what measures should be taken for obtaining browser software to ensure that it hasnt been maliciously modified

Question

please describe the types of risks involved if the browser software is not obtained from a trusted source

Answer 1

Obtain browser software only from the source, or from a trusted download server.

The risks are really minimal, more people are writing malware and adware than rewriting browsers. If you're looking for browser software, the best source for unadulterated copies is from the issuer, or a trusted site such as Download.com or Znet.