Avant Browser - Stored Cross Site Scripting - Feed Reader (browser://localhost/lst?*)

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

Stored Cross Site Scripting - Feed Reader (browser://localhost/lst?*)

A malicious user can inject and store arbitrary JavaScript/HTML code via multiple RSS feed elements. Vulnerable elements are the following:

<title> element: JavaScript injection using HTML encoded payload
<link> element: JavaScript injection using javascript: pseudouri ( this is rendered in about:blank zone.)
<description> element: JavaScript injection using HTML encoded payload

The following table shows an example of malicious RSS feed:

<?xml version='1.0' encoding="ISO-8859-1"?>
<rss version='2.0'>
<channel>
<description>Malerisch.net</description>
<link>http://blog.malerisch.net/</link>
<title>Malerisch.net</title>
<item>
<title>browser security><img src=a onerror='alert(1);' ;></title>
<link>javascript:alert(window.location);</link>
<description>07/09/2008 - I have done some research in the area of browser security and presented this argument at the last OWASP NZ meeting.<img src=a onerror='alert(2);';>
</description>
<pubDate>Sun, 07 Sep 2008 12:00:00 GMT</pubDate>
</item>
</channel>
</rss>

Injection is possible in a single case: user views a malicious feed using Avant Feed Reader built-in component.

The Feed Reader is located at feed:// URI scheme (e.g. feed://localhost/browser/avent/rss.xml) Note that the URL of the feed has to be subscribed to be rendered under the feed: uri. Also, the feed:// uri scheme is mapped to browser://localhost/lst?domain.name/path/to/rss.feed.

Exploitation

This vulnerability can be defined as a traditional Stored Cross Site Scripting vulnerability. Although, the injection is rendered within an internal browser zone (mapped to browser://localhost/lst?domain.name/path/to/rss.feed ), invocation of privileged commands appears to not be possible as SOP is correctly applied to the browser:// zone.

Video

Avant Browser - Stored Cross Site Scripting - Feed Reader (browser://localhost/lst?*)

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.

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 ...

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...

malerisch.net

Search This Blog