Adding Bytes Using a Hex Editor
You don't need additional software for this, the standard vi installed by macOS can edit binary files.

cd /Applications/Microsoft\ Word.app/Contents/MacOS/
cp Microsoft\ Word Microsoft\ Word.orig
vi -b Microsoft\ Word


Now, assuming you are not used to vi:


Type /app-sandbox followed by Return to jump to the definition you want to change





Press Return again to move the cursor to the next line
Type ct/&lt;false followed by ESC





Type ZZ to save and quit


PS: If you get stuck within vi, press ESC twice and then type :q! to quit without saving.



If you want to script this, use (at our own risk)

vi -b Microsoft\ Word '+/app-sandbox/+1s/true/false/' '+wq'


which basically does the same thing as the interactive sequence above in one go.


/app-sandbox/+1 makes the following command (the substitution) only apply on the line after the one containing the app-sandbox string
s/true/false/ is the substitution and replaces true by false
wq writes the modified file back to disk and quits