Hacker Discloses New Unpatched Windows Zero-Day Exploit On Twitter

SandboxEscaper is the same researcher who previously publicly
dropped exploits for two Windows zero-day vulnerabilities, leaving
all Windows users vulnerable to the hackers until Microsoft patched
them.

The newly disclosed
unpatched Windows zero-day vulnerability is an arbitrary file read
issue that could allow a low-privileged user or a malicious program
to read the content of any file on a targeted Windows computer that
otherwise would only be possible via administrator-level
privileges.
^[2]

The zero-day vulnerability resides in “MsiAdvertiseProduct”
function of Windows that’s responsible for generating “an advertise
script or advertises a product to the computer and enables the
installer to write to a script the registry and shortcut
information used to assign or publish a product.”

According to the researcher, due to improper validation, the
affected function can be abused to force installer service into
making a copy of any file as SYSTEM privileges and read its
content, resulting in arbitrary file read vulnerability.

“Even without an enumeration vector, this is still bad news,
because a lot of document software, like office, will actually keep
files in static locations that contain the full path and file names
of recently opened documents..,” the researcher said.

“Thus by reading files like this, you can get filenames of
documents created by other users.. the filesystem is a spiderweb
and references to user-created files can be found everywhere.. so
not having an enumeration bug is not that big of a deal.”

Besides sharing video demonstration of the vulnerability,
SandboxEscaper also posted a link to a Github page
hosting its proof-of-concept (PoC) exploit for the third Windows
zero-day vulnerability, but the researcher’s GitHub account has
since been taken down.
^[3]

This is the third time in the past few months SandboxEscaper has
leaked a Windows zero-day vulnerability.

In October, SandboxEscaper released a PoC exploit for a
privilege escalation^[4]
vulnerability in Microsoft Data Sharing that allowed a low
privileged user to delete critical system files from a targeted
Windows system.

In late August, the researcher exposed details and
PoC exploit^[5] for a local privilege
escalation flaw in Microsoft Windows Task Scheduler occurred due to
errors in the handling of the Advanced Local Procedure Call (ALPC)
service.

Shortly after the PoC released, the then-zero-day vulnerability
was found actively being exploited in the wild, before Microsoft
addressed it in the September 2018
Security Patch^[6] Tuesday
Updates.

^[1]