Skip to main content

Avant Browser - Same of Origin Policy Bypass - browser:home

Details

Vendor Site: Avant browser (www.avantbrowser.com)
Date: December, 5 2012 – CVE (TBA)
Affected Software: Avant Browser Ultimate 2012 Build 28 and potentially previous versions
Status: Unpatched
Researcher: Roberto Suggi Liverani - @malerisch
PDF version: Avant_multiple_vulnerabilities_advisory.pdf


Same of Origin Policy Bypass

A malicious user can execute arbitrary JavaScript/HTML code on the privileged browser:home page from an untrusted web page on Internet (http:// zone). This is possible by creating an iframe element pointing to the browser:home page and then invoking privileged commands using a window object reference to the iframe element, as shown in the example below:

<iframe name="test2" src="browser:home"></iframe>
<script>window['test2'].navigator.AFRunCommand(id_of_privileged_command, vstr)</script>

This code allows interaction from an untrusted zone (http://) to a trusted and privileged zone: browser:home.

Exploitation

This vulnerability can be exploited in several ways. As the injection point is in the browser: privileged browser zone, it is possible to bypass Same Origin Policy (SOP) protections, and also access Avant Browser native JavaScript privileged functions which can be invoked using the window.navigator object (e.g. window.navigator.*). Such Avant Browser object interfaces can be used to read browser history, bookmarks, or modify Avant Browser configuration. Below, an example of code which allows to read the browser's history is provided.

Exploit - Stealing browser's history

<iframe name="test2" src="browser:home"></iframe>
<script> var vstr = {value: ""}; window['test2'].navigator.AFRunCommand(60003, vstr) alert(vstr.value);
//send vstr.value via an img src to another domain </script>

BeEF module

A BeEF module has been developed which steals history of the Avant browser. The BeEF module can be found below:

https://github.com/malerisch/beef/tree/avant_browser/modules/exploits/avant_steal_history

Video

Avant Browser - BeEF - History Stealing exploit video


Timeline


07/03/2012 - Posted 10 posts to a forum to get a security contact
14/03/2012 - Reception of report confirmed but no further reply
14/03/2012 - Chased them, no reply
03-05/2012 - 2 new releases following the report, one bug silently fixed
12/05/2012 - HITB2012AMS - bug disclosed during presentation
14/11/2012 - HackPra - bug and exploit module presented


Solution

Do not use Avant browser.

Popular posts from this blog

Alcatel Lucent Omnivista or: How I learned GIOP and gained Unauthenticated Remote Code Execution (CVE-2016-9796)

It is time for another advisory or better a blog post about Alcatel Lucent Omnivista  and its vulnerabilities. Omnivista is a central management network tool and it is typically used in medium/large organisation with a complex VoIP/SIP infrastructure. Interestingly enough, this software belongs to the niche of "undownloadable" software and it requires a license to work as well. My "luck" came during an engagement where it was already installed and this post documents one of the many 0days discovered during such audit. The reasons why I wanted to dedicate a single blog post on this vulnerability are several. First, remote code execution (RCE) is always a sweet bug to show. Second, I strongly believe that documenting vulnerabilities in applications using old protocols and standards, respectively GIOP and CORBA, can be beneficial for the infosec community, since no many examples of vulnerabilities in such applications are available or published on the Interne

Microsoft .NET MVC ReDoS (Denial of Service) Vulnerability - CVE-2015-2526 (MS15-101)

Microsoft released a security bulletin ( MS15-101 ) describing a .NET MVC Denial of Service vulnerability ( CVE-2015-2526 ) that I reported back in April. This blog post analyses the vulnerability in details, starting from the theory and then providing a PoC exploit against a MVC web application developed with Visual Studio 2013. For those of you who want to see the bug, you can directly skip to the last part of this post or watch the video directly... ;-) A bit of theory The .NET framework (4.5 tested version) uses backtracking regular expression matcher when performing a match against an expression. Backtracking is based on the NFA (non-deterministic finite automata) algorithm engine which is designed to validate all input states. By providing an “evil” regex expression – an expression for which the engine can be forced to calculate an exponential number of states - it is possible to force the engine to calculate an exponential number of states, leading to a condition defined su

Pwning a thin client in less than two minutes

Have you ever encountered a zero client or a thin client? It looks something like this... If yes, keep reading below, if not, then if you encounter one, you know what you can do if you read below... The model above is a T520, produced by HP - this model and other similar models are typically employed to support a medium/large VDI (Virtual Desktop Infrastructure) enterprise. These clients run a Linux-based HP ThinPro OS by default and I had a chance to play with image version T6X44017 in particular, which is fun to play with it, since you can get a root shell in a very short time without knowing any password... Normally, HP ThinPro OS interface is configured in a kiosk mode, as the concept of a thin/zero client is based on using a thick client to connect to another resource. For this purpose, a standard user does not need to authenticate to the thin client per se and would just need to perform a connection - e.g. VMware Horizon View. The user will eventually authenticat