Bypassing the blacklist command to execute tips (two)

In the first article, we explore how to bypass the blacklist limit of command execution by using methods such as delimiters. The following is a detailed description:

In the second article, we will discuss how to leverage environment variables to bypass the limitations of blacklists and spaces.

First, let’s look at the situation of the Windows system.

Let's first look at the environment variables:

What should we do if a command execution vulnerability now filters spaces? Please see the picture below:

What have you discovered? We can use the values ​​of the environment variable to get what we want. For example, we now try to bypass spaces to execute the command:

Someone may ask, what if there are no keywords we need in the environment variables? Of course, we can add:

Next, let’s look at the situation of Unix system. Here I am using MacOS for testing.

We found that despite the different settings of environment variables, we were able to use environment variables to achieve the effect of bypassing blacklists:

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