Out of Band Command Injection

Summary

Netsparker identified a command injection by capturing a DNS A request, which occurs when input data is interpreted as an operating system command.

This is a highly critical issue and should be addressed as soon as possible.

Impact

An attacker can execute arbitrary commands on the system.

Actions To Take

See the remedy for solution.
If possible, do not invoke system commands from the application.
Find all instances of similar code and make the code changes outlined in the remedy section.

Remediation

Before invoking system commands within an application, consider using an API, which allows you to separate commands and parameters. This can avoid many of the problems associated with command execution. See the external references for some examples. If this is not possible, whitelist all input and encode it in accordance with the underlying subsystem. (e.g. if it is Windows, then you need to escape from cmd.exe control characters)

Required Skills for Successful Exploitation

This is an easy issue to exploit, requiring little skill or knowledge. Most knowledgeable attackers can gain remote access over such a system within minutes.

Classifications

PCI v3.1-6.5.1, PCI v3.2-6.5.1, CAPEC-88, WASC-31, OWASP 2013-A1, OWASP 2017-A1 , CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H

Netsparker Security Insights

Helpful Use Cases