Actively exploited vulnerability

Microsoft Windows: privilege escalation flaw under attack

CVE-2015-1769 · Microsoft Windows Mount Manager Privilege Escalation Vulnerability

Concerns everyone who uses it6.6 medium

What is affected

Microsoft Windows is found on ordinary personal computers and phones, so this is not only a problem for companies. If you use it and have not updated since the fix was released, you are exposed.

A privilege escalation vulnerability exists when the Windows Mount Manager component improperly processes symbolic links.

CISA's description

What an attacker can do

This is a privilege escalation flaw. It lets an attacker turn limited access into full administrator control. Attackers pair it with another flaw or a malicious file: once anything of theirs runs on the device, this bug lets it take over completely.

How it is reached
Needs physical access
Access the attacker needs
A basic user account
Does the victim have to do something?
No, works without the victim doing anything

What to do

  1. Update Microsoft Windows now. Open the update or "About" screen, install whatever is offered and restart the app or device, because the fix is not active until you do.
  2. Turn on automatic updates so the next fix arrives without you having to look for it.
  3. If your device is too old to receive this update, stop using the affected app for anything sensitive and plan a replacement.

Apply updates per vendor instructions.

Action required by CISA for US federal agencies

How urgent is it

CISA added this vulnerability to its Known Exploited Vulnerabilities catalogue on May 25, 2022, which means there is reliable evidence of attacks in the wild. US federal agencies must fix it by June 15, 2022, a deadline that has already passed. That deadline does not bind anyone else, but it shows how seriously the agency rates it.

The EPSS model estimates a 4.1% probability that this flaw will be exploited somewhere in the next 30 days. That is higher than 90% of all scored vulnerabilities.

Its CVSS severity score is 6.6 out of 10 (medium), as recorded in the US National Vulnerability Database.

Technical description

Mount Manager in Microsoft Windows Vista SP2, Windows Server 2008 SP2 and R2 SP1, Windows 7 SP1, Windows 8, Windows 8.1, Windows Server 2012 Gold and R2, Windows RT Gold and 8.1, and Windows 10 mishandles symlinks, which allows physically proximate attackers to execute arbitrary code by connecting a crafted USB device, aka "Mount Manager Elevation of Privilege Vulnerability."

NIST National Vulnerability Database
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