Zabbix Agent 6.2.7 Insecure Permissions / Privilege Escalation Vulnerabilities

# Exploit Title: Zabbix agents - Insecure Permissions on non-default installation directory location
# Discovery by: mmg
# Discovery Date: 2023-01-23
# Vendor Homepage: https://www.zabbix.com/download_agents
# Software Link Zabbix agent : https://cdn.zabbix.com/zabbix/binaries/stable/6.2/6.2.7/zabbix_agent-6.2.7-windows-amd64-openssl.msi
# Software Link Zabbix agent 2 : https://cdn.zabbix.com/zabbix/binaries/stable/6.2/6.2.7/zabbix_agent2-6.2.7-windows-amd64-openssl.msi
# Tested Version: Zabbix agent and Zabbix agent 2 (v6.2.6, v6.2.7 and older versions)
# Vulnerability Type: Local Privilege Escalation
# Tested on OS: Windows 10 Pro Version 22H2 (OS Build 19045.2486) x64 version
# CVSSv3 Vectors : https://www.first.org/cvss/calculator/3.0#CVSS:3.0/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
# CVE N/A


# Step to discover:

Go to Start and type powershell.
Enter the following command and press Enter:
Get-WmiObject win32_service | ?{ $_.Name -like '*zabbix*' -and $_.Pathname -notlike "*C:\Program Files*"}| select Name,PathName

# Example of a vulnerable installation

Name           PathName
----           --------
Zabbix Agent   "C:\Software\Zabbix Agent\zabbix_agentd.exe" --config "C:\Software\Zabbix Agent\zabbix_agentd.conf"
Zabbix Agent 2 "D:\software\Zabbix Agent 2\zabbix_agent2.exe" -c "D:\software\Zabbix Agent 2\zabbix_agent2.conf" -f=false

# Exploit:

A vulnerability was found in Zabbix Agents on non-default installation directory location. 
The Zabbix Agent executables have incorrect permissions, allowing a local unprivileged user to replace it
with a malicious file that will be executed with "LocalSystem" privileges which will result in complete
compromise of Confidentiality, Integrity and Availability.


# Timeline
Jan 23, 2023 - Reported to Zabbix
Feb 1, 2023  - Zabbix does not consider this a vulnerability
Feb 6, 2023  - Requested official approval to disclose it
Feb 8, 2023  - Zabbix agrees with public disclosure
Feb 13, 2023 - Public disclosure