Uncontrolled command line¶
ID: rb/command-line-injection Kind: path-problem Severity: error Precision: high Tags: - correctness - security - external/cwe/cwe-078 - external/cwe/cwe-088 Query suites: - ruby-code-scanning.qls - ruby-security-extended.qls - ruby-security-and-quality.qls
Code that passes user input directly to
Kernel.exec, or some other library routine that executes a command, allows the user to execute malicious code.
If possible, use hard-coded string literals to specify the command to run or library to load. Instead of passing the user input directly to the process or library function, examine the user input and then choose among hard-coded string literals.
If the applicable libraries or commands cannot be determined at compile time, then add code to verify that the user input string is safe before using it.
The following example shows code that takes a shell script that can be changed maliciously by a user, and passes it straight to
Kernel.system without examining it first.
class UsersController < ActionController::Base def create command = params[:command] system(command) # BAD end end