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I also want to raise an alarm about a current AV practice, not mentioned in the article: AV products like Bitdefender will MITM your HTTPS connections

I also want to raise an alarm about a current AV practice, not mentioned in the article: AV products like Bitdefender will MITM your HTTPS connections by installing their own root certificates, by default and without warnings In the name of "security", this undermines the very purpose of what HTTPS is about, knowingly endangering their users. And consider that I, a highly technical and security conscious software developer, only noticed it because I saw green icons appearing in my search results and then noticed that Google's SSL certificate is now a fake. And I only noticed it because I know how this shit works and those green icons seemed suspicious. And yes, I'm using the word "fake", because I doubt that companies like Bitdefender have to pass the same certifications as a certificate authority or that they have any deals whatsoever with Google. And it's a serious vulnerability, because their certificate can get stolen and used by malicious software, not to mention you now have to trust a third-party with all of your secure connections, which includes your Google searches exposing your most secret desires, your Facebook and Slack chats, your bank account, everything. A third-party that does not have the scrutiny of your open-source web browser. That's just preposterous and these products only survive because users are gullible and technically illiterate.

disiplus 10y ago
i dont think you understand how this works. they install a root certicicate on your machine and do mitm "attack" so they can scan the urls, and block some attacks (i remember when some forum had embeded a pdf, that had some attack and antivirus blocked it ) also you have installed an application that has a root acces to the pc, if it was mallicius it could do allot more damage. it is ultimately a question of trust. i created and installed my own root certificate because i dont want clicking on the exception if i open a new incognito window, its especialy anoying for websocket connections.
- bad_user 10y ago
  I don't think you understand how HTTPS works. > so they can scan the urls, and block some attacks The purpose of HTTPS is to provide a guarantee that your connection to Google is direct, with no intermediaries, such that (1) only Google knows your search query and (2) you get a guarantee that the received content is from Google. And you get this guarantee from certificate authorities that have a good reputation and that are in business because they've proven they can keep their shit secure. And when one of them violates that trust, the OS / browser vendors can start to invalidate their certificates. AV companies are bypassing it all. The blocking of attacks reasoning is kind of bullshit, because Google's Safe Browsing service and browser extensions maintained by a community like uBlock Origin are doing a better job of warning against potentially malicious websites. There are always vulnerabilities to exploit of course, though it's getting harder for those to pop up due to the modern sandboxing of browsers. However I have yet to see evidence that AV software is doing a better job of catching those, because it's a whack-a-mole game and it's more likely that browser vendors find and fix those vulnerabilities faster than AV companies, because bugs get reported to browser vendors first. And sure, if you have Adobe Reader or Oracle Java installed as plugins in your browser, that's a huge risk, but it's actually easier to uninstall those and browsers have started disallowing plugins. Safari for example is disabling everything by default. The problem with installing their own root certificate is precisely one of trust. Yes, you allow a piece of software to run with root permissions, for as long as you don't see it do stupid shit, like installing a root certificate, at which point all of that trust should be gone. And that is because a custom root certificate that doesn't belong to a competent certificate authority cannot be trusted and will increase the attack surface. This is security 101.
  - ComodoHacker 10y ago
    >The blocking of attacks reasoning is kind of bullshit >I have yet to see evidence that AV software is doing a better job of catching those I wouldn't be so one-sided. Imagine a fresh new variety of ransomware starts spreading. No one can catch it at 0-day, but good AV can catch it at 1-st day (OK, 1-st week) and neither Google nor uBlock or the likes can't.
    - majewsky 10y ago
      Do you have any evidence for these claims? What's the concrete mechanism that allows AVs to observe and react to threats earlier than Google? (Since you allow up to 1 week of reaction time, I'll assume that you're not referring to heuristic detection methods.)
      - ComodoHacker 10y ago
        With cloud reputation service all AV user base (provided sufficiently large) turn into global sensor network, along with honeypots vendors maintain separately. This allows (at the cost of users' privacy) to detect new emerging threats within hours, then acquire samples, analyze them and deploy new signatures within days. Google can of course react equally fast. But "signal delay" may be much higher, as users report only URLs they can immediately link to their troubles, e.g. malware that crash browser. And second, what Google can do now is to block only one attack vector, namely web page. Thinking rationally, chances are high that Google is seriously considering to enter the AV business. They are in highly advantageous position to do it successfully, with their user base, resources and AI tech.
        ltowel 10y ago
        Google owns VirusTotal, so they either alternatively have a strong set of tagged samples to work with, or an incentive to not disrupt their partnerships with exiting vendors.
        10y ago
- zrm 10y ago
  That is a bad idea. If you MITM the connection locally it triples the computational cost for both encryption and handshake operations. Then more websites don't use TLS because it's three times as slow for the user. It also prevents you from using a good cipher suite when the MITM doesn't support it even though the browser and the server both do, again reducing security or performance or both. And it's very easy to screw this up the other way and have the browser show a good secure connection with strong primitives and forward secrecy while the MITM is actually communicating with the server using export ciphers or RC4. The existence of a trusted root private key on your machine exposes you to KCI of all servers. And key compromise is not even necessary if they use the same root private key for everyone, which has actually happened. This is not a comprehensive list of the reasons why that is a bad idea.
  - disiplus 10y ago
    ok some of those are valid concerns but i would argue that being infected trumps all of those. they have to get it only once.
    - zrm 10y ago
      Compromising TLS is an infection vector. People regularly download programs from trusted websites and run them. Some apps automatically download updates from the vendor's site via TLS. AV scanners do not have a 100% detection rate. Letting malware be where a trusted program is expected is how you get infected.
fbis251 10y ago
Don't forget that if their software is changing the certificates for every HTTPS site you visit they're probably doing it on the fly. This means that the private key is on your computer. Assuming they generate a per install private key that won't be a big issue but if it's the same private key for all their installs it could get pretty bad once someone gets the key
billpg 10y ago
Don't most browsers have hooks for AV (and other plugins) to get into web traffic without having to mess with TLS?
- bad_user 10y ago
  No, I don't think so and if it does, please tell me which browser does it so I can keep away from it, because that defeats the purpose of TLS. Either way, Bitdefender installs their own root certificate and generates their own for google.com. I've got proof if you want.
  - tokenizerrr 10y ago
    Chrome, Firefox. Probably more. https://developer.mozilla.org/en-US/docs/Mozilla/Projects/NSS/Key_Log_Format https://developer.mozilla.org/en-US/docs/Mozilla/Projects/NS...
    - hsivonen 10y ago
      That's for the Wireshark debugging use case.
      - tokenizerrr 10y ago
        Indeed it is, yet it can be used for other things as well. Such as an AV that would want to MITM everything without supplying its own CA.
        hsivonen 10y ago
        Is some AV product using it for that?
        mercurialuser 10y ago
        Trend micro officescan, their enterprise offering, has plugins for Firefox. Well, it had a plugin that got disabled by following Firefox updates.
yAnonymous 10y ago
Microsoft doesn't exactly have a great record with root certificates either. >Emergency Windows update revokes dozens of bogus Google, Yahoo SSL certificates https://arstechnica.com/security/2014/07/emergency-windows-update-revokes-dozens-of-bogus-google-yahoo-ssl-certificates/ https://arstechnica.com/security/2014/07/emergency-windows-u... They revoked certs like this silently in the past which makes it even worse.
- josteink 10y ago
  Got an example? I haven't heard anything about this and I'm genuinely curious.
  - yAnonymous 10y ago
    Added a link to the post.
  - provirus 10y ago
    There has been critics on the quietly updating of root certs by Microsoft. https://news.ycombinator.com/item?id=9789819 https://news.ycombinator.com/item?id=9789819
- bad_user 10y ago
  Any references, because I don't know what you're talking about? I'm not a Windows user, haven't been a Windows user since 2001, my AV experience has been with the PCs of my family, whom I'm trying to keep safe. But even if I were a Windows user, if you can't trust Microsoft, you can't trust their OS, at which point it would be better to use something else because security really depends on how trustworthy that OS and its vendor are. I do trust Microsoft more than I trust an AV vendor though.
  - yAnonymous 10y ago
    Added a link to the post.
- kbart 10y ago
akjainaj 10y ago
> In the name of "security", this undermines the very purpose of what HTTPS is about, knowingly endangering their users. It doesn't have to be insecure. If the software that does the MITM checks the certificates correctly, I don't see how it would be worse than letting the browser handle it. Not that I'd ever use an antivirus, of course.
- raesene6 10y ago
  It actually is worse. The problem comes "what does the interception do when it encounters an invalid certificate"? So for example a self-signed cert. does it a) create a "valid" cert itself, hiding the error from the user? This is obviously dangerous b) create an "invalid" self-signed cert. This is messy as a user will then see a self-signed cert from the A-V vendor, which they may be more or less inclined to trust c) Pass the traffic through without inspection, missing any potential threats And that's just one case. SSL/TLS interception is very hard to get right and easy to make the user's security worse as a result.
  - akjainaj 10y ago
    It can simply stop the connection and show the user, under the normal certificate, a message telling him there's a problem with the cert.
    - raesene6 10y ago
      So to do that it's going to stop the users browsing session, redirect them to a local web page and then present something to let them make a decision about carrying on? not the best user experience in the world.. But remember like I said that's just one example of why it's a bad idea, there's others, e.g. what do you do about EV-SSL certificates? You can't fake the browser element for them (remember this is the case where the A-V product hasn't hooked the browser), so where you want to MITM a EV-SSL connection you have to downgrade it to Non-EV. Also what do you do with certificate pinning (either browser in-built or HPKP headers?)
      - 10y ago
noemotion 10y ago
I am not disagreeing with you, but I want to point out that, usually, the certificate is generated locally during setup and then installed in the trusted certificates store. So no one else should have that certificate. I also assume there is an option somewhere to disable the MITM scanner.
- bad_user 10y ago
  > I also assume there is an option somewhere to disable the MITM scanner. By default this is ON and users don't have the competence to recognize that this is in fact increasing the surface area for attacks and to disable it. The mere existence of a setting that is ON by default doesn't absolve such AV companies. But speaking of Bitdefender in particular, I installed it on my wife's computer, disabled that option, confirmed that it survived a restart, then one month later I discovered that it is ON again, probably due to an automatic update. It's also an "admin" setting and my wife's user account does not have admin privileges to turn it on or off. So even with a setting in place, it's untrustworthy.
  - ashmud 10y ago
    Bitdefender likes to revert to default settings frequently. I prefer Windows Firewall (Win7) and have to turn off the Bitdefender firewall usually at least once a week.
    - slrz 10y ago
      What is the reason you're using the software at all? What is it achieving for you? Genuinely interested in the motivations.
  - compuguy 10y ago
    When I was using bitdefender, this was the first setting I disabled after installing it. Bitdefender also has a slew of other issues, including BSODing after installation.
- hrez 10y ago
  Bitdefender free version doesn't have ssl MITM feature. Neither it installs root cert as far as I can see.
tomaskafka 10y ago
Yes. Also, let's finally start a public discussion about AV companies making money by selling data (they do, either all of them or most). Of course that being able to peek into https traffic gets them more data (specific urls, not just whole sites).
- bjd2385 10y ago
  _Everyone_ is collecting our data nowadays. Who's left to sell it to?
  - provirus 10y ago
    But not everyone has access to all of your browsing history; especially across browsers and devices. There's Microsoft, Google, and/or Apple have that. The profit models of these big companies create some disincentives on onselling this data. AV providers are often on much smaller margins and the return from selling this data or building their own products on it is much higher. I wouldn't be surprised if ISPs and VPNs also sold on data.
  - lottin 10y ago
    Not everyone. FOSS doesn't.
    - StreamBright 10y ago
      citation needed https://github.com/Homebrew/brew/blob/master/docs/Analytics.md https://github.com/Homebrew/brew/blob/master/docs/Analytics....
      - AsyncAwait 10y ago
        That link says nothing about selling your data. Also note that while Homebrew may be open-source, it is not "free software".
        clarry 10y ago
hannob 10y ago
I've written and talked about this a couple of times. Each and every one of these products does some kind of TLS security degredation: * https://blog.hboeck.de/archives/869-How-Kaspersky-makes-you-vulnerable-to-the-FREAK-attack-and-other-ways-Antivirus-software-lowers-your-HTTPS-security.html https://blog.hboeck.de/archives/869-How-Kaspersky-makes-you-... * https://media.ccc.de/v/camp2015-6833-tls_interception_considered_harmful https://media.ccc.de/v/camp2015-6833-tls_interception_consid...
xuhu 10y ago
Browsers grudgingly support local MITM as an ugly half-ass solution, mostly because banks require it as part of their data loss prevention measures. Since there is no OS-provided API, there is no alternative that makes corporate clients happy. Depending on the AV vendor, the MITM implementation will "give AV access to your SSL traffic" or "allow everyone to intercept it" (Symantec).
Neil44 10y ago
If the alternative is not scanning ssl traffic for malware then perhaps if it's done correctly then it's not a bad compromise. For example a broken upstream cert should just be treated the same as if malware was detected. I bet good AV would update revocation lists more often than the OS & browser does too.
w8rbt 10y ago
Many corporations do this on their networks so that they can inspect traffic for security purposes and outbound loss prevention. It's not uncommon today and seems to be gaining in popularity. Edit: I don't mean to imply that it's the right or the wrong thing to do (it probably depends on the situation). Just stating what I have seen in industry.
- Terretta 10y ago
  That communication belongs to the company, the session is work product on a company owned device. Feels squeamish if you didn't think about it that way, but is implied by almost every employment agreement. This is quite different than the AV vendor who does not own your communication from your own device.
  - WorldMaker 10y ago
    I still wish most companies knew/had a better "best practice" than just MITM interception certificates, because that is potentially brittle and is an threat to corporate security. If you already have all of your machines MITMed, then an attacker could gain access to the existing MITM certificate and who would ever know. I know I'm a relative minority in the corporate IT world, but as a software developer downloading/uploading dependent libraries or the outputs of my development issues, corporate MITM interception certificates absolutely scare me for my personal threat model and the threat model of the projects that I work on.
    - tyingq 10y ago
      >because that is potentially brittle It is. I do work in a Fortune 500 occasionally, and have to use their MITM gateway (websense SSL intercept). They haven't yet fixed the internal cert to not use SHA-1. If you're using something other than a corporate windows desktop + browser, you have to install the root certificates manually. They have to make manual exceptions for sites that do certificate pinning. When they miss a site, it creates issues. Github is broken for me...I have to use crazy workarounds. If there were a movement to enable certificate pinning everywhere, it would be very disruptive for the Corporate MITM vendors. Edit: They also have irritating "content filters". So, if I'm tasked to research options for a project, like say a VPN, I can't search from their network. It blocks pages talking about VPNS because there's a policy to block "websense proxy avoidance".
hartz 10y ago
I feel like, instead of MITM'ing all TLS connections, antivirus companies could implement this same thing in a browser extension. If good ad blockers can prevent requests for ads from being completed, an antivirus extension should be able to do something similar, without having to tamper with the TLS connection between the browser and the site. That being said, users would probably be much safer if they skipped the antivirus and just installed a decent ad blocker.
- tyingq 10y ago
  At least with Chrome, the extension API doesn't allow you to "peek" into the content. You do have the ability to see the url before it's fetched[1], and block the fetch/redirect. But you can't see the data until it's too late. [1]https://developer.chrome.com/extensions/webRequest#event-onBeforeRequest https://developer.chrome.com/extensions/webRequest#event-onB...
rocqua 10y ago
How does that work with chromes certificate pinning for google? Do they do some runtime modification (e.g. DLL-injection) to disable the check?
- ThisIs_MyName 10y ago
  Cert pinning ignores root certs. This is by design :( >The Chromium browser disables pinning for certificate chains with private root certificates to enable various corporate content inspection scanners and web debugging tools (such as mitmproxy or Fiddler). The RFC 7469 standard recommends disabling pinning violation reports for "user-defined" root certificates, where it is "acceptable" for the browser to disable pin validation.
  - voltagex_ 10y ago
    The alternative would be no Chrome and/or Firefox at my workplace, and many others.
- chopin 10y ago
  It does not work with certificates installed by the user.
krisgenre 10y ago
Ya! I only recently noticed this when Google chrome started marking even gmail.com as insecure on my dad's laptop. Turned out that the Bitdefender license had expired and somehow this made certificate validation to fail?
zzm 10y ago
We recently published a paper on this exact issue and quantify the degree to which AV / corporate middlebox systems degrade the security of HTTPS connections. The tl;dr is that we find an alarming amount of MITM on the public internet (5-10%), mostly due to AV/middleboxes, and they almost always degrade the security of the connection. *https://jhalderm.com/pub/papers/interception-ndss17.pdf https://jhalderm.com/pub/papers/interception-ndss17.pdf
hrez 10y ago
Not to detract from the main point but for Bitdefender specifically ssl MITM looks like a paid feature. Which is ironic. So, just use free version. I am not sure if it sends out all the plain url's though. If anybody knows for sure please let us know.

disiplus 10y ago

i dont think you understand how this works. they install a root certicicate on your machine and do mitm "attack" so they can scan the urls, and block some attacks (i remember when some forum had embeded a pdf, that had some attack and antivirus blocked it ) also you have installed an application that has a root acces to the pc, if it was mallicius it could do allot more damage. it is ultimately a question of trust. i created and installed my own root certificate because i dont want clicking on the exception if i open a new incognito window, its especialy anoying for websocket connections.

bad_user 10y ago
I don't think you understand how HTTPS works. > so they can scan the urls, and block some attacks The purpose of HTTPS is to provide a guarantee that your connection to Google is direct, with no intermediaries, such that (1) only Google knows your search query and (2) you get a guarantee that the received content is from Google. And you get this guarantee from certificate authorities that have a good reputation and that are in business because they've proven they can keep their shit secure. And when one of them violates that trust, the OS / browser vendors can start to invalidate their certificates. AV companies are bypassing it all. The blocking of attacks reasoning is kind of bullshit, because Google's Safe Browsing service and browser extensions maintained by a community like uBlock Origin are doing a better job of warning against potentially malicious websites. There are always vulnerabilities to exploit of course, though it's getting harder for those to pop up due to the modern sandboxing of browsers. However I have yet to see evidence that AV software is doing a better job of catching those, because it's a whack-a-mole game and it's more likely that browser vendors find and fix those vulnerabilities faster than AV companies, because bugs get reported to browser vendors first. And sure, if you have Adobe Reader or Oracle Java installed as plugins in your browser, that's a huge risk, but it's actually easier to uninstall those and browsers have started disallowing plugins. Safari for example is disabling everything by default. The problem with installing their own root certificate is precisely one of trust. Yes, you allow a piece of software to run with root permissions, for as long as you don't see it do stupid shit, like installing a root certificate, at which point all of that trust should be gone. And that is because a custom root certificate that doesn't belong to a competent certificate authority cannot be trusted and will increase the attack surface. This is security 101.
- ComodoHacker 10y ago
  >The blocking of attacks reasoning is kind of bullshit >I have yet to see evidence that AV software is doing a better job of catching those I wouldn't be so one-sided. Imagine a fresh new variety of ransomware starts spreading. No one can catch it at 0-day, but good AV can catch it at 1-st day (OK, 1-st week) and neither Google nor uBlock or the likes can't.
  - majewsky 10y ago
    Do you have any evidence for these claims? What's the concrete mechanism that allows AVs to observe and react to threats earlier than Google? (Since you allow up to 1 week of reaction time, I'll assume that you're not referring to heuristic detection methods.)
    - ComodoHacker 10y ago
      With cloud reputation service all AV user base (provided sufficiently large) turn into global sensor network, along with honeypots vendors maintain separately. This allows (at the cost of users' privacy) to detect new emerging threats within hours, then acquire samples, analyze them and deploy new signatures within days. Google can of course react equally fast. But "signal delay" may be much higher, as users report only URLs they can immediately link to their troubles, e.g. malware that crash browser. And second, what Google can do now is to block only one attack vector, namely web page. Thinking rationally, chances are high that Google is seriously considering to enter the AV business. They are in highly advantageous position to do it successfully, with their user base, resources and AI tech.
      - ltowel 10y ago
        Google owns VirusTotal, so they either alternatively have a strong set of tagged samples to work with, or an incentive to not disrupt their partnerships with exiting vendors.
        10y ago
zrm 10y ago
That is a bad idea. If you MITM the connection locally it triples the computational cost for both encryption and handshake operations. Then more websites don't use TLS because it's three times as slow for the user. It also prevents you from using a good cipher suite when the MITM doesn't support it even though the browser and the server both do, again reducing security or performance or both. And it's very easy to screw this up the other way and have the browser show a good secure connection with strong primitives and forward secrecy while the MITM is actually communicating with the server using export ciphers or RC4. The existence of a trusted root private key on your machine exposes you to KCI of all servers. And key compromise is not even necessary if they use the same root private key for everyone, which has actually happened. This is not a comprehensive list of the reasons why that is a bad idea.
- disiplus 10y ago
  ok some of those are valid concerns but i would argue that being infected trumps all of those. they have to get it only once.
  - zrm 10y ago
    Compromising TLS is an infection vector. People regularly download programs from trusted websites and run them. Some apps automatically download updates from the vendor's site via TLS. AV scanners do not have a 100% detection rate. Letting malware be where a trusted program is expected is how you get infected.

fbis251 10y ago

Don't forget that if their software is changing the certificates for every HTTPS site you visit they're probably doing it on the fly. This means that the private key is on your computer. Assuming they generate a per install private key that won't be a big issue but if it's the same private key for all their installs it could get pretty bad once someone gets the key

billpg 10y ago

Don't most browsers have hooks for AV (and other plugins) to get into web traffic without having to mess with TLS?

bad_user 10y ago
No, I don't think so and if it does, please tell me which browser does it so I can keep away from it, because that defeats the purpose of TLS. Either way, Bitdefender installs their own root certificate and generates their own for google.com. I've got proof if you want.
- tokenizerrr 10y ago
  Chrome, Firefox. Probably more. https://developer.mozilla.org/en-US/docs/Mozilla/Projects/NSS/Key_Log_Format https://developer.mozilla.org/en-US/docs/Mozilla/Projects/NS...
  - hsivonen 10y ago
    That's for the Wireshark debugging use case.
    - tokenizerrr 10y ago
      Indeed it is, yet it can be used for other things as well. Such as an AV that would want to MITM everything without supplying its own CA.
      - hsivonen 10y ago
        Is some AV product using it for that?
        mercurialuser 10y ago
        Trend micro officescan, their enterprise offering, has plugins for Firefox. Well, it had a plugin that got disabled by following Firefox updates.

yAnonymous 10y ago

Microsoft doesn't exactly have a great record with root certificates either. >Emergency Windows update revokes dozens of bogus Google, Yahoo SSL certificates https://arstechnica.com/security/2014/07/emergency-windows-update-revokes-dozens-of-bogus-google-yahoo-ssl-certificates/ https://arstechnica.com/security/2014/07/emergency-windows-u... They revoked certs like this silently in the past which makes it even worse.

josteink 10y ago
Got an example? I haven't heard anything about this and I'm genuinely curious.
- yAnonymous 10y ago
  Added a link to the post.
- provirus 10y ago
  There has been critics on the quietly updating of root certs by Microsoft. https://news.ycombinator.com/item?id=9789819 https://news.ycombinator.com/item?id=9789819
bad_user 10y ago
Any references, because I don't know what you're talking about? I'm not a Windows user, haven't been a Windows user since 2001, my AV experience has been with the PCs of my family, whom I'm trying to keep safe. But even if I were a Windows user, if you can't trust Microsoft, you can't trust their OS, at which point it would be better to use something else because security really depends on how trustworthy that OS and its vendor are. I do trust Microsoft more than I trust an AV vendor though.
- yAnonymous 10y ago
  Added a link to the post.
kbart 10y ago

akjainaj 10y ago

> In the name of "security", this undermines the very purpose of what HTTPS is about, knowingly endangering their users. It doesn't have to be insecure. If the software that does the MITM checks the certificates correctly, I don't see how it would be worse than letting the browser handle it. Not that I'd ever use an antivirus, of course.

raesene6 10y ago
It actually is worse. The problem comes "what does the interception do when it encounters an invalid certificate"? So for example a self-signed cert. does it a) create a "valid" cert itself, hiding the error from the user? This is obviously dangerous b) create an "invalid" self-signed cert. This is messy as a user will then see a self-signed cert from the A-V vendor, which they may be more or less inclined to trust c) Pass the traffic through without inspection, missing any potential threats And that's just one case. SSL/TLS interception is very hard to get right and easy to make the user's security worse as a result.
- akjainaj 10y ago
  It can simply stop the connection and show the user, under the normal certificate, a message telling him there's a problem with the cert.
  - raesene6 10y ago
    So to do that it's going to stop the users browsing session, redirect them to a local web page and then present something to let them make a decision about carrying on? not the best user experience in the world.. But remember like I said that's just one example of why it's a bad idea, there's others, e.g. what do you do about EV-SSL certificates? You can't fake the browser element for them (remember this is the case where the A-V product hasn't hooked the browser), so where you want to MITM a EV-SSL connection you have to downgrade it to Non-EV. Also what do you do with certificate pinning (either browser in-built or HPKP headers?)
    - 10y ago

noemotion 10y ago

I am not disagreeing with you, but I want to point out that, usually, the certificate is generated locally during setup and then installed in the trusted certificates store. So no one else should have that certificate. I also assume there is an option somewhere to disable the MITM scanner.

bad_user 10y ago
> I also assume there is an option somewhere to disable the MITM scanner. By default this is ON and users don't have the competence to recognize that this is in fact increasing the surface area for attacks and to disable it. The mere existence of a setting that is ON by default doesn't absolve such AV companies. But speaking of Bitdefender in particular, I installed it on my wife's computer, disabled that option, confirmed that it survived a restart, then one month later I discovered that it is ON again, probably due to an automatic update. It's also an "admin" setting and my wife's user account does not have admin privileges to turn it on or off. So even with a setting in place, it's untrustworthy.
- ashmud 10y ago
  Bitdefender likes to revert to default settings frequently. I prefer Windows Firewall (Win7) and have to turn off the Bitdefender firewall usually at least once a week.
  - slrz 10y ago
    What is the reason you're using the software at all? What is it achieving for you? Genuinely interested in the motivations.
- compuguy 10y ago
  When I was using bitdefender, this was the first setting I disabled after installing it. Bitdefender also has a slew of other issues, including BSODing after installation.
hrez 10y ago
Bitdefender free version doesn't have ssl MITM feature. Neither it installs root cert as far as I can see.

tomaskafka 10y ago

Yes. Also, let's finally start a public discussion about AV companies making money by selling data (they do, either all of them or most). Of course that being able to peek into https traffic gets them more data (specific urls, not just whole sites).

bjd2385 10y ago
_Everyone_ is collecting our data nowadays. Who's left to sell it to?
- provirus 10y ago
  But not everyone has access to all of your browsing history; especially across browsers and devices. There's Microsoft, Google, and/or Apple have that. The profit models of these big companies create some disincentives on onselling this data. AV providers are often on much smaller margins and the return from selling this data or building their own products on it is much higher. I wouldn't be surprised if ISPs and VPNs also sold on data.
- lottin 10y ago
  Not everyone. FOSS doesn't.
  - StreamBright 10y ago
    citation needed https://github.com/Homebrew/brew/blob/master/docs/Analytics.md https://github.com/Homebrew/brew/blob/master/docs/Analytics....
    - AsyncAwait 10y ago
      That link says nothing about selling your data. Also note that while Homebrew may be open-source, it is not "free software".
      - clarry 10y ago

hannob 10y ago

I've written and talked about this a couple of times. Each and every one of these products does some kind of TLS security degredation: * https://blog.hboeck.de/archives/869-How-Kaspersky-makes-you-vulnerable-to-the-FREAK-attack-and-other-ways-Antivirus-software-lowers-your-HTTPS-security.html https://blog.hboeck.de/archives/869-How-Kaspersky-makes-you-... * https://media.ccc.de/v/camp2015-6833-tls_interception_considered_harmful https://media.ccc.de/v/camp2015-6833-tls_interception_consid...

xuhu 10y ago

Browsers grudgingly support local MITM as an ugly half-ass solution, mostly because banks require it as part of their data loss prevention measures. Since there is no OS-provided API, there is no alternative that makes corporate clients happy. Depending on the AV vendor, the MITM implementation will "give AV access to your SSL traffic" or "allow everyone to intercept it" (Symantec).

Neil44 10y ago

If the alternative is not scanning ssl traffic for malware then perhaps if it's done correctly then it's not a bad compromise. For example a broken upstream cert should just be treated the same as if malware was detected. I bet good AV would update revocation lists more often than the OS & browser does too.

w8rbt 10y ago

Many corporations do this on their networks so that they can inspect traffic for security purposes and outbound loss prevention. It's not uncommon today and seems to be gaining in popularity. Edit: I don't mean to imply that it's the right or the wrong thing to do (it probably depends on the situation). Just stating what I have seen in industry.

Terretta 10y ago
That communication belongs to the company, the session is work product on a company owned device. Feels squeamish if you didn't think about it that way, but is implied by almost every employment agreement. This is quite different than the AV vendor who does not own your communication from your own device.
- WorldMaker 10y ago
  I still wish most companies knew/had a better "best practice" than just MITM interception certificates, because that is potentially brittle and is an threat to corporate security. If you already have all of your machines MITMed, then an attacker could gain access to the existing MITM certificate and who would ever know. I know I'm a relative minority in the corporate IT world, but as a software developer downloading/uploading dependent libraries or the outputs of my development issues, corporate MITM interception certificates absolutely scare me for my personal threat model and the threat model of the projects that I work on.
  - tyingq 10y ago
    >because that is potentially brittle It is. I do work in a Fortune 500 occasionally, and have to use their MITM gateway (websense SSL intercept). They haven't yet fixed the internal cert to not use SHA-1. If you're using something other than a corporate windows desktop + browser, you have to install the root certificates manually. They have to make manual exceptions for sites that do certificate pinning. When they miss a site, it creates issues. Github is broken for me...I have to use crazy workarounds. If there were a movement to enable certificate pinning everywhere, it would be very disruptive for the Corporate MITM vendors. Edit: They also have irritating "content filters". So, if I'm tasked to research options for a project, like say a VPN, I can't search from their network. It blocks pages talking about VPNS because there's a policy to block "websense proxy avoidance".

hartz 10y ago

I feel like, instead of MITM'ing all TLS connections, antivirus companies could implement this same thing in a browser extension. If good ad blockers can prevent requests for ads from being completed, an antivirus extension should be able to do something similar, without having to tamper with the TLS connection between the browser and the site. That being said, users would probably be much safer if they skipped the antivirus and just installed a decent ad blocker.

tyingq 10y ago
At least with Chrome, the extension API doesn't allow you to "peek" into the content. You do have the ability to see the url before it's fetched[1], and block the fetch/redirect. But you can't see the data until it's too late. [1]https://developer.chrome.com/extensions/webRequest#event-onBeforeRequest https://developer.chrome.com/extensions/webRequest#event-onB...

rocqua 10y ago

How does that work with chromes certificate pinning for google? Do they do some runtime modification (e.g. DLL-injection) to disable the check?

ThisIs_MyName 10y ago
Cert pinning ignores root certs. This is by design :( >The Chromium browser disables pinning for certificate chains with private root certificates to enable various corporate content inspection scanners and web debugging tools (such as mitmproxy or Fiddler). The RFC 7469 standard recommends disabling pinning violation reports for "user-defined" root certificates, where it is "acceptable" for the browser to disable pin validation.
- voltagex_ 10y ago
  The alternative would be no Chrome and/or Firefox at my workplace, and many others.
chopin 10y ago
It does not work with certificates installed by the user.

krisgenre 10y ago

Ya! I only recently noticed this when Google chrome started marking even gmail.com as insecure on my dad's laptop. Turned out that the Bitdefender license had expired and somehow this made certificate validation to fail?

zzm 10y ago

We recently published a paper on this exact issue and quantify the degree to which AV / corporate middlebox systems degrade the security of HTTPS connections. The tl;dr is that we find an alarming amount of MITM on the public internet (5-10%), mostly due to AV/middleboxes, and they almost always degrade the security of the connection. *https://jhalderm.com/pub/papers/interception-ndss17.pdf https://jhalderm.com/pub/papers/interception-ndss17.pdf

hrez 10y ago

Not to detract from the main point but for Bitdefender specifically ssl MITM looks like a paid feature. Which is ironic. So, just use free version. I am not sure if it sends out all the plain url's though. If anybody knows for sure please let us know.