Bug 813672 (CVE-2016-20012)

Summary:	net-misc/openssh: user enumeration if pubkey and user are known (CVE-2016-20012)
Product:	Gentoo Security	Reporter:	John Helmert III <ajak>
Component:	Vulnerabilities	Assignee:	Gentoo Security <security>
Status:	RESOLVED UPSTREAM
Severity:	minor	CC:	base-system
Priority:	Normal
Version:	unspecified
Hardware:	All
OS:	Linux
URL:	https://github.com/openssh/openssh-portable/blob/d0fffc88c8fe90c1815c6f4097bc8cbcabc0f3dd/auth2-pubkey.c#L261-L265
Whiteboard:	A4 [upstream]
Package list:		Runtime testing required:	---

Description John Helmert III archtester

2021-09-18 17:39:32 UTC

CVE-2016-20012:

OpenSSH through 8.7 allows remote attackers, who have a suspicion that a certain combination of username and public key is known to an SSH server, to test whether this suspicion is correct. This occurs because a challenge is sent only when that combination could be valid for a login session.

Potential patch: https://github.com/openssh/openssh-portable/pull/270

Comment 1 John Helmert III archtester

2022-08-17 16:27:54 UTC

Upstream says this won't be fixed in the near future.