege, and other unpleasant outcomes.

Brakeman focuses on ActiveRecord methods dealing with building SQL statements.

A basic (Rails 2.x) example looks like this:

User.first(:conditions => "username = '#{params[:username]}'")

Brakeman would produce a warning like this:

Possible SQL injection near line 30: User.first(:conditions => ("username = '#{params[:username]}'"))

The safe way to do this query is to use a parameterized query:

User.first(:conditions => ["username = ?", params[:username]])

Brakeman also understands the new Rails 3.x way of doing things (and local variables and concatenation):

username = params[:user][:name].downcase
password = params[:user][:password]

User.first.where("username = '" + username + "' AND password = '" + password + "'")

This results in this kind of warning:

Possible SQL injection near line 37:
User.first.where((((("username = '" + params[:user][:name].downcase) + "' AND password = '") + params[:user][:password]) + "'"))

See the Ruby Security Guide for more information and Rails-SQLi.org for many examples of SQL injection in Rails.

Injection is #1 on the 2013 OWASP Top Ten web security risks. SQL injection is when a user is able to manipulate a value which is used unsafely inside a SQL query. This can lead to data leaks, data loss, elevation of privilege, and other unpleasant outcomes.

Brakeman focuses on ActiveRecord methods dealing with building SQL statements.

A basic (Rails 2.x) example looks like this:

User.first(:conditions => "username = '#{params[:username]}'")

Brakeman would produce a warning like this:

Possible SQL injection near line 30: User.first(:conditions => ("username = '#{params[:username]}'"))

The safe way to do this query is to use a parameterized query:

User.first(:conditions => ["username = ?", params[:username]])

Brakeman also understands the new Rails 3.x way of doing things (and local variables and concatenation):

username = params[:user][:name].downcase
password = params[:user][:password]

User.first.where("username = '" + username + "' AND password = '" + password + "'")

This results in this kind of warning:

Possible SQL injection near line 37:
User.first.where((((("username = '" + params[:user][:name].downcase) + "' AND password = '") + params[:user][:password]) + "'"))

See the Ruby Security Guide for more information and Rails-SQLi.org for many examples of SQL injection in Rails.

Injection is #1 on the 2013 OWASP Top Ten web security risks. SQL injection is when a user is able to manipulate a value which is used unsafely inside a SQL query. This can lead to data leaks, data loss, elevation of privilege, and other unpleasant outcomes.

Brakeman focuses on ActiveRecord methods dealing with building SQL statements.

A basic (Rails 2.x) example looks like this:

User.first(:conditions => "username = '#{params[:username]}'")

Brakeman would produce a warning like this:

Possible SQL injection near line 30: User.first(:conditions => ("username = '#{params[:username]}'"))

The safe way to do this query is to use a parameterized query:

User.first(:conditions => ["username = ?", params[:username]])

Brakeman also understands the new Rails 3.x way of doing things (and local variables and concatenation):

username = params[:user][:name].downcase
password = params[:user][:password]

User.first.where("username = '" + username + "' AND password = '" + password + "'")

This results in this kind of warning:

Possible SQL injection near line 37:
User.first.where((((("username = '" + params[:user][:name].downcase) + "' AND password = '") + params[:user][:password]) + "'"))

See the Ruby Security Guide for more information and Rails-SQLi.org for many examples of SQL injection in Rails.

This cop checks for uses of class variables. Offenses are signaled only on assignment to class variables to reduce the number of offenses that would be reported.