Vulnerability identifier: #VU6544

Vulnerability risk: Medium

CVSSv3.1: 6.9 [CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H/E:P/RL:O/RC:C]

CVE-ID: CVE-2017-7478

CWE-ID: CWE-20

Exploitation vector: Network

Exploit availability: Yes

Vulnerable software:
OpenVPN
Server applications / Remote access servers, VPN

Vendor: openvpn.net

Description
The vulnerability allows a remote authenticated attacker to cause DoS conditions on the target system.

The weakness exists due to improper user-input validation. A remote attacker can send a specially crafted P_CONTROL packet and cause the OpenVPN server process to stop running due to an ASSERT() exception.

Successful exploitation of the vulnerability results in denial of service.

Mitigation
Update to version 2.3.15, 2.4.2 or later.

Vulnerable software versions

OpenVPN: 2.4.0 - 2.4.1, 2.3.12 - 2.3.14

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External links
http://community.openvpn.net/openvpn/wiki/QuarkslabAndCryptographyEngineerAudits

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Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote authenticated user 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.