CVE-2019-1040

MEDIUM EXPLOITED IN THE WILD

Microsoft Windows - Privilege Escalation

Title source: llm
STIX 2.1

Exploitation Summary

CVE-2019-1040 has been observed exploited in the wild (reported by VulnCheck KEV, InTheWild.io). EIP tracks 7 public exploits from researchers including fox-it, Ridter, QAX-A-Team.

AI-analyzed exploit summary This repository contains a scanner for CVE-2019-1040, which checks for vulnerability to the MIC Remove attack by sending invalid NTLM authentication packets over SMB. It does not exploit the vulnerability but detects if the target is vulnerable.

Description

A tampering vulnerability exists in Microsoft Windows when a man-in-the-middle attacker is able to successfully bypass the NTLM MIC (Message Integrity Check) protection. An attacker who successfully exploited this vulnerability could gain the ability to downgrade NTLM security features. To exploit this vulnerability, the attacker would need to tamper with the NTLM exchange. The attacker could then modify flags of the NTLM packet without invalidating the signature. The update addresses the vulnerability by hardening NTLM MIC protection on the server-side.

Exploits (7)

nomisec SCANNER 301 stars
by fox-it · infoleak
https://github.com/fox-it/cve-2019-1040-scanner

This repository contains a scanner for CVE-2019-1040, which checks for vulnerability to the MIC Remove attack by sending invalid NTLM authentication packets over SMB. It does not exploit the vulnerability but detects if the target is vulnerable.

Classification
Scanner 100%
Attack Type
Auth Bypass
Complexity
Moderate
Reliability
Reliable
Target: Windows systems with NTLM authentication
Auth required
Prerequisites: Valid credentials or hashes for authentication · SMB access to the target
devstral-2 · analyzed Feb 18, 2026 Full analysis →
nomisec WORKING POC 253 stars
by Ridter · remote-auth
https://github.com/Ridter/CVE-2019-1040

This repository contains a functional exploit for CVE-2019-1040, leveraging the NTLM relay attack via the PrinterBug technique to trigger authentication and relay credentials. It includes modules for SMB and HTTP relay servers, as well as utilities for dumping secrets and restoring operations.

Classification
Working Poc 95%
Attack Type
Auth Bypass
Complexity
Moderate
Reliability
Reliable
Target: Windows systems with NTLM authentication
No auth needed
Prerequisites: Network access to target · SMB/HTTP services exposed · NTLM authentication enabled
devstral-2 · analyzed Feb 18, 2026 Full analysis →
nomisec WORKING POC 72 stars
by QAX-A-Team · remote
https://github.com/QAX-A-Team/dcpwn

This repository contains a functional Python exploit for CVE-2019-1040, leveraging NTLM relay attacks to manipulate LDAP and Kerberos authentication. The script automates the creation of machine accounts and exploits the vulnerability to achieve privilege escalation or lateral movement.

Classification
Working Poc 95%
Attack Type
Auth Bypass
Complexity
Complex
Reliability
Reliable
Target: Microsoft Windows Active Directory (NTLM Relay)
Auth required
Prerequisites: Valid domain credentials or NTLM hash · Network access to target domain controller · Impacket library installed
devstral-2 · analyzed Feb 18, 2026 Full analysis →
nomisec WORKING POC 33 stars
by Ridter · client-side
https://github.com/Ridter/CVE-2019-1040-dcpwn

This repository contains a functional exploit for CVE-2019-1040, which leverages NTLM relay vulnerabilities combined with Kerberos delegation to achieve remote code execution and potential domain admin privileges. The tool, `dcpwn.py`, automates the exploitation process by integrating with Impacket and includes modules for various attack vectors such as SMB, LDAP, and HTTP relay attacks.

Classification
Working Poc 95%
Attack Type
Rce
Complexity
Complex
Reliability
Reliable
Target: Windows Domain Controllers with NTLM relay and Kerberos delegation misconfigurations
Auth required
Prerequisites: Valid domain credentials or hashes · Access to a vulnerable domain controller · NTLM relay attack surface (e.g., SMB, LDAP, HTTP) · Kerberos delegation misconfiguration
devstral-2 · analyzed Feb 18, 2026 Full analysis →
nomisec WORKING POC 20 stars
by lazaars · client-side
https://github.com/lazaars/UltraRealy_with_CVE-2019-1040

This repository contains a functional exploit for CVE-2019-1040, which leverages LLMNR poisoning and NTLM relay attacks to achieve remote code execution (RCE). The tool is an updated version of UltraRelay, incorporating the `--remove-mic` flag to bypass NTLM mitigation by exploiting the MIC (Message Integrity Code) removal vulnerability.

Classification
Working Poc 95%
Attack Type
Rce
Complexity
Moderate
Reliability
Reliable
Target: Windows systems with NTLM authentication (specifically vulnerable to CVE-2019-1040)
No auth needed
Prerequisites: Network access to target systems · LLMNR/NBT-NS enabled on target network · Vulnerable NTLM configuration
devstral-2 · analyzed Feb 18, 2026 Full analysis →
nomisec WORKING POC
by JonyFilc · poc
https://github.com/JonyFilc/PrintSpoofer-ReflectiveDLL

This repository contains a functional exploit for CVE-2019-1040, leveraging the Print Spooler service to achieve local privilege escalation (LPE) via named pipe impersonation. The code includes reflective DLL injection and RPC-based exploitation techniques.

Classification
Working Poc 95%
Attack Type
Lpe
Complexity
Moderate
Reliability
Reliable
Target: Windows Print Spooler Service
No auth needed
Prerequisites: Local access to a vulnerable Windows system · Print Spooler service running
devstral-2 · analyzed Feb 19, 2026 Full analysis →
patchapalooza WORKING POC
by godzeo · poc
https://gitee.com/godzeo/CVE-2019-1040

This repository contains a functional exploit for CVE-2019-1040, which leverages NTLM relay vulnerabilities in Exchange servers to achieve remote code execution and domain admin privileges. The code includes modules for various relay attacks (SMB, LDAP, HTTP, etc.) and integrates with Impacket for authentication and execution.

Classification
Working Poc 95%
Attack Type
Rce
Complexity
Moderate
Reliability
Reliable
Target: Microsoft Exchange Server (versions affected by CVE-2019-1040)
Auth required
Prerequisites: Valid credentials or NTLM hashes for authentication · Network access to the target Exchange server · Attacker-controlled host for relaying NTLM authentication
devstral-2 · analyzed Feb 23, 2026 Full analysis →

Scores

CVSS v3 5.3
EPSS 0.8968
EPSS Percentile 99.6%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:H/A:N

Details

VulnCheck KEV 2020-10-20
InTheWild.io 2020-12-23
Status published
Products (18)
microsoft/windows_10
microsoft/windows_10 1607
microsoft/windows_10 1703
microsoft/windows_10 1709
microsoft/windows_10 1803
microsoft/windows_10 1809
microsoft/windows_10 1903
microsoft/windows_7
microsoft/windows_8.1
microsoft/windows_rt_8.1
... and 8 more
Published Jun 12, 2019
Tracked Since Feb 18, 2026