CVE-2020-1350 — Windows DNS Server Remote Code Execution Vulnerability

Executive Summary

A remote code execution vulnerability exists in Windows Domain Name System servers when they fail to properly handle requests. An attacker who successfully exploited the vulnerability could run arbitrary code in the context of the Local System Account. Windows servers that are configured as DNS servers are at risk from this vulnerability. To exploit the vulnerability, an unauthenticated attacker could send malicious requests to a Windows DNS server. The update addresses the vulnerability by modifying how Windows DNS servers handle requests.

Overview

10

CVSS CRITICAL

Critical

MS Severity

Not Exploited

MS Exploit Status

More Likely

MS Exploit Likelihood

Category Remote Code Execution

Released Jul 14 2020

Last Updated Jul 14 2020

Publicly Disclosed No

CISA KEV Listed (added 2021-11-03)

Known Exploits None Known

EPSS Score 0.91353 — 0.99803 percentile

NVD CVSS 10 CRITICAL — matches MSRC

CVSS Vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H/E:P/RL:O/RC:C

ATTACK VECTOR

Network

ATTACK COMPLEXITY

Low

PRIVILEGES REQUIRED

None

USER INTERACTION

None

SCOPE

Changed

CONFIDENTIALITY

High

INTEGRITY

High

AVAILABILITY

High

EXPLOIT CODE MATURITY

Proof-of-Concept

REMEDIATION LEVEL

Official Fix

REPORT CONFIDENCE

Confirmed

Temporal Score: 9.0

EPSS Score

0.91353

probability of exploitation in the next 30 days

0.99803 percentile - updated 2026-08-14

View on FIRST.org

Affected Products

7 affected products

Product	KB Article	Severity	Impact	Restart Required
Windows Server 2008 for 32-bit Systems Service Pack 2 4565536 (Monthly Rollup) 4565529 (Security Only) Critical Remote Code Execution 4561670 Base: 10.0 Temporal: 9.0 Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H/E:P/RL:O/RC:C Yes 4565536 4565529 Windows Server 2008 for 32-bit Systems Service Pack 2 (Server Core installation) 4565536 (Monthly Rollup) 4565529 (Security Only) Critical Remote Code Execution 4561670 Base: 10.0 Temporal: 9.0 Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H/E:P/RL:O/RC:C Yes 4565536 4565529 Windows Server 2008 for x64-based Systems Service Pack 2 4565536 (Monthly Rollup) 4565529 (Security Only) Critical Remote Code Execution 4561670 Base: 10.0 Temporal: 9.0 Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H/E:P/RL:O/RC:C Yes 4565536 4565529 Windows Server 2008 for x64-based Systems Service Pack 2 (Server Core installation) 4565536 (Monthly Rollup) 4565529 (Security Only) Critical Remote Code Execution 4561670 Base: 10.0 Temporal: 9.0 Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H/E:P/RL:O/RC:C Yes 4565536 4565529 Windows Server 2008 R2 for x64-based Systems Service Pack 1 4565524 (Monthly Rollup) 4565539 (Security Only) Critical Remote Code Execution 4561643 Base: 10.0 Temporal: 9.0 Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H/E:P/RL:O/RC:C Yes 4565524 4565539 Windows Server 2008 R2 for x64-based Systems Service Pack 1 (Server Core installation) 4565524 (Monthly Rollup) 4565539 (Security Only) Critical Remote Code Execution 4561643 Base: 10.0 Temporal: 9.0 Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H/E:P/RL:O/RC:C Yes 4565524 4565539 Windows Server 2012 4565537 (Monthly Rollup) 4565535 (Security Only) Critical Remote Code Execution 4561612 Base: 10.0 Temporal: 9.0 Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H/E:P/RL:O/RC:C Yes 4565537 4565535 Windows Server 2012 (Server Core installation) 4565537 (Monthly Rollup) 4565535 (Security Only) Critical Remote Code Execution 4561612 Base: 10.0 Temporal: 9.0 Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H/E:P/RL:O/RC:C Yes 4565537 4565535 Windows Server 2012 R2 4565541 (Monthly Rollup) 4565540 (Security Only) Critical Remote Code Execution 4561666 Base: 10.0 Temporal: 9.0 Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H/E:P/RL:O/RC:C Yes 4565541 4565540 Windows Server 2012 R2 (Server Core installation) 4565541 (Monthly Rollup) 4565540 (Security Only) Critical Remote Code Execution 4561666 Base: 10.0 Temporal: 9.0 Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H/E:P/RL:O/RC:C Yes 4565541 4565540 Windows Server 2016	`4565511 (Security Update)`	Critical	Remote Code Execution	Yes
Windows Server 2016 (Server Core installation)	`4565511 (Security Update)`	Critical	Remote Code Execution	Yes
Windows Server 2019	`4558998 (Security Update)`	Critical	Remote Code Execution	Yes
Windows Server 2019 (Server Core installation)	`4558998 (Security Update)`	Critical	Remote Code Execution	Yes
Windows Server, version 1903 (Server Core installation)	`4565483 (Security Update)`	Critical	Remote Code Execution	Yes
Windows Server, version 1909 (Server Core installation)	`4565483 (Security Update)`	Critical	Remote Code Execution	Yes
Windows Server, version 2004 (Server Core installation)	`4565503 (Security Update)`	Critical	Remote Code Execution	Yes

Patches

4 patches

Article	Type	Restart
`4565511`	Security Update	Yes
`4558998`	Security Update	Yes
`4565483`	Security Update	Yes
`4565503`	Security Update	Yes

Exploits & PoC

15 public PoCs

Unverified third-party code

Public proof-of-concept repositories aggregated from PoC-in-GitHub. They are not reviewed and may be incomplete, non-functional, or malicious — inspect the code before running anything.

Repository	Stars	Published	Description
ZephrFish/CVE-2020-1350_HoneyPoC	280	2020-07-14	HoneyPoC: Proof-of-Concept (PoC) script to exploit SIGRed (CVE-2020-1350). Achieves Domain Admin on Domain Controllers running Windows Server 2000 up to Windows Server 2019.
maxpl0it/CVE-2020-1350-DoS	238	2020-07-15	A denial-of-service proof-of-concept for CVE-2020-1350
psc4re/NSE-scripts	162	2020-03-11	NSE scripts to detect CVE-2020-1350 SIGRED and CVE-2020-0796 SMBGHOST, CVE-2021-21972, proxyshell, CVE-2021-34473
captainGeech42/CVE-2020-1350	18	2020-07-16	Denial of Service PoC for CVE-2020-1350 (SIGRed)
T13nn3s/CVE-2020-1350	15	2020-07-15	This Powershell Script is checking if your server is vulnerable for the CVE-2020-1350 Remote Code Execution flaw in the Windows DNS Service
connormcgarr/CVE-2020-1350	11	2020-07-17	CVE-2020-1350 Proof-of-Concept
corelight/SIGRed	9	2020-07-15	Detection of attempts to exploit Microsoft Windows DNS server via CVE-2020-1350 (AKA SIGRed)
zoomerxsec/Fake_CVE-2020-1350	7	2020-07-14	Fake exploit tool, designed to rickroll users attempting to actually exploit.
mr-r3b00t/CVE-2020-1350	4	2020-07-14
graph-inc/CVE-2020-1350	2	2020-07-18	Scanner and Mitigator for CVE 2020-1350
simeononsecurity/CVE-2020-1350-Fix	2	2020-07-26	A registry-based workaround can be used to help protect an affected Windows server, and it can be implemented without requiring an administrator to restart the server. Because of the volatility of thi
jmaddington/dRMM-CVE-2020-1350-response	0	2020-07-15	Windows registry mitigation response to CVE-2020-1350
CVEmaster/CVE-2020-1350	0	2020-07-19	DNS Vulnerability - CVE-2020-1350
gdwnet/cve-2020-1350	0	2020-07-22	A powershell script to deploy the registry mitigation key for CVE-2020-1350
sty886/CVE-2020-1350-SigRed	0	2026-03-07	CVE-2020-1350的PoC

Detection Rules

Detection available

Community detection & vulnerability-scanning rules aggregated from Sigma and Nuclei templates. Validate and tune to your environment before deploying.

Sigma rules 4

DNS RCE CVE-2020-1350 critical Unusual File Modification by dns.exe high Unusual File Deletion by Dns.exe high Unusual Child Process of dns.exe high

Acknowledgments

Sagi Tzadik and Eyal Itkin from Check Point Research

References

MSRC Advisory MITRE NVD