Vulnerabilities > CVE-2020-1472 - Use of Insufficiently Random Values vulnerability in multiple products
Summary
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.
Vulnerable Configurations
Common Weakness Enumeration (CWE)
Common Attack Pattern Enumeration and Classification (CAPEC)
- Brute Force In this attack, some asset (information, functionality, identity, etc.) is protected by a finite secret value. The attacker attempts to gain access to this asset by using trial-and-error to exhaustively explore all the possible secret values in the hope of finding the secret (or a value that is functionally equivalent) that will unlock the asset. Examples of secrets can include, but are not limited to, passwords, encryption keys, database lookup keys, and initial values to one-way functions. The key factor in this attack is the attackers' ability to explore the possible secret space rapidly. This, in turn, is a function of the size of the secret space and the computational power the attacker is able to bring to bear on the problem. If the attacker has modest resources and the secret space is large, the challenge facing the attacker is intractable. While the defender cannot control the resources available to an attacker, they can control the size of the secret space. Creating a large secret space involves selecting one's secret from as large a field of equally likely alternative secrets as possible and ensuring that an attacker is unable to reduce the size of this field using available clues or cryptanalysis. Doing this is more difficult than it sounds since elimination of patterns (which, in turn, would provide an attacker clues that would help them reduce the space of potential secrets) is difficult to do using deterministic machines, such as computers. Assuming a finite secret space, a brute force attack will eventually succeed. The defender must rely on making sure that the time and resources necessary to do so will exceed the value of the information. For example, a secret space that will likely take hundreds of years to explore is likely safe from raw-brute force attacks.
- Signature Spoofing by Key Recreation An attacker obtains an authoritative or reputable signer's private signature key by exploiting a cryptographic weakness in the signature algorithm or pseudorandom number generation and then uses this key to forge signatures from the original signer to mislead a victim into performing actions that benefit the attacker.
- Session Credential Falsification through Prediction This attack targets predictable session ID in order to gain privileges. The attacker can predict the session ID used during a transaction to perform spoofing and session hijacking.
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References
- https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2020-1472
- http://packetstormsecurity.com/files/159190/Zerologon-Proof-Of-Concept.html
- https://www.kb.cert.org/vuls/id/490028
- http://www.openwall.com/lists/oss-security/2020/09/17/2
- https://usn.ubuntu.com/4510-1/
- https://www.synology.com/security/advisory/Synology_SA_20_21
- https://usn.ubuntu.com/4510-2/
- http://lists.opensuse.org/opensuse-security-announce/2020-09/msg00080.html
- http://lists.opensuse.org/opensuse-security-announce/2020-09/msg00086.html
- https://usn.ubuntu.com/4559-1/
- http://packetstormsecurity.com/files/160127/Zerologon-Netlogon-Privilege-Escalation.html
- https://lists.debian.org/debian-lts-announce/2020/11/msg00041.html
- https://security.gentoo.org/glsa/202012-24
- https://www.oracle.com/security-alerts/cpuApr2021.html
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/H4OTFBL6YDVFH2TBJFJIE4FMHPJEEJK3/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/TAPQQZZAT4TG3XVRTAFV2Y3S7OAHFBUP/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/ST6X3A2XXYMGD4INR26DQ4FP4QSM753B/