Spyware used by governments poses as Firefox, and Mozilla is angry

There is absolutely no risk of Firefox Portable downloaded from here being affected by this.

According to the article this spyware merely masquerades as Firefox (using its icon, file description, etc.) to fool end users into thinking the program is trustworthy when they see it in their filesystem.

The spyware itself is not actually a browser and it also cannot infect Firefox in any way, so you've got nothing to worry about.

Gamma International sells the spyware to governments. It's not like a virus or anything in the sense that it distributes itself without user intervention, rather its an actual program that infringes on Mozilla's trademarks in order to fool users who work for the government buyers to use it like their normal browser so they can be spied on unknowingly. So unless John signs a deal with the devil, you can be sure every copy of Firefox Portable is built from the legitimate Firefox.

Also afaik mozilla always signs firefox.exe, so you can go to the properties and choose the Digital Signatures tab at the top to see if it's signed by Mozilla Corporation and if its not or if there is no Digital Signatures tab then it's not the real firefox made by Mozilla.