Advisory CVE-2020-13771 – Ivanti Unified Endpoint Manager DLL search order hijacking privilege escalation

Software: Ivanti Unified Endpoint Manager Affected Versions: <= 2020.1.1 Vendor page: www.ivanti.com CVE Reference: CVE-2020-13771 Published: 11/11/2020 CVSS 3.1 Score: 8.1 – AV:L/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H Attack Vector: Local Credit: Andrei Constantin Scutariu, Lenk Ratchakrit, Calvin Yau

Summary

Various services running as user ‘NT AUTHORITY\SYSTEM’ rely on Windows’ DLL search order for loading DLL files that are not present on the filesystem. Under certain circumstances, a local attacker would be able to place a malicious DLL file to obtain code execution in the vulnerable service’s context to elevate privileges.

Mitigation

The vendor has released an update partially fixing the issue. 2019.1.4 and 2020.1.1 releases can be installed to remediate some of the instances; the remaining instances remain outstanding. It is advised to review the host configuration and monitor for suspicious activity.

Technical details

Affected services attempt to load DLL libraries which are not found on the filesystem relying on Windows’ DLL search order. A local attacker able to place a purposely crafted library in one of the directories searched, such as one listed in the PATH system environment variable, would gain code execution in the context of the vulnerable service.

Vulnerable instances on version <= 2020.1.1

Service “LANDesk Inventory Server”:

• ldprofileui.dll

Vulnerable instances on version <= 2020.1

Service “LANDesk Inventory Server”:

• wfapi.dll
• DMIAPI32.DLL
• logonsrv.dll
• ldprofileui.dll

Service “LANDesk(R) Console Redirection Service”:

• OOBCredentials.dll

Timeline

15/04/2020: Issue reported to the vendor 16/04/2020: Vendor acknowledged the issues 02/06/2020: CVE number assigned from MITRE 13/07/2020: 90 days notice period for disclosure given to the vendor 11/11/2020: Advisory published by JUMPSEC