CVE-2020-1472
Published: 17 August 2020
Summary
CVE-2020-1472 is a medium-severity an unspecified weakness vulnerability in Canonical Ubuntu Linux. Its CVSS base score is 5.5 (Medium).
Operationally, ranked in the top 0.1% of CVEs by exploit likelihood; CISA has added it to the Known Exploited Vulnerabilities catalog; a public proof-of-concept is referenced.
The strongest mitigations our analysis identified are NIST 800-53 AC-3 (Access Enforcement) and SC-8 (Transmission Confidentiality and Integrity).
Deeper analysis
An elevation of privilege vulnerability exists in the Netlogon Remote Protocol (MS-NRPC) implementation on domain controllers. It allows an attacker to establish a vulnerable Netlogon secure channel connection, after which a specially crafted application can be executed on a device reachable over the network. The flaw affects Windows domain controllers that accept MS-NRPC connections.
An unauthenticated attacker who can reach a domain controller over the network can exploit the issue to obtain domain administrator privileges. Successful exploitation grants full control over Active Directory, enabling arbitrary code execution and lateral movement within the domain.
Microsoft is addressing the vulnerability through a phased, two-part update rollout that changes how Netlogon handles secure channel connections. Guidance for managing the required configuration changes is provided in the article “How to manage the changes in Netlogon secure channel connections associated with CVE-2020-1472,” with a second phase of updates scheduled for Q1 2021. Public proof-of-concept code for the issue, also known as Zerologon, has been released.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2020-12346
Vulnerability details
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…
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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.
- CWE(s)
- KEV Date Added
- 03 November 2021
Related Threats
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Affected Assets
Mitigating Controls
Mitigating Controls (NIST 800-53 r5) AI
Enforces access restrictions on Netlogon secure channel connections so an unauthenticated attacker cannot obtain domain-admin privileges via the MS-NRPC flaw.
Requires cryptographic integrity protection for Netlogon traffic, directly blocking the unauthenticated channel manipulation used by Zerologon.
Mandates timely application of the Microsoft updates that change Netlogon secure-channel handling and close the elevation-of-privilege vector.