[Summary]
The Pronestor service "PNHM" (aka Health Monitoring or HealthMonitor)
before 8.1.12.0 has "BUILTIN\Users:(I)(F)" permissions for
the "%PROGRAMFILES(X86)%\proNestor\Outlook add-in for Pronestor\PronestorHealthMonitor.exe" file,
which allows local users to gain privileges via a Trojan horse PronestorHealthMonitor.exe file.
During the installation of Pronestors Outlook-Add-In (version 8.1.11.0
and older) the installer creates a service named PNHM (Pronester
Health Monitoring) with weak file permission running as SYSTEM.
The vulnerability allows all "Authenticated Users" to potentially
execute arbitrary code as SYSTEM on the local system.
[Additional Information]
Tested on Windows 7.
Version: Outlook Add-In 8.1.11.0 and older
Also tested on version 5.1.6.0 with same result.
Discovered: 06-nov-2018
Reported: 07-nov-2018
Vendor: https://www.pronestor.com/
Vendor confirmed: True
Fixed: Version 8.1.12.0
Attack Type: Local Privilege Escalation
Vulnerability due to: Insecure Permissions
Discoverer: PovlTekstTV
CVE: 2018-19113
Original link: https://gist.github.com/povlteksttv/8f990e11576e1e90e8fb61acf8646d28
[Proof]
C:\Users\povltekst>sc qc PNHM
SERVICE_NAME: PNHM
TYPE : 10 WIN32_OWN_PROCESS
START_TYPE : 2 AUTO_START
ERROR_CONTROL : 1 NORMAL
BINARY_PATH_NAME : "C:\Program Files (x86)\proNestor\Outlook add-in for Pronestor\PronestorHealthMonitor.exe"
LOAD_ORDER_GROUP :
TAG : 0
DISPLAY_NAME : Pronestor HealthMonitor
DEPENDENCIES :
SERVICE_START_NAME : LocalSystem
C:\Users\povltekst>icacls 'C:\Program Files (x86)\proNestor\Outlook add-in for Pronestor\PronestorHealthMonitor.exe'
C:\Program Files (x86)\proNestor\Outlook add-in for Pronestor\PronestorHealthMonitor.exe
BUILTIN\Users:(I)(F)
NT AUTHORITY\SYSTEM:(I)(F)
BUILTIN\Administrators:(I)(F)
Notice: "BUILIN\Users:(I)(F)". (F) = Full access!
This means that an authenticated user can change the file
[Attack Vectors]
Replace the file "PronestorHealthMonitor.exe" with a malicious file
also called "PronesterHealthMonitor.exe". Next time the service (PNHM)
starts, the malicious file will get executed as SYSTEM. The service
starts on every reboot.
[Affected Component]
PronestorHealthMonitor.exe
This exe will be executed on every reboot by a service named PNHM running as SYSTEM.
