So previously I asked a question about what type of private data can addons extract from my browser :

Can a malicious add-on access internet history and such in Chrome/Firefox?

and it turns out if they simply have a permission to read content of the page I'm visiting which most of them have, then they can simply send it to their server and basically record my history this way (since addons dont need permission to access internet and send data)

now my question is, do popular Internet security programs like Kaspersky and their addons detect this type of malicious activity and stop it?

if not, what should I do? because even if an addon is well known I cant still be sure that its not doing something malicious after their latest update, and I don't have the knowledge to check if they are malicious or not. and I cant simply stop using addons since I need most of them! (but I wont install newly made add-ons with no reputation)

so what is the solution here? how can I make sure that no malicious activity is taking place by firefox/chrome addons, is there any good Internet-security/Anti-Virus/addon that does that?

also do chrome and firefox check addons to make sure they are not malicious before putting them in their websites or not? if so, then how likely is it that they miss a malicious addon?

  • 2
    Even if the AV would help - how would you make sure that the AV itself does not access your history? Or that the browser will not leak these information without any extensions? At the end it boils down to whom you trust - and this is true for browser extensions too. Thus, don't just install any arbitrary extension the same as you hopefully don't install just any arbitrary program. Mar 29, 2019 at 6:22
  • @SteffenUllrich yes but I can trust a well known AV company that has been around for decades a lot more than some add-on developer whom is known just for making an add-on, but my question is why can't there be a AV that checks malicious activities by add-ons? for example just to check if an addon is storing history info somewhere and sending it to a server by real time protection? even if they encrypt it before sending, AV can catch it in real time..
    – Mery Ted
    Mar 29, 2019 at 9:12

1 Answer 1


You cannot trust either FF or Chrome to check addons. They do remove the reported ones, but it may be too late.

One way you could test things is monitor traffic between before and after enabling an addon so you detect if something is wrong.

Another way is to only get trusted ones, the ones already tested by thousands of community members.

Anti-viruses will not help because some addons are specifically designed to transmit encrypted data (proxy addons, encrypted chat addons and so forth). Malwarebytes, for example, has a browser extension, but it's something that prevents from general web-site malware; an addon can transmit encrypted information (just like the actual browser or even the OS can) without you or any AV/Extension/defense being able to detect what is transmitted.

Recent browsers can launch separate privacy modes which by default do not load any addons, so if you want to play something sensitive the safe way, you can always use that option.

  • But why can't AVs capture the transmitted data before encryption? for example can't the real time protection of Anti viruses capture this using dynamic analysis for example if add-on X saves the content of the page/name of url somewhere then encrypts it later and sends it => malicious activity. cant they do this?
    – Mery Ted
    Mar 30, 2019 at 6:30
  • It really depends on the design of the malicious system. Some can 'legally' transmit encrypted data without triggering anything, like many Outlook-compromising ones do for example.
    – Overmind
    Apr 8, 2019 at 8:16

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