CISA orders federal agencies to implement Zerologon fix by Monday
Vulnerabilities mentionedAll →
| CVE | Vulnerability | CVSS | EPSS | Flags | Affected | Exposure | Published |
|---|---|---|---|---|---|---|---|
| CVE-2020-1472 | Unauthenticated Privilege Escalation (Zerologon) in Microsoft Netlogon Domain Controllers CVE-2020-1472, widely known as "Zerologon," is an elevation-of-privilege flaw in how the Netlogon secure channel is established over the Netlogon Remote Protocol (MS-NRPC) on Microsoft domain controllers. An unauthenticated attacker with network reachability to a domain controller sends specially crafted Netlogon messages to establish a vulnerable secure channel and then runs a specially crafted application on the network to obtain domain administrator access. Successful exploitation yields domain administrator privileges, effectively full compromise of the Active Directory environment, and the flaw is known to be used in ransomware operations. Any organization running affected Windows Server versions (2008 through 20H2) as domain controllers is exposed, along with environments using Netlogon implementations from Samba and distributions or products from Fedora, openSUSE, Canonical (Ubuntu), Debian, Synology, and Oracle. Exploitation is highly active: a public Zerologon PoC/exploit is available, the flaw is on CISA's Known Exploited Vulnerabilities catalog (added 2021-11-03, with known ransomware use), and EPSS estimates a 99.4% probability of exploitation within 30 days. Do: Apply the vendor updates on all domain controllers and other affected systems immediately, following Microsoft's two-phase Netlogon secure channel guidance (the enforcement phase of the phased rollout began in Q1 2021). Audit Netlogon secure-channel connections and event logs for clients still using vulnerable connections before enabling full enforcement, and install updated packages for Samba and other Netlogon implementations from Fedora, openSUSE, Ubuntu, Debian, Synology, and Oracle. Given known ransomware use, prioritize patching any domain controller reachable from user networks, VPNs, or the internet. | 5.5 | 99% | KEV ransomware PoC |
| massmillions of domain controllers worldwide (essentially every Active Directory domain), with hundreds of thousands of domain controllers/RPC endpoints… |
Full article390 words · extracted from helpnetsecurity.com · click to collapse
If you had any doubts about the criticality of the Zerologon vulnerability (CVE-2020-1472) affecting Windows Server, here is a confirmation: the US Cybersecurity and Infrastructure Security Agency (CISA) has issued on Friday an emergency directive instructing federal agencies to “immediately apply the Windows Server August 2020 security update to all domain controllers” – and to do so by the end of Monday (September 21).
“If affected domain controllers cannot be updated, ensure they are removed from the network,” CISA advised.
To make sure the order has been complied with, the agency asks department-level Chief Information Officers (CIOs) or equivalents to submit completion reports by Wednesday.
About the vulnerability
Security updates fixing CVE-2020-1472, a privilege elevation vulnerability in the Netlogon Remote Protocol (MS-NRPC), were provided by Microsoft in August, and the researchers who discovered the bug revealed more technical information about it last week.
That release was followed by the publication of a slew of PoC exploits.
Zerologon’s severity stems from the fact that it can be leveraged by an unauthenticated attacker with network access to a domain controller to impersonate any domain-joined computer, including a domain controller.
“Among other actions, the attacker can set an empty password for the domain controller’s Active Directory computer account, causing a denial of service, and potentially allowing the attacker to gain domain administrator privileges. The compromise of Active Directory infrastructure is likely a significant and costly impact,” CERT/CC says.
The risk
“CISA has determined that this vulnerability poses an unacceptable risk to the Federal Civilian Executive Branch and requires an immediate and emergency action,” the agency noted in the emergency directive.
“This determination is based on the following: the availability of the exploit code in the wild increasing likelihood of any upatched domain controller being exploited; the widespread presence of the affected domain controllers across the federal enterprise; the high potential for a compromise of agency information systems; the grave impact of a successful compromise; and the continued presence of the vulnerability more than 30 days since the update was released.”
State and local governments should heed this call as well, not to mention organizations in the private sector.
We’re still to hear about the vulnerability being actively exploited in the wild, but it’s just a matter of time until attackers gain the ability to leverage it and start doing it.
Text extracted automatically; images, tables and formatting may be missing. Original: https://www.helpnetsecurity.com/2020/09/21/cisa-orders-federal-agencies-to-implement-zerologon-fix-by-monday/