Threat actors are actively exploiting Zerologon flaw, Microsoft warns
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 article519 words · extracted from securityaffairs.com · click to collapse
Microsoft researchers are warning that threat actors are continuing to actively exploit the ZeroLogon vulnerability in attacks in the wild.
Microsoft is warning that threat actors are actively exploiting the ZeroLogon vulnerability in the Netlogon Remote Protocol.
The CVE-2020-1472 flaw is an elevation of privilege that resides in the Netlogon. The Netlogon service is an Authentication Mechanism used in the Windows Client Authentication Architecture which verifies logon requests, and it registers, authenticates, and locates Domain Controllers.
An attacker could exploit the vulnerability to impersonate any computer, including the domain controller itself, and execute remote procedure calls on their behalf.
An attacker could also exploit the flaw to disable security features in the Netlogon authentication process and change a computer’s password on the domain controller’s Active Directory.
“Microsoft has received a small number of reports from customers and others about continued activity exploiting a vulnerability affecting the Netlogon protocol (CVE-2020-1472) which was previously addressed in security updates starting on August 11, 2020.” reads a post published by MSRC VP of Engineering Aanchal Gupta. “If the original guidance is not applied, the vulnerability could allow an attacker to spoof a domain controller account that could be used to steal domain credentials and take over the domain.”
Microsoft strongly encourages administrators of enterprise Windows Servers to install the August 2020 Patch Tuesday as soon as possible to protect their systems from Zerologon attack that exploits the CVE-2020-1472.
Reminder to all our Windows customers to deploy at least the August 2020 update or later and follow the original, published guidance to fully resolve the vulnerability, CVE-2020-1472. For further information, see our blog post: https://t.co/br77bEP0mu
— Security Response (@msftsecresponse) October 29, 2020
Because the initial documentation regarding Zerologon patching process was not clear enough, Microsoft provided the following updates:
- UPDATE your Domain Controllers with an update released August 11, 2020 or later.
- FIND which devices are making vulnerable connections by monitoring event logs.
- ADDRESS non-compliant devices making vulnerable connections.
- ENABLE enforcement mode to address CVE-2020-1472 in your environment.
At the end of September, Microsoft issued a similar warning. The IT giant published a series of Tweets to warn of attackers that are actively exploiting the Windows Server Zerologon in attacks in the wild. The IT giant urged Windows administrators to install the released security updates as soon as possible.
In early October, Microsoft spotted a series of Zerologon attacks allegedly launched by the Russian cybercrime group tracked as TA505, CHIMBORAZO and Evil Corp.
Microsoft experts spotted the Zerologon attacks involving fake software updates, the researchers noticed that the malicious code connected to command and control (C&C) infrastructure known to be associated with TA505.
In the same period, Microsoft published a post and a series of tweets to warn of cyber attacks exploiting the Zerologon vulnerability carried out by the Iran-linked APT group known as MuddyWater, aka Mercury.
On September 18, The Department of Homeland Security’s CISA issued an emergency directive to order government agencies to address the Zerologon vulnerability (CVE-2020-1472) by September 21.
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(SecurityAffairs – hacking, Windows)
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