Test ID:	1.3.6.1.4.1.25623.1.0.809154
Category:	Denial of Service
Title:	OpenSSH < 7.3 DoS and User Enumeration Vulnerabilities - Linux
Summary:	OpenSSH is prone to denial of service (DoS) and user enumeration; vulnerabilities.
Description:	Summary: OpenSSH is prone to denial of service (DoS) and user enumeration vulnerabilities. Vulnerability Insight: Multiple flaws exist due to: - The auth_password function in 'auth-passwd.c' script does not limit password lengths for password authentication. - The sshd in OpenSSH, when SHA256 or SHA512 are used for user password hashing uses BLOWFISH hashing on a static password when the username does not exist and it takes much longer to calculate SHA256/SHA512 hash than BLOWFISH hash. Vulnerability Impact: Successfully exploiting this issue allows remote attackers to cause a denial of service (crypt CPU consumption) and to enumerate users by leveraging the timing difference between responses when a large password is provided. Affected Software/OS: OpenSSH versions before 7.3 on Linux. Solution: Update to version 7.3 or later. CVSS Score: 7.8 CVSS Vector: AV:N/AC:L/Au:N/C:N/I:N/A:C
Cross-Ref:	Common Vulnerability Exposure (CVE) ID: CVE-2016-6515 BugTraq ID: 92212 http://www.securityfocus.com/bid/92212 https://www.exploit-db.com/exploits/40888/ https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/X2L6RW34VFNXYNVVN2CN73YAGJ5VMTFU/ FreeBSD Security Advisory: FreeBSD-SA-17:06 https://security.FreeBSD.org/advisories/FreeBSD-SA-17:06.openssh.asc http://packetstormsecurity.com/files/140070/OpenSSH-7.2-Denial-Of-Service.html https://lists.debian.org/debian-lts-announce/2018/09/msg00010.html http://openwall.com/lists/oss-security/2016/08/01/2 RedHat Security Advisories: RHSA-2017:2029 https://access.redhat.com/errata/RHSA-2017:2029 http://www.securitytracker.com/id/1036487 Common Vulnerability Exposure (CVE) ID: CVE-2016-6210 BugTraq ID: 91812 http://www.securityfocus.com/bid/91812 Debian Security Information: DSA-3626 (Google Search) http://www.debian.org/security/2016/dsa-3626 https://www.exploit-db.com/exploits/40113/ https://www.exploit-db.com/exploits/40136/ http://seclists.org/fulldisclosure/2016/Jul/51 https://security.gentoo.org/glsa/201612-18 RedHat Security Advisories: RHSA-2017:2563 https://access.redhat.com/errata/RHSA-2017:2563 http://www.securitytracker.com/id/1036319
Copyright	Copyright (C) 2016 Greenbone AG

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