ManageEngine ADSelfService Build prior to 6003 - Remote Code Execution (Unauthenticated)

# Exploit Title: ManageEngine ADSelfService Plus 6000 – Unauthenticated Remote Code Execution
# Date: 2020-08-08
# Exploit Author: Bhadresh Patel
# Vendor link: https://www.manageengine.com/company.html
# Version: ADSelfService Plus build < 6003
# CVE : CVE-2020-11552

This is an article with PoC exploit video of ManageEngine ADSelfService
Plus – Unauthenticated Remote Code Execution Vulnerability

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Title:
====
ManageEngine ADSelfService Plus – Unauthenticated Remote Code Execution
Vulnerability

CVE ID:
=======

CVE-2020-11552

Date:
====
08/08/2020 (dd/mm/yyyy)

Vendor:
======
As the IT management division of Zoho Corporation, ManageEngine prioritizes
flexible solutions that work for all businesses, regardless of size or
budget.

ManageEngine crafts comprehensive IT management software with a focus on
making your job easier. Our 90+ products and free tools cover everything
your IT needs, at prices you can afford.

From network and device management to security and service desk software,
we're bringing IT together for an integrated, overarching approach to
optimize your IT.

Vendor link: https://www.manageengine.com/company.html


Vulnerable Product:
==============
ManageEngine ADSelfService Plus is an integrated self-service password
management and single sign on solution. This solution helps domain users
perform self-service password reset, self-service account unlock, employee
self-update of personal details (e.g., mobile numbers and photos) in
Microsoft Windows Active Directory. ADSelfService Plus also provides users
with secure, one-click access to all SAML-supported enterprise
applications, including Office 365, Salesforce, and G Suite, through Active
Directory-based single sign-on (SSO). For improved security, ADSelfService
Plus offers Windows two-factor authentication for all remote and local
logins. Administrators find it easy to automate password resets, account
unlocks while optimizing IT expenses associated with help desk calls.

Product link:
https://www.manageengine.com/products/self-service-password/?meadsol

Abstract:
=======
A remote code execution vulnerability exists in ManageEngine ADSelfService
Plus Software when it does not properly enforce user privileges associated
with Windows Certificate Dialog.
This vulnerability could allow an unauthenticated attacker to remotely
execute commands with system level privileges on target windows host. An
attacker does not require any privilege on the target system in order to
exploit this vulnerability.

Report-Timeline:
=============
27/02/2020: Vendor notified
27/02/2020: Vendor response
28/02/2020: Marked duplicate
11/03/2020: Patch released
23/03/2020: Vendor responded regarding patch release update
26/03/2020: Patch tested and found that it partially fixed the issue.
Reported back to the vendor.
18/04/2020: Shared updated report with new PoC
22/04/2020: Vendor acknowledged the issue
24/07/2020: Patch released (
https://pitstop.manageengine.com/portal/en/community/topic/adselfservice-plus-6003-release-faceid-support
)
08/08/2020: Public disclosure


Affected Software Version:
=============
< ADSelfService Plus build 6003

Exploitation-Technique:
===================
Remote

Severity Rating (CVSS):
===================
9.8 (Critical) (CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H)

Details:
=======
A remote code execution vulnerability exists in ManageEngine ADSelfService
Plus Software when it does not properly enforce user privileges associated
with Windows Certificate Dialog.

This vulnerability could allow an unauthenticated attacker to remotely
execute commands with system level privileges on target windows host. An
attacker does not require any privilege on the target system in order to
exploit this vulnerability.

ManageEngine ADSelfService Plus thick client enables a user to perform
self-service like password reset, self-service account unlock, etc by using
self-service option on windows login screen.

Upon selecting this option, ManageEngine ADSelfService Plus thick client
software will be launched which will connect to a remote ADSelfServicePlus
server to facilitate the self-service operations.

A security alert can/will be triggered when “an unauthenticated attacker
having physical access to the host issues a self-signed SSL certificate to
the client”. Or, “a (default) self-signed SSL certificate is configured on
ADSelfService Plus server”.

“View Certificate” option from the security alert will allow an attacker
with physical access or a remote attacker with RDP access, to export a
displayed certificate to a file. This will further cascade to the standard
dialog/wizard which will open file explorer as SYSTEM.

By navigating file explorer through “C:\windows\system32\”, a cmd.exe can
be launched as a SYSTEM.

*PoC Video:* https://www.youtube.com/watch?v=slZRXffswnQ

01:00 to 05:30 : Setup the environment
05:30 to 06:34 : Exploitation

Credits:
=======
Bhadresh Patel

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Regards,
-Bhadresh