B603: Test for use of subprocess with shell equals true
Python possesses many mechanisms to invoke an external executable. However, doing so may present a security issue if appropriate care is not taken to sanitize any user provided or variable input.
This plugin test is part of a family of tests built to check for process spawning and warn appropriately. Specifically, this test looks for the spawning of a subprocess without the use of a command shell. This type of subprocess invocation is not vulnerable to shell injection attacks, but care should still be taken to ensure validity of input.
Because this is a lesser issue than that described in subprocess_popen_with_shell_equals_true a LOW severity warning is reported.
This plugin test shares a configuration with others in the same family, namely shell_injection. This configuration is divided up into three sections, subprocess, shell and no_shell. They each list Python calls that spawn subprocesses, invoke commands within a shell, or invoke commands without a shell (by replacing the calling process) respectively.
This plugin specifically scans for methods listed in subprocess section that have shell=False specified.
shell_injection: # Start a process using the subprocess module, or one of its wrappers. subprocess: - subprocess.Popen - subprocess.call
>> Issue: subprocess call - check for execution of untrusted input. Severity: Low Confidence: High Location: ./examples/subprocess_shell.py:23 22 23 subprocess.check_output(['/bin/ls', '-l']) 24
New in version 0.9.0.