CVE-2020-1472 — samba
MEDIUMCVE-2020-1472 is a medium-severity (CVSS 5.5) vulnerability. It is in CISA's Known Exploited Vulnerabilities catalog (added 2021-11-03) and has been used in ransomware campaigns — treat it as actively exploited and patch now. A fix is available — see the affected versions and patch details below.
Exploitation Status
Actively exploited in the wild
- Confirmed by CISA's Known Exploited Vulnerabilities catalog on 2021-11-03 — including use in ransomware campaigns. Federal agencies were required to remediate by 2022-05-03.
- CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
- A successful exploit gives an attacker total control of the affected component, not partial access.
Exploitation and automatability from CISA (KEV catalog and SSVC triage) for CVE-2020-1472.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
CVE-2020-1472 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.
Where this sits among everything scored
Of 396,257 CVEs with a current EPSS score, this one falls in the ≥ 90% band (highlighted). Counts from FIRST.org, log-scaled.
Description
An elevation of privilege vulnerability exists when an attacker establishes a vulnerable Netlogon secure channel connection to a domain controller, using the Netlogon Remote Protocol (MS-NRPC). An attacker who successfully exploited the vulnerability could run a specially crafted application on a device on the network. To exploit the vulnerability, an unauthenticated attacker would be required to use MS-NRPC to connect to a domain controller to obtain domain administrator access. Microsoft is addressing the vulnerability in a phased two-part rollout. These updates address the vulnerability by modifying how Netlogon handles the usage of Netlogon secure channels. For guidelines on how to manage the changes required for this vulnerability and more information on the phased rollout, see How to manage the changes in Netlogon secure channel connections associated with CVE-2020-1472 (updated September 28, 2020). When the second phase of Windows updates become available in Q1 2021, customers will be notified via a revision to this security vulnerability. If you wish to be notified when these updates are released, we recommend that you register for the security notifications mailer to be alerted of content changes to this advisory. See Microsoft Technical Security Notifications.
Affected Products
ubuntu linuxcanonicaldebian linuxdebianfedorafedoraprojectwindows server 20h2microsoftwindows server 1903microsoftwindows server 1909microsoftResearch use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.
ZeroLogon - Netlogon Elevation of Privilege
by West Shepherd · Nov 18, 2020
Detection & mitigation playbook
VulnerabilityDetect
Identify every host running the affected component and compare the installed build against the fixed version below — for source-built or distro-packaged software the version string, not a lockfile, is the source of truth (`dpkg -l`, `rpm -q`, or the binary's own `--version`).
Fix
Upgrade the affected component to the fixed release for CVE-2020-1472, or apply your distribution's backported patch — distro builds are often patched at an older version number, so check your vendor's advisory rather than the upstream version alone.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
Fixing This On Your OS
If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.
As per upstream samba domain controllers (AD and NT4-like) can be impacted by the ZeroLogon CVE-2020-1472. Samba packages shipped with Red Hat Gluster Storage 3, Red Hat Enterprise Linux 7 and 8 are not vulnerable by default, since they have "server schannel" enabled by default in its configuration file.
This flaw can be mitigated by using "server schannel = yes" in the smb.conf configuration file.Source: Red Hat security advisory for CVE-2020-1472 (CC BY 4.0)
| Product | Fixed in | Advisory |
|---|---|---|
| Red Hat Enterprise Linux 7 | samba-0:4.10.16-9.el7_9 | RHSA-2020:5439 |
| Red Hat Enterprise Linux 8 | openchange-0:2.3-27.el8 | RHSA-2021:1647 |
| Red Hat Gluster Storage 3.5 for RHEL 7 | samba-0:4.11.6-112.el7rhgs | RHSA-2021:3723 |
| Red Hat Gluster Storage 3.5 for RHEL 8 | samba-0:4.13.7-101.el8rhgs | RHBA-2021:1503 |
Frequently Asked Questions
Is CVE-2020-1472 in your dependencies?
Find it across , including transitive dependencies.