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- Command injection is an attack

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where you try to execute commands

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that you're not supposed
to be able to execute

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on a system via a vulnerable application.

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Now, command injection
attacks are possible

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whenever an application
doesn't validate any data

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supplied by the user.

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For example, you know, data
that you can enter in web forms,

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in cookies, HTTP headers, and many others.

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Then the system passes
that into a system shell.

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In this attack, you try to
send operating system commands,

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so you can actually cause the
application to execute them

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with the privileges that the application

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is actually running,

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so the vulnerable application is running.

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I want to make sure that you understand

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that this attack is not the same

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as code execution or code injection

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that you see whenever you
exploit a buffer overflow, right?

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Now, command injection is
not a popular attack anymore,

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because a lot of modern
application frameworks

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have a lot better defenses against them.

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Now the folks from the OWASP organization

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have a good reference

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on how command injection actually works,

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in the link that I'm actually
sharing in the screen,

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but in the next lesson

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we will go over a detailed example

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of how actually this works,

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and how to exploit these command
injection vulnerabilities.