Zero-day vulnerability in Zoho ManageEngine ADSelfService Plus

Improper access control
CVE-2021-40539

Vulnerability details

Advisory: SB2021090902 - Remote code execution in Zoho ADSelfService Plus

Vulnerable component: Zoho ManageEngine ADSelfService Plus

CVE-ID: CVE-2021-40539

CVSSv3 score: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H/E:H/RL:O/RC:C

CWE-ID: CWE-284 - Improper Access Control

Description:

The vulnerability allows a remote attacker to compromise the affected system.

The vulnerability exists due to improper access restrictions to the "/RestAPI/LogonCustomization" and "/RestAPI/Connection" REST API endpoints. A remote non-authenticated attacker can send specially HTTP requests to the aforementioned REST API endpoints and execute arbitrary code on the system.

Note, the vulnerability is being actively exploited in the wild.

External links:

https://www.manageengine.com/products/self-service-password/kb/how-to-fix-authentication-bypass-vulnerability-in-REST-API.html

About zero-day vulnerabilities

Zero-day vulnerability is an undisclosed vulnerability in software that hackers can exploit to compromise computer programs, gain unauthorized access to sensitive data, penetrate networks, etc. We consider vulnerability a zero-day when there is no solution provided from software vendor and the vulnerability is being actively exploited by malicious actors.

Zero-day candidate is a potential zero-day vulnerability in software which might have been used in targeted attacks, however there is no evidence to support this suggestion.