CVE-2016-6515

OpenSSH 7.2 - Denial of Service

Severity Score

7.5

*CVSS v3

Exploit Likelihood

*EPSS

Affected Versions

*CPE

Public Exploits

*Multiple Sources

Exploited in Wild

*KEV

Decision

*SSVC

Descriptions

The auth_password function in auth-passwd.c in sshd in OpenSSH before 7.3 does not limit password lengths for password authentication, which allows remote attackers to cause a denial of service (crypt CPU consumption) via a long string.

La función auth_password en auth-passwd.c en sshd en OpenSSH en versiones anteriores a 7.3 no limita longitudes de contraseña para autenticación de contraseña, lo que permite a atacantes remotos provocar una denegación de servicio (consumo de CPU clave) a través de una cadena larga.

It was found that OpenSSH did not limit password lengths for password authentication. A remote unauthenticated attacker could use this flaw to temporarily trigger high CPU consumption in sshd by sending long passwords.

*Credits: N/A

CVSS Scores

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

None

Availability

High

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

None

Availability

Low

Attack Vector

Network

Attack Complexity

Low

Authentication

None

Confidentiality

None

Integrity

None

Availability

Complete

Attack Vector

Network

Attack Complexity

Medium

Authentication

None

Confidentiality

None

Integrity

None

Availability

Partial

* Common Vulnerability Scoring System

SSVC

Decision:-

Exploitation

Automatable

Tech. Impact

* Organization's Worst-case Scenario

Timeline

2016-08-01 CVE Reserved
2016-08-07 CVE Published
2017-09-10 First Exploit
2024-08-06 CVE Updated
2024-08-12 EPSS Updated
---------- Exploited in Wild
---------- KEV Due Date

CWE

CWE-20: Improper Input Validation
CWE-770: Allocation of Resources Without Limits or Throttling

CAPEC

References (18)

URL	Tag	Source
http://openwall.com/lists/oss-security/2016/08/01/2	Mailing List
http://packetstormsecurity.com/files/140070/OpenSSH-7.2-Denial-Of-Service.html
http://www.oracle.com/technetwork/security-advisory/cpuoct2017-3236626.html
http://www.securityfocus.com/bid/92212	Vdb Entry
http://www.securitytracker.com/id/1036487	Vdb Entry
https://cert-portal.siemens.com/productcert/pdf/ssa-412672.pdf
https://cert-portal.siemens.com/productcert/pdf/ssa-676336.pdf
https://lists.debian.org/debian-lts-announce/2018/09/msg00010.html	Mailing List
https://security.netapp.com/advisory/ntap-20171130-0003
https://support.hpe.com/hpsc/doc/public/display?docLocale=en_US&docId=emr_na-hpesbhf03779en_us

URL	Date	SRC
https://www.exploit-db.com/exploits/40888	2024-08-06
https://github.com/opsxcq/exploit-CVE-2016-6515	2017-09-10

URL	Date	SRC
https://github.com/openssh/openssh-portable/commit/fcd135c9df440bcd2d5870405ad3311743d78d97	2023-11-07

URL	Date	SRC
https://access.redhat.com/errata/RHSA-2017:2029	2023-11-07
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/X2L6RW34VFNXYNVVN2CN73YAGJ5VMTFU	2023-11-07
https://security.FreeBSD.org/advisories/FreeBSD-SA-17:06.openssh.asc	2023-11-07
https://access.redhat.com/security/cve/CVE-2016-6515	2017-08-01
https://bugzilla.redhat.com/show_bug.cgi?id=1364935	2017-08-01

Affected Vendors, Products, and Versions

Vendor		Product				Version		Other		Status
Vendor	Product	Version	Other	Status	<-- -->	Vendor	Product	Version	Other	Status
Openbsd Search vendor "Openbsd"		Openssh Search vendor "Openbsd" for product "Openssh"				<= 7.2 Search vendor "Openbsd" for product "Openssh" and version " <= 7.2"		p2		Affected
Fedoraproject Search vendor "Fedoraproject"		Fedora Search vendor "Fedoraproject" for product "Fedora"				24 Search vendor "Fedoraproject" for product "Fedora" and version "24"		-		Affected