FreePBX 'admin/config.php' Remote Code Execution Vulnerability

Summary
FreePBX is prone to a remote code-execution vulnerability.
Impact
Successfully exploiting this issue will allow attackers to execute arbitrary code in the context of the affected application. Failed exploit attempts may result in a denial-of-service condition.
Solution
Updates are available.
Insight
admin/libraries/view.functions.php does not restrict the set of functions accessible to the API handler, which allows remote attackers to execute arbitrary PHP code via the function and args parameters to admin/config.php.
Affected
FreePBX versions 2.9, 2.10, 2.11, and 12 are vulnerable.
Detection
Try to execute a command with a sprecial crafted HTTP GET request.
References