Faiblesses connexes
CWE-ID |
Nom de la faiblesse |
Source |
CWE-200 |
Exposure of Sensitive Information to an Unauthorized Actor The product exposes sensitive information to an actor that is not explicitly authorized to have access to that information. |
|
Métriques
Métriques |
Score |
Gravité |
CVSS Vecteur |
Source |
V2 |
4.3 |
|
AV:N/AC:M/Au:N/C:P/I:N/A:N |
nvd@nist.gov |
EPSS
EPSS est un modèle de notation qui prédit la probabilité qu'une vulnérabilité soit exploitée.
Score EPSS
Le modèle EPSS produit un score de probabilité compris entre 0 et 1 (0 et 100 %). Plus la note est élevée, plus la probabilité qu'une vulnérabilité soit exploitée est grande.
Percentile EPSS
Le percentile est utilisé pour classer les CVE en fonction de leur score EPSS. Par exemple, une CVE dans le 95e percentile selon son score EPSS est plus susceptible d'être exploitée que 95 % des autres CVE. Ainsi, le percentile sert à comparer le score EPSS d'une CVE par rapport à d'autres CVE.
Informations sur l'Exploit
Exploit Database EDB-ID : 19777
Date de publication : 2012-07-11 22h00 +00:00
Auteur : Adi Cohen
EDB Vérifié : Yes
toStaticHTML: The Second Encounter (CVE-2012-1858)
*HTML Sanitizing Bypass -
*CVE-2012-1858<http://www.cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2012-1858>
Original advisory -
http://blog.watchfire.com/wfblog/2012/07/tostatichtml-the-second-encounter-cve-2012-1858-html-sanitizing-information-disclosure-introduction-t.html
Introduction
The *toStaticHTML* component, which is found in Internet Explorer > 8,
SharePoint and Lync is used to sanitize HTML fragments from dynamic and
potentially malicious content.
If an attacker is able to break the filtering mechanism and pass malicious
code through this function, he/she may be able to perform HTML injection
based attacks (i.e. XSS).
It has been a year since the first
encounter<http://blog.watchfire.com/wfblog/2011/07/tostatichtml-html-sanitizing-bypass.html>
was
published, we've now returned with a new bypass method.
Vulnerability
An attacker is able to create a specially formed CSS that will overcome *
toStaticHTML*'s security logic; therefore, after passing the specially
crafted CSS string through the *toStaticHTML* function, it will contain an
expression that triggers a JavaScript call.
The following JavaScript code demonstrates the vulnerability:
*<script>document.write(toStaticHTML("<style>
div{font-family:rgb('0,0,0)'''}foo');color=expression(alert(1));{}
</style><div>POC</div>"))</script>*
In this case the function's return value would be JavaScript executable:
*<style>
div{font-family:rgb('0,0,0)''';}foo');color=expression(alert(1));{;}</style>
<div>POC</div>*
The reason this code bypasses the filter engine is due to two reasons:
1. The filtering engine allows the string "expression(" to exists in
"non-dangerous" locations within the CSS.
2. A bug in Internet Explorer's CSS parsing engine doesn't properly
terminate strings that are opened inside brackets and closed outside of
them.
When combining these two factors the attacker is able to "confuse" the
filtering mechanism into "thinking" that a string is open when in fact it
is terminated and vice versa. With this ability the attacker can trick the
filtering mechanism into entering a state of the selector context which is
considered safer where in fact the code is just a new declaration of the
same selector, thus breaking the state machine and bypassing the filter.
Impact
Every application that relies on the *toStaticHTML* component to sanitize
user supplied data had probably been vulnerable to XSS.
Remediation
Microsoft has issued several updates to address this vulnerability.
MS12-037 - http://technet.microsoft.com/en-us/security/bulletin/ms12-037
MS12-039 - http://technet.microsoft.com/en-us/security/bulletin/ms12-039
MS12-050 - http://technet.microsoft.com/en-us/security/bulletin/MS12-050
Products Mentioned
Configuraton 0
Microsoft>>Lync >> Version 2010
Microsoft>>Lync >> Version 2010
Microsoft>>Lync >> Version 2010
Microsoft>>Office_communicator >> Version 2007
Configuraton 0
Microsoft>>Internet_explorer >> Version 8
Microsoft>>Windows_2003_server >> Version *
Microsoft>>Windows_7 >> Version *
Microsoft>>Windows_7 >> Version -
Microsoft>>Windows_7 >> Version -
Microsoft>>Windows_7 >> Version -
Microsoft>>Windows_server_2003 >> Version *
Microsoft>>Windows_server_2008 >> Version *
Microsoft>>Windows_server_2008 >> Version *
Microsoft>>Windows_server_2008 >> Version *
Microsoft>>Windows_server_2008 >> Version *
Microsoft>>Windows_vista >> Version *
Microsoft>>Windows_xp >> Version *
Microsoft>>Windows_xp >> Version -
Configuraton 0
Microsoft>>Internet_explorer >> Version 9
Microsoft>>Windows_7 >> Version *
Microsoft>>Windows_7 >> Version *
Microsoft>>Windows_7 >> Version *
Microsoft>>Windows_7 >> Version *
Microsoft>>Windows_7 >> Version -
Microsoft>>Windows_7 >> Version -
Microsoft>>Windows_7 >> Version -
Microsoft>>Windows_server_2008 >> Version *
Microsoft>>Windows_server_2008 >> Version r2
Microsoft>>Windows_vista >> Version *
Microsoft>>Windows_vista >> Version -
Références