MNDT-2022-0024
Description
HCL BigFix Client for Windows contains a local privilege escalation vulnerability prior to version 10.0.6/9.5.19.
Impact
High - Exploiting the vulnerability will give a local unprivileged attacker SYSTEM level privileges.
Exploitability
Medium - Any authenticated local user can exploit the vulnerability and an exploit is trivial to produce.
CVE Reference
CVE-2021-27766
Common Weakness Enumeration
CWE-379: Creation of Temporary File in Directory with Insecure Permissions
Common Vulnerability Scoring System
Base Score: 7.8 - Vector: AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Technical Details
The installation of the agent uses the Windows Installer framework and an MSI file is cached in c:\windows\installer. An unprivileged user can trigger a repair operation, either by using the Windows Installer API or by running "msiexec.exe /fa c:\windows\installer\[XXXXX].msi".
Running a repair operation will trigger a number of file operations in the %TEMP% folder of the user triggering the repair. Some of these operations will be performed from a SYSTEM context (started via the Windows Installer service), including the execution of temporary files.
Resolution
The issue was fixed in version 10.0.6/9.5.19. Update to this version to address the vulnerability.
Discovery Credits
- Ronnie Salomonsen, Mandiant
Disclosure Timeline
- 28-Sep-2021 - Issue reported to HCL
- 19-Dec-2021 - Issue confirmed by HCL and a fix scheduled for April 21, 2022.
- 21-Apr-2022 - Patched version released by HCL