Skip to main content

Maxthon - Cross Context Scripting (XCS) - Bookmark Toolbar and Bookmark Sidebar


Vendor Site: Maxthon (
Date: December, 5 2012 – CVE (TBA)
Affected Software: Maxthon and previous versions
Status: Patched
Researcher: Roberto Suggi Liverani - @malerisch
PDF version: Maxthon_multiple_vulnerabilities_advisory.pdf

Cross Context Scripting

Cross Context Scripting  (XCS) is a particular code injection attack vector where the injection occurs from an untrusted zone (e.g. Internet) into a privileged browser zone. In this case, it is possible to inject arbitrary JavaScript/HTML code from an untrusted page into Maxthon browser privileged zone - mx://res/*.


It is possible to inject JavaScript/HTML payload via the “title” parameter of the “Add to Favorites” form. In Maxthon, bookmark UI security controls are weak and allow a trivial exploitation, even for an attentive user, considering the following factors:
  • window.external.addFavorite() can be invoked in an automated fashion;
  • The title entry can be tailored to hide the injection payload;
  • URL of the bookmark can remain legitimate: e.g.
The following screen shot shows an innocuous looking bookmark title and URL. The URL is correct but the title element contains malicious JavaScript code which is not visible directly.

The injected code is rendered at mx://res/sidebar/favorites/index.htm 

Injection occurs under the following conditions/actions:
  • User opens the Favorites sidebar on the left (just clicking on the Star icon, without clicking the malicious bookmark);
  • User clicks on the bookmark link from the bookmark toolbar;
  • User navigates to another tab after having added the malicious bookmark.


This vulnerability can be exploited in several ways. As the injection point is in the mx://res/ privileged browser zone, it is possible to bypass Same Origin Policy (SOP) protections, and also access Maxthon native JavaScript privileged functions which can be invoked from the Maxthon DOM object (e.g. maxthon.*). Such Maxthon object interfaces can be used to read and write from the file system, as well as execute arbitrary commands, steal stored passwords, or modify Maxthon configuration.

Malicious Add to Favorite Injection – HTML Source Code

padding="Google -"
padding2="                      "
padding3=" - the best search engine - bookmark now!!!"
window.external.addFavorite("",padding+"'><scri"+"pt>"+evilpayload+"</"+"script>"+" "+" "+padding+padding3)

<h3>Maxthon - Cross Context Scripting via Bookmark (title parameter) - Code Execution PoC</h3>
<font size="+1">Roberto Suggi Liverani - <a href=""></a> - <a href="">@malerisch</a></font>
<li>User is prompted to bookmark an innocuous looking bookmark, like the one shown in the middle of the screen. The injected payload can only be seen if the user scrolls on the left of the title element.
<li>User adds the bookmark.
<li>User then clicks on the Star (Favorites) icon or
<li>User clicks on the bookmark link from the bookmark toolbar.
<li>In both cases, calc.exe is executed.
The code for the exploit:<br>


Maxthon - Cross Context Scripting (XCS) -  Bookmark Toolbar and Bookmark Sidebar


13/02/2012 - Bug reported to multiple contacts
21/02/2012 - Reception of report confirmed but no further reply
21/02/2012 - Chased vendors - no reply
12/05/2012 - HITB2012AMS - bug disclosed during presentation
02/11/2012 - 25 new releases following the report – 2 bugs silently fixed
14/11/2012 - HackPra - bug and exploit module presented


Do not use Maxthon browser.

Popular posts from this blog

TrendMicro ScanMail for Microsoft Exchange (SMEX) predictable session token - CVE-2015-3326

It's time for another advisory ( CVE-2015-3326 ), a simple one, for a vulnerability which can be found quickly and trivially. For those of you who just want to give a glance at the post, I suggest to directly watch the picture which says it all! The following vulnerability was discovered on TrendMicro SMEX (ScanMail for Microsoft Exchange) 10 SP2 but it affects other versions as well. While surfing the SMEX web administrative interface using a web proxy, I have noticed something in the HTTP request - the session token itself and its format, a number. After observing a significant number of logins, the session token was always represented with an number composed of minimum 4 digits and maximum 5 digits, as shown in the screen shot below:   Although the observed session tokens were never generated sequentially, the lack of a cryptographically strong PRNG for the session identifier, allows a malicious user to trivially guess the token. This attack can be easily automated.

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