KB4570333: Windows Server Security Update (September 2020)
Microsoft Edge and Internet Explorer contain a memory corruption vulnerability that allows attackers to execute code in the context of the current user.
A remote attacker, without authentication, can achieve full data confidentiality loss, partial data tampering. CISA has confirmed use of this vulnerability in known ransomware campaigns — treat as high priority for remediation. Federal agencies are required to remediate by 2022-05-03 under CISA BOD 22-01.
This is a Out-of-bounds Write (CWE-787) vulnerability in Microsoft Edge and Internet Explorer. <p>A remote code execution vulnerability exists in the way that Microsoft browsers access objects in memory. The vulnerability could corrupt memory in a way that could allow an attacker to execute arbitrary code in the context of the current user. An attacker who successfully exploited the vulnerability could gain the same user rights as the current user. If the current user is logged on with administrative user rights, the attacker could take control of an affected system. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights.</p> <p>An attacker could host a specially crafted website that is designed to exploit the vulnerability through Microsoft browsers, and then convince a user to view the website. The attacker could also take advantage of compromised websites, or websites that accept or host user-provided content or advertisements, by adding specially crafted content that could exploit the vulnerability. In all cases, however, an attacker would have no way to force users to view the attacker-controlled content. Instead, an attacker would have to convince users to take action, typically via an enticement in email or instant message, or by getting them to open an email attachment.</p> <p>The security update addresses the vulnerability by modifying how Microsoft browsers handle objects in memory.</p> Exploitation requires remote network access, higher attack complexity, no authentication required, and user interaction required.
📧
Phishing link
🖼
Malicious file
🔓
Server compromised
Probably yes if any of these apply:
CISA confirms this CVE has been used in known ransomware campaigns. Added to the KEV catalog on 2021-11-03; federal agencies required to remediate by 2022-05-03.
Manual download
For air-gapped servers or out-of-band deployment. Microsoft Update Catalog returns every OS-version variant of this update.
↗ Microsoft Update CatalogKB4570333Manual remediation steps
Apply the Microsoft Security Update
Microsoft has released an official security update that fixes this vulnerability.
Required KB Updates
Supersedes: KB4565349, KB4565351, KB4566782, KB4571687, KB4571692, KB4571694, KB4571703, KB4571709, KB4571729, KB4571730, KB4571736, KB4571741
Affected Products
Installation Methods
Windows Update (recommended)
Microsoft Update Catalog (manual download)
.msu installer with administrator privilegesWSUS / SCCM / Intune
Approve KB4570333 for the affected products in your update management console.
Microsoft Download Center Links
Verification
Confirm the update is installed:
Get-HotFix | Where-Object { $_.HotFixID -in @('KB4570333','KB4571756','KB4574727','KB4577010','KB4577015','KB4577032','KB4577038','KB4577041','KB4577049','KB4577051','KB4577064','KB4577066') }
References
Discovery Credit
HAO LI of VenusTech ADLab
No tested PowerShell script for this entry yet. We’re prioritising automation based on user demand.