CVE-2022-41091Microsoft Windows Mark of the Web (MOTW) Security Feature Bypass Vulnerability
CVE-2022-41091 is a incorrect authorization in Microsoft Windows, rated medium (5.4 on CVSS 3.1).
Why this priority: Exploited in the wild: listed in CISA's KEV catalog.
Published · Updated · NVD status: Analyzed
What it is
A permission check exists but gets the answer wrong for some callers.
How it is reached
An attacker can exploit it over the network, without an account, but someone has to act first, such as opening a file or following a link.
What an attacker gains
The direct impact is limited: partial access to data or a partial outage. In practice, this kind of flaw lets an attacker reach data or actions their role should not allow.
Is it being exploited?
CISA added it to the Known Exploited Vulnerabilities catalog on 2022-11-08: it is being exploited in the wild. CISA links it to ransomware campaigns. EPSS estimates a 2.3% chance of exploitation activity in the next 30 days, higher than 83% of scored CVEs.
What to do
- Treat it as urgent: it is on CISA's KEV list. CISA's deadline for US federal agencies: 2022-12-09.
- Apply the update for your edition of Microsoft Windows. Fixed builds: Windows 10 Version 1507: 10.0.10240.19567; Windows 10 Version 1607: 10.0.14393.5501; Windows 10 Version 1809: 10.0.17763.3650; Windows 10 Version 20H2: 10.0.19042.2251; Windows 10 Version 21H1: 10.0.19043.2251; Windows 10 Version 21H2: 10.0.19044.2251; and 8 more on this page. The patch notes are linked below.
- Until it is patched, keep it off the internet or behind a VPN, allowlist or authenticating proxy.
- Warn the people who use it, and filter files and links on the way in.
- Check exposed instances for signs of compromise, not only for the version.
Description from NVD
Windows Mark of the Web Security Feature Bypass Vulnerability
What this means for your architecture.
A CVE names a product. Whether it matters depends on where that product sits in your systems: what reaches it, which trust boundary it guards and what it can reach once compromised. Veriom maps your components, their relationships and your trust boundaries from your code, cloud and delivery evidence, so you can see where a component like this sits. The radar itself does not look at your systems.
Components it touches
- Operating systems on servers, workstations or devices. Everything on the host inherits the flaw.
- Permission checks in APIs and admin surfaces. The flaw sits between one role or tenant and another.
- Multi-tenant services. The flaw sits between one role or tenant and another.
Trust boundaries in play
- Internet-facing entry points. No account is needed. Any instance reachable from outside your perimeter, through a load balancer, gateway, VPN or exposed admin port, is in scope.
- People who open files and links. Mail, chat and browsers are the delivery path.
- Between one role or tenant and another. An attacker who crosses it can reach data or actions their role should not allow.
Questions to answer about your own systems
- Where does Microsoft Windows run in your systems, and at which version?
- Which of those instances can be reached from the internet or partner networks?
- What can it reach once compromised: which data stores, secrets and services?
Sources
- CVE records and CVSS scores from the NVD CVE API. This product uses the NVD API but is not endorsed or certified by the NVD.
- Exploitation status from CISA’s Known Exploited Vulnerabilities catalog.
- Exploit likelihood from FIRST’s Exploit Prediction Scoring System (EPSS), refreshed daily.
- Explanations are written by Veriom from fixed templates over each record’s data, not by a person reviewing each CVE. Descriptions are quoted from the records as published.