Authentication byass in Microsoft Windows RDP

1) Improper Authentication

EUVDB-ID: #VU18684

Risk: Low

CVSSv3.1: 4.7 [CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:L/A:L/E:P/RL:U/RC:C]

CVE-ID: CVE-2019-9510

CWE-ID: CWE-287 - Improper Authentication

Exploit availability: No

Description

The vulnerability allows a remote attacker to bypass authentication process.

The vulnerability exists due to a logical error in implementation of RDP Network Level Authentication (NLA) when authenticating users after interrupted network connection. Remote Desktop server allows users to automatically authenticate in case of network connectivity loss without providing access credentials. An attacker with access a machine that is being used as RDP client can interrupt connection between the client and remote RDP server, then reconnect to the server and gain access to a remote session that belongs to another workstation user.

Mitigation

Cybersecurity Help is currently unaware of any official solution to address this vulnerability.

Vulnerable software versions

Windows Server: 2019 - 2019 1903

Windows: 10 - 10 Gold

External links

http://www.kb.cert.org/vuls/id/576688/

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability. However, proof of concept for this vulnerability is available.