Validate environment variables

[joachimmetz]

Validate environment variables, such as %%environ_systemdrive%% in paths

[joachimmetz]

grep %%environ_ data/* | sed "s/^[^%]*%%/%%/;s/%%[^%]*$/%%/" | sort | uniq
%%environ_allusersappdata%%
%%environ_allusersprofile%%
%%environ_programfiles%%
%%environ_programfilesx86%%
%%environ_systemdrive%%
%%environ_systemroot%%
%%environ_windir%%

Where %%environ_allusersappdata%% does not seem to be a Windows native environment variable
https://en.wikipedia.org/wiki/Environment_variable

[joachimmetz]

To do: determine how GRR uses %%environ_allusersappdata%%

[joachimmetz]

https://github.com/google/grr/blob/8123918157e0c53a2ba36d225cec542c6ee4524d/grr/server/grr_response_server/artifact.py#L102