Bug 1598831 – CVE-2018-10896 cloud-init: default configuration disabled deletion of SSH host keys

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Bug 1598831 - (CVE-2018-10896) CVE-2018-10896 cloud-init: default configuration disabled deletion of SSH host keys

Summary:	CVE-2018-10896 cloud-init: default configuration disabled deletion of SSH hos...

Status:	NEW

Aliases:	CVE-2018-10896

Product:	Security Response
Classification:	Other
Component:	vulnerability (Show other bugs)
Sub Component:
Version:	unspecified
Hardware:	All Linux

Priority	low Severity low
Target Milestone:	---
Target Release:	---
Assigned To:	Red Hat Product Security
QA Contact:
Docs Contact:

URL:
Whiteboard:	impact=low,public=20180706,reported=2...
Keywords:	Security

Depends On:	1574338 1598832 1598833 1598834
Blocks:	1576571
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Reported:	2018-07-06 11:04 EDT by Laura Pardo
Modified:	2018-08-06 20:59 EDT (History)
CC List:	11 users (show)

See Also:
Fixed In Version:
Doc Type:	If docs needed, set a value
Doc Text:	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.
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RHEL 7.3 requirements from Atomic Host:
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Description Laura Pardo 2018-07-06 11:04:16 EDT

A flaw was found in cloud-init. SSH host keys are not regenerated when new VM instances are created in combination with hashicorp packer and cloud-init. This could lead to the Man In The Middle (MITM) attack.


References:
https://bugzilla.redhat.com/show_bug.cgi?id=1574338

Comment 1 Laura Pardo 2018-07-06 11:05:49 EDT

Created cloud-init tracking bugs for this issue:

Affects: epel-6 [bug 1598833]
Affects: fedora-all [bug 1598832]

Comment 5 Doran Moppert 2018-07-10 20:32:13 EDT

Reported upstream:

https://bugs.launchpad.net/cloud-init/+bug/1781094

Comment 7 Doran Moppert 2018-08-06 20:59:01 EDT

Upstream commit now merged to master:

https://git.launchpad.net/cloud-init/commit/?id=e218c597

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