(0day) Microsoft Windows contact File Insufficient UI Warning Remote Code Execution V

[dr.respect 0]

This vulnerability allows remote attackers to execute arbitrary code on vulnerable installations of Microsoft Windows. User interaction is required to exploit this vulnerability in that the target must visit a malicious page or open a malicious file.

 

The flaw is due to the processing of ".contact" files, the E-mail address field takes an expected E-mail address value, however the .CONTACT file is vulnerable to HTML injection as no validation is performed.

Therefore, if an attacker references an executable file using an HREF tag it will run that instead without warning instead of performing the expected email behavior. This is dangerous and would be unexpected to an end user. The E-mail addresses Mailto: will point to an arbitrary executable like. [email protected] Additionally the executable file can live in a sub-directory and be referenced like "[email protected]" or attackers can use directory traversal techniques to point to a malware say sitting in the targets Downloads directory like: [email protected] Making matters worse is if the the files are compressed then downloaded "mark of the web" (MOTW) may potentially not work as expected using certain archive utils. This advisory was initially one of three different vulnerabilities I reported to Zero Day Initiative Program (ZDI), that microsoft decided to not release a security fix for and close. The first cases I reported to ZDI were .VCF and .CONTACT files Website address input fields.

 

POC:

Create a Windows .CONTACT file and inject the following HTML into the E-mail: field

[email protected]

 

Windows will prompt you like "The e-mail address you have entered is not a valid internet e-mail address. Do you still want to add this address?"

Click Yes.

Open the .CONTACT file and click the Mailto: link BOOM! Windows calculator will execute.

Attacker supplied code is not limited to .EXE, .CPL or .COM as .VBS files will also execute! :)

 

VIDEO:

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