CVE-2019-1415

An elevation of privilege vulnerability exists in Windows Installer because of the way Windows Installer handles certain filesystem operations.To exploit the vulnerability, an attacker would require unprivileged execution on the victim system, aka ‘Windows Installer Elevation of Privilege Vulnerability’.

Recent assessments:

bwatters-r7 at August 24, 2021 7:21pm UTC reported:

There exists a race condition bug in the Windows Installer. Specifically, the Windows installer maintains a rollback script of tasks to be performed in the event that an installation fails. If an installation fails, that rollback script will be run as system. By overwriting that script and placing an instruction to overwrite a specific DLL within that script, an attacker can overwrite a trusted DLL. One bright spot is that the default policy for Windows server prevents non-admins from performing installations, blocking this path for elevation.
In the original write-up by SandboxEscaper, the exploit required GUI interaction, but later PoCs released negated the requirement for clicking on pop-up windows.
Microsoft as attempted to patch this exploit on several occasions, but several patches proved to be incomplete, failing to account for file junctions or other bypass techniques. CVEs issued to bypasses include:
CVE-2021-1727
CVE-2020-16902
CVE-2020-0814
CVE-2020-1302
Links:
<https://www.exploit-db.com/exploits/46916&gt;
<https://ssd-disclosure.com/ssd-advisory-windows-installer-elevation-of-privileges-vulnerability/&gt;
<https://halove23.blogspot.com/2020/12/oh-so-you-have-antivirus-nameevery-bug.html&gt;
<https://github.com/klinix5/CVE-2021-1727&gt;

Assessed Attacker Value: 4
Assessed Attacker Value: 4Assessed Attacker Value: 4