Updated Dynamic filtering: Benefits of blocking 3rd party iframe tags (markdown)

Raymond Hill 2015-08-07 09:30:23 -04:00
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### Malware protection
URL: <http://www.riskiq.com/resources/blog/jquerycom-malware-attack-puts-privileged-enterprise-it-accounts-risk>
`iframe` tags are very often used by malware code on compromised web sites. The most recent example of this is ~~[jquery.com](http://blog.jquery.com/2014/09/24/update-on-jquery-com-compromises/)~~ [Firefox's javascript-based PDF reader](https://blog.mozilla.org/security/2015/08/06/firefox-exploit-found-in-the-wild/).
The web site was compromised, and users of the site were served tainted web pages, which could cause a user's browser to download exploit kit from some remote servers. This was done first through a malicious 3rd-party `<script>`, which purpose was to dynamically create and embed a 3rd-party-sourced `<iframe>` on the page.
Using 3rd-party-sourced `<iframe>` to inject exploit on a user's computer is quite a common technique:
- [_"Firefox exploit found in the wild"_](https://blog.mozilla.org/security/2015/08/06/firefox-exploit-found-in-the-wild/)
- [_"jQuery.com Confirms Website Compromise"_](http://www.riskiq.com/blog/business/post/jquerycom-confirms-website-compromise)
- [_"Democracy in Hong Kong Under Attack"_](http://www.volexity.com/blog/?p=33)
- [_"Hackers compromise official PHP website, infect visitors with malware"_](http://arstechnica.com/security/2013/10/hackers-compromise-official-php-website-infect-visitors-with-malware/).
- [_"Feds Are Suspects in New Malware That Attacks Tor Anonymity"_](http://www.wired.com/2013/08/freedom-hosting/)
- [_"willysy.com Mass Injection ongoing, over 8 million infected pages, targets osCommerce sites"_](http://blog.armorize.com/2011/07/willysycom-mass-injection-ongoing.html)
- [_"Firefox exploit found in the wild"_](https://blog.mozilla.org/security/2015/08/06/firefox-exploit-found-in-the-wild/)
- And so on.
<p align="center"><img src="https://cloud.githubusercontent.com/assets/585534/9136475/d8ba8bf6-3ce4-11e5-807c-5346e33c971a.png" /><br><sub><a href="http://www.volexity.com/blog/?p=33">"Compromised Pro-Democratic Hong Kong Websites"</a>, volexity.com.</sub><br><sup>uBlock Origin shown just as a reminder on how to block 3rd-party &lt;iframe&gt; tags.</sup></p>
@ -23,6 +22,8 @@ Simply blocking 3rd-party `<iframe>` by default foils such exploit.
In the above case, blocking 3rd-party scripts would have been even better, as the malicious code would have been prevented from creating the malicious `<iframe>` in the first place. But for users with low tolerance to site breakage, blocking 3rd-party `<iframe>` by default (i.e. on all sites by default) is really the best solution.
Blocking 3rd-party `iframe` tags will typically cause little web page breakage, far less than the more through alternative of blocking 3rd-party javascript, so blocking 3rd-party `iframe` tags is an approach that can work even for less advanced users.
Ultimately, if a site breaks because it really does need legitimate 3rd-party `<iframe>`, then un-blocking `<iframe>` for a specific site is only one click away:
<p align="center"><img src="https://cloud.githubusercontent.com/assets/585534/9136522/4455038c-3ce5-11e5-9e91-e8843f15c143.png" /><br><sup>3rd-party &lt;iframe&gt; tags blocked by default for all sites,<br><b>except</b> for the current site (this was for github.com).</sup></p>