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Bug 589088 (CVE-2016-6210) - <net-misc/openssh-7.3_p1: User enumeration via covert timing channel
Summary: <net-misc/openssh-7.3_p1: User enumeration via covert timing channel
Alias: CVE-2016-6210
Product: Gentoo Security
Classification: Unclassified
Component: Vulnerabilities (show other bugs)
Hardware: All Linux
: Normal minor (vote)
Assignee: Gentoo Security
Whiteboard: A4 [glsa glsa blocked cve]
Depends on: 590202
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Reported: 2016-07-18 15:38 UTC by Agostino Sarubbo
Modified: 2016-12-07 10:32 UTC (History)
1 user (show)

See Also:
Package list:
Runtime testing required: ---


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Description Agostino Sarubbo gentoo-dev 2016-07-18 15:38:11 UTC
From ${URL} :

When SSHD tries to authenticate a non-existing user, it will pick up a fake password structure hardcoded in the SSHD source code. On this hard coded  
password  structure  the password hash is based on BLOWFISH ($2) algorithm. If real users passwords are hashed using SHA256/SHA512, then sending large 
passwords (10KB)  will result in shorter response time from the server for non-existing users. This allows remote attacker to enumerate existing users on 
system logging via SSHD.

Published in:

@maintainer(s): after the bump, in case we need to stabilize the package, please let us know if it is ready for the stabilization or not.
Comment 1 GLSAMaker/CVETool Bot gentoo-dev 2016-12-07 10:32:53 UTC
This issue was resolved and addressed in
 GLSA 201612-18 at
by GLSA coordinator Aaron Bauman (b-man).