CVE-2018-10896

cloud-init: default configuration disabled deletion of SSH host keys

Severity Score

7.1

*CVSS v3.1

Exploit Likelihood

*EPSS

Affected Versions

*CPE

Public Exploits

*Multiple Sources

Exploited in Wild

*KEV

Decision

*SSVC

Descriptions

The default cloud-init configuration, in cloud-init 0.6.2 and newer, included "ssh_deletekeys: 0", disabling cloud-init's deletion of ssh host keys. In some environments, this could lead to instances created by cloning a golden master or template system, sharing ssh host keys, and being able to impersonate one another or conduct man-in-the-middle attacks.

La configuración por defecto en cloud-init, en versiones a partir de la 0.6.2, incluía "ssh_deletekeys: 0", deshabilitando la eliminación de cloud-init de claves de host ssh. En algunos entornos, esto podría conducir a que se creen instancias creadas al clonar un sistema golden master o template, a que se compartan claves de host ssh o a que se pueda suplantar a otro o llevar a cabo ataques de Man-in-the-Middle (MitM).

The default cloud-init configuration included "ssh_deletekeys: 0", disabling cloud-init's deletion of ssh host keys. In some environments, this could lead to instances created by cloning a golden master or template system, sharing ssh host keys, and being able to impersonate one another or conduct man-in-the-middle attacks.

The cloud-init packages provide a set of init scripts for cloud instances. Cloud instances need special scripts to run during initialization to retrieve and install SSH keys, and to let the user run various scripts.

*Credits: N/A

CVSS Scores

Attack Vector

Local

Attack Complexity

Low

Privileges Required

Low

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

None

Attack Vector

Local

Attack Complexity

Low

Privileges Required

Low

User Interaction

Required

Scope

Changed

Confidentiality

Low

Integrity

Low

Availability

None

Attack Vector

Local

Attack Complexity

Low

Authentication

None

Confidentiality

Partial

Integrity

Partial

Availability

None

* Common Vulnerability Scoring System

SSVC

Decision:-

Exploitation

Automatable

Tech. Impact

* Organization's Worst-case Scenario

Timeline

2018-05-09 CVE Reserved
2018-08-01 CVE Published
2024-08-05 CVE Updated
2025-07-13 EPSS Updated
---------- Exploited in Wild
---------- KEV Due Date
---------- First Exploit

CWE

CWE-321: Use of Hard-coded Cryptographic Key

CAPEC

References (5)

URL	Tag	Source
https://bugzilla.redhat.com/show_bug.cgi?id=1574338	Issue Tracking

URL	Date	SRC

URL	Date	SRC
https://bugs.launchpad.net/cloud-init/+bug/1781094	2023-02-13
https://bugzilla.redhat.com/show_bug.cgi?id=CVE-2018-10896	2023-02-13

URL	Date	SRC
https://access.redhat.com/security/cve/CVE-2018-10896	2020-09-29
https://bugzilla.redhat.com/show_bug.cgi?id=1598831	2020-09-29

Affected Vendors, Products, and Versions

Vendor		Product				Version		Other		Status
Vendor	Product	Version	Other	Status	<-- -->	Vendor	Product	Version	Other	Status
Canonical Search vendor "Canonical"		Cloud-init Search vendor "Canonical" for product "Cloud-init"				>= 0.6.2 < 18.4 Search vendor "Canonical" for product "Cloud-init" and version " >= 0.6.2 < 18.4"		-		Affected