Unsafe reflection method constantize called with parameter value Open
@involvable_class = params[:t].constantize
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Brakeman reports on several cases of remote code execution, in which a user is able to control and execute code in ways unintended by application authors.
The obvious form of this is the use of eval
with user input.
However, Brakeman also reports on dangerous uses of send
, constantize
, and other methods which allow creation of arbitrary objects or calling of arbitrary methods.
Potentially dangerous key allowed for mass assignment Open
params.require(:involvement).permit(:role, :role_label, :case_id, :involvable_id, :involvable_type)
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Mass assignment is a feature of Rails which allows an application to create a record from the values of a hash.
Example:
User.new(params[:user])
Unfortunately, if there is a user field called admin
which controls administrator access, now any user can make themselves an administrator.
attr_accessible
and attr_protected
can be used to limit mass assignment. However, Brakeman will warn unless attr_accessible
is used, or mass assignment is completely disabled.
There are two different mass assignment warnings which can arise. The first is when mass assignment actually occurs, such as the example above. This results in a warning like
Unprotected mass assignment near line 61: User.new(params[:user])
The other warning is raised whenever a model is found which does not use attr_accessible
. This produces generic warnings like
Mass assignment is not restricted using attr_accessible
with a list of affected models.
In Rails 3.1 and newer, mass assignment can easily be disabled:
config.active_record.whitelist_attributes = true
Unfortunately, it can also easily be bypassed:
User.new(params[:user], :without_protection => true)
Brakeman will warn on uses of without_protection
.