The kbdint_next_device function in auth2-chall.c in sshd in OpenSSH through...

Vulnerability Description

The kbdint_next_device function in auth2-chall.c in sshd in OpenSSH through 6.9 does not properly restrict the processing of keyboard-interactive devices within a single connection, which makes it easier for remote attackers to conduct brute-force attacks or cause a denial of service (CPU consumption) via a long and duplicative list in the ssh -oKbdInteractiveDevices option, as demonstrated by a modified client that provides a different password for each pam element on this list.

References

• http://www.oracle.com/technetwork/topics/security/ovmbulletinjul2016-3090546.html
• http://www.ubuntu.com/usn/USN-2710-2
• http://lists.fedoraproject.org/pipermail/package-announce/2015-August/165170.html
• http://www.oracle.com/technetwork/security-advisory/cpujul2018-4258247.html
• https://h20566.www2.hpe.com/portal/site/hpsc/public/kb/docDisplay?docId=emr_na-c05157667
• https://h20566.www2.hpe.com/portal/site/hpsc/public/kb/docDisplay?docId=emr_na-c05128992
• http://www.oracle.com/technetwork/topics/security/linuxbulletinapr2016-2952096.html
• http://www.oracle.com/technetwork/security-advisory/cpujul2016-2881720.html
• https://security.gentoo.org/glsa/201512-04
• https://kc.mcafee.com/corporate/index?page=content&id=SB10136
• https://security.netapp.com/advisory/ntap-20151106-0001/
• http://rhn.redhat.com/errata/RHSA-2016-0466.html
• http://cvsweb.openbsd.org/cgi-bin/cvsweb/src/usr.bin/ssh/auth2-chall.c.diff?r1=1.42&r2=1.43&f=h
• http://www.oracle.com/technetwork/topics/security/linuxbulletinoct2015-2719645.html
• http://kb.juniper.net/InfoCenter/index?page=content&id=JSA10697
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• http://cvsweb.openbsd.org/cgi-bin/cvsweb/src/usr.bin/ssh/auth2-chall.c
• https://kc.mcafee.com/corporate/index?page=content&id=SB10157
• http://www.securityfocus.com/bid/75990
• http://www.securityfocus.com/bid/91787
• https://h20564.www2.hpe.com/portal/site/hpsc/public/kb/docDisplay?docId=emr_na-c04952480
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• http://www.securityfocus.com/bid/92012
• https://support.apple.com/kb/HT205031
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• http://openwall.com/lists/oss-security/2015/07/23/4
• http://www.ubuntu.com/usn/USN-2710-1
• http://lists.fedoraproject.org/pipermail/package-announce/2015-July/162955.html
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• https://cert-portal.siemens.com/productcert/pdf/ssa-412672.pdf