FreeBSD update for OpenSSH

1) Consuming excessive CPU resources on the target system

EUVDB-ID: #VU252

Risk: Medium

CVSSv3.1: 7.7 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H/E:P/RL:O/RC:C]

CVE-ID: CVE-2016-6515

CWE-ID: CWE-400 - Resource exhaustion

Exploit availability: Yes

Description

The vulnerability allows a remote attacker to consume excessive CPU resources on the target system.

The vulnerability exists in the crypt(3) function, which accepts passwords longer that 1024 characters in auth_password() function in the auth_passwd.c . A remote unauthenticated attacker can submit a very long string as a password and consume excessive CPU resources.

Successful exploitation of this vulnerability may result in denial of service.

Mitigation

Apply security patch.

Vulnerable software versions

FreeBSD: 10.0 - 11.1

External links

http://www.freebsd.org/security/advisories/FreeBSD-SA-17:06.openssh.asc

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.