Vulnerability identifier: #VU21684

Vulnerability risk: Medium

CVSSv3.1: 5.3 [CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N/E:U/RL:O/RC:C]

CVE-ID: CVE-2019-1166

CWE-ID: CWE-300

Exploitation vector: Local network

Exploit availability: No

Vulnerable software:
Windows
Operating systems & Components / Operating system
Windows Server
Operating systems & Components / Operating system

Vendor: Microsoft

Description

The vulnerability allows a remote attacker to tamper with the NTLM exchange.

The vulnerability exists due to insufficient integrity check for NTLM packets. A remote attacker can modify flags of the NTLM packet without invalidating the signature and bypass the NTLM MIC (Message Integrity Check) protection.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

Windows: 7, 8.1 - 8.1 RT, 10 - 10 1903

Windows Server: 2008 - 2019 1903

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External links
http://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2019-1166

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Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the local network (LAN).

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.