If you are using this on a machine without internet, ensure you have robust antivirus protection, but understand that unpatched vulnerabilities remain a significant concern. Is MSWord portable legal to use? - Microsoft Q&A
It is vulnerable to exploits if you open a specially crafted file. If you are using this on a machine
Microsoft Office 2007 Portable: Using Word and Excel at 100 MB Microsoft Office 2007 Portable: Using Word and Excel
If you still own an original Office 2007 installation disc and its 25-digit product key, you can legally install it, but it should only be used in an offline environment to prevent security exploits. Office 2007 Minimal Memory Requirements you can legally install it
The file size of the Microsoft Office 2007 Portable Word Excel Only package is approximately 100 MB, which is relatively small compared to the full installation package. The system requirements for running this portable version are: