Vulnerability identifier: #VU21685

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-2019-1338

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 NTLMv2 exchange.

The vulnerability exists due to insufficient integrity check for NTLMv2 packets, when the client is also sending LMv2 responses. A remote attacker with ability to modify NTLM traffic exchange can bypass the NTLMv2 protection and gain the ability to downgrade NTLM security features.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

Windows: 7

Windows Server: 2008 - 2008 R2

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External links
http://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2019-1338

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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.