How do ensure that one's exit node will not send one JS malware (like the forbes.com drive-by download attack?)
1 Answer
Using TLS (https://..) to visit the site means the exit node cannot tamper with the content, Tor Browser uses HTTPS Everywhere to try and sure that this is the case in as many instances as possible.
Tor Browser also comes with NoScript which would allow you to block any .js from loading and under the privacy and security settings you will find the security slider, which can be adjusted to reduce possible avenues of attack at the cost of possibly stopping some kinds web content from working.
Otherwise it is impossible to stop it from injecting or altering content, however volunteers run scans on exit nodes to look for signs of tampering. Nodes found to be altering or injecting content are given a "BadRelay" flag and ejected from the Tor Network. You can report any relays you see doing this by sending an email to [email protected] to be investigated.