[BreachExchange] Hacker Discloses New Unpatched Windows Zero-Day Exploit On Twitter

[Destry Winant]

https://thehackernews.com/2018/12/windows-zero-day-exploit.html

A security researcher with Twitter alias SandboxEscaper today released
proof-of-concept (PoC) exploit for a new zero-day vulnerability
affecting Microsoft's Windows operating system.

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.

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.

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 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 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 Tuesday Updates.