PT-2015-3444 · Openbsd+6 · Openssh+6

Jann Horn

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Published

2015-07-16

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Updated

2026-05-27

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CVE-2015-5600

CVSS v2.0

8.5

High

VectorAV:N/AC:L/Au:N/C:P/I:N/A:C
Name of the Vulnerable Software and Affected Versions OpenSSH versions through 6.9
Description The issue is related to the kbdint next device() function in the OpenSSH sshd service, which does not properly restrict the processing of keyboard-interactive devices within a single connection. This makes it easier for remote attackers to conduct brute-force attacks or cause a denial of service via a long and duplicative list in the ssh -oKbdInteractiveDevices option. The vulnerability allows for unlimited entries within the login time limit, permitting a brute-force attack on weak passwords within the login time period.
Recommendations For OpenSSH versions through 6.9, consider disabling the kbdint next device() function or restricting the use of the ssh -oKbdInteractiveDevices option to minimize the risk of exploitation. Additionally, restrict access to the auth2-chall.c module to prevent abuse. At the moment, there is no information about a newer version that contains a fix for this vulnerability.

Exploit

DoS

Resource Exhaustion

Weakness Enumeration

Related Identifiers

ALT-PU-2016-1023
ALT-PU-2024-3921
ALT-PU-2024-4077
ALT-PU-2024-4467
ALT-PU-2024-9513
BDU:2022-07484
CESA-2015_2088
CESA-2016_0466
CVE-2015-5600
DLA-1500-1
DLA-288-1
MGASA-2015-0295
RHSA-2015:2088
RHSA-2015_2088
RHSA-2016:0466
RHSA-2016_0466
SUSE-SU-2015:1544-1
SUSE-SU-2015:1581-1
SUSE-SU-2015:1695-1
SUSE-SU-2015:1840-1
USN-2710-1
USN-2710-2

Affected Products

Alt Linux
Centos
Junos
Openssh
Red Hat
Suse
Ubuntu