Penetration Testing with Kali Linux OffSec

chmod +x find_employee_names.py
kali@kali:~$ 
ls -l find_employee_names.py
-rw
x
r-
x
r-
x
1 kali kali 206 Jun 7 12:31 find_employee_names.py 
kali@kali:~$
./find_employee_names.py
R. Jones 
R. Diggs 
G. Grice 
C. Smith 
C. Woods 
D. Coles 
J. Hunter 
L. Hawkins 
E. Turner 
D. Hill 
Listing 14 - Second attempt after chmod. 
After we gave ourselves permission, we did a quick check with ls to find out if the output would 
change. It did! This time, the output contains the “x” character, indicating that executable 
permission is allowed for all three user classes. 
Next, we ran our script again, and thankfully, we receive the expected output this time. The script 
provided us a list of the current employees. 
Let’s now change it back so that we no longer have permission to execute the file. To add the 
permission, we used chmod +x, so this time, we will use chmod -x. 
kali@kali:~$ 
chmod -x find_employee_names.py
kali@kali:~$ 
./find_employee_names.py
zsh: permission denied: ./find_employee_names.py 
Listing 15 - Putting things back the way they were 
We’re back where we started now with the same error message as before. From this small 
experiment, we should have a very basic understanding of the executable permission bit, the 
chmod tool, and the 
+x
and 
-x
options. 
4.4.2
Going Deeper: Encountering a Strange Problem 
Let’s take a moment to remind ourselves that it is fine if we are not following all of the technical 
steps we’ve been covering. Some of the following examples are specifically included to be 
interesting to students who have a better understanding of Linux. 
Let’s continue to explore and push our learning further. 
We’ll consider the fact that the chmod command itself is just a file. It follows the same rules as 
other files on the system, including the same rules about permissions. It exists in a slightly 
different location (in the /usr/bin/ directory) as our script, but the only reason we are able to run 
the 
chmod +x find_employee_names.py
command at all is because the chmod file has its 
permissions set to allow us to run it as a program. 
Now, let’s ask ourselves an interesting question: since chmod is the tool that allows us to set 
permissions, what would we do if we did not have permission to execute it? 

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Penetration Testing with Kali Linux
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Thankfully, it is not easy to accidentally remove our executable permission for this file. Despite 
this, we’ve done so on our system. 
Let’s explore how to fix our script again. We’ll start with our script that worked previously. 
kali@kali:~$