The option AllowUsers of /etc/ssh/sshd_config stopped working.
Any user can log through ssh even not present in this option.
Before the upgrade everything worked fine.
I tested the same sshd_config file in my OpenBSD box and there everything worked as expected.
Thanks in advance for your time and help.
# /usr/sbin/sshd -D -f /etc/ssh/sshd_config -d
debug1: sshd version OpenSSH_6.9, OpenSSL 1.0.2d 9 Jul 2015
debug1: private host key #0: ssh-rsa SHA256:Qt/Tvla7baMNHE6zEeKElm9sNWGlRYUjuIDT/tq7D/c
debug1: private host key #1: ssh-dss SHA256:jZ4QK8dI46HvGFEMgPnN1C9jcVDYIRSk0UKZhT7fjzM
debug1: private host key #2: ecdsa-sha2-nistp521 SHA256:tpsp3EYEixbFgA4TVXiZxxu2ZGDwl4GTGYcBlnk+XiY
debug1: rexec_argv[0]='/usr/sbin/sshd'
debug1: rexec_argv[1]='-D'
debug1: rexec_argv[2]='-f'
debug1: rexec_argv[3]='/etc/ssh/sshd_config'
debug1: rexec_argv[4]='-d'
Set /proc/self/oom_score_adj from 0 to -1000
debug1: Bind to port 22 on 0.0.0.0.
Server listening on 0.0.0.0 port 22.
debug1: Bind to port 22 on ::.
Server listening on :: port 22.
debug1: Server will not fork when running in debugging mode.
debug1: rexec start in 5 out 5 newsock 5 pipe -1 sock 8
debug1: inetd sockets after dupping: 3, 3
Connection from 200.137.21.34 port 53540 on 192.168.1.3 port 22
debug1: Client protocol version 2.0; client software version OpenSSH_6.6.1p1 Ubuntu-2ubuntu2
debug1: match: OpenSSH_6.6.1p1 Ubuntu-2ubuntu2 pat OpenSSH_6.6.1* compat 0x04000000
debug1: Enabling compatibility mode for protocol 2.0
debug1: Local version string SSH-2.0-OpenSSH_6.9p1 Debian-2+b1
debug1: permanently_set_uid: 112/65534 [preauth]
debug1: list_hostkey_types: ssh-rsa,ssh-dss,ecdsa-sha2-nistp521 [preauth]
debug1: SSH2_MSG_KEXINIT sent [preauth]
debug1: SSH2_MSG_KEXINIT received [preauth]
debug1: kex: client->server
aes256-gcm@openssh.com <implicit> none [preauth]
debug1: kex: server->client
aes256-gcm@openssh.com <implicit> none [preauth]
debug1: expecting SSH2_MSG_KEX_ECDH_INIT [preauth]
debug1: SSH2_MSG_NEWKEYS sent [preauth]
debug1: expecting SSH2_MSG_NEWKEYS [preauth]
debug1: SSH2_MSG_NEWKEYS received [preauth]
debug1: KEX done [preauth]
debug1: userauth-request for user user1 service ssh-connection method none [preauth]
debug1: attempt 0 failures 0 [preauth]
debug1: user user1 does not match group list hg-users at line 93
debug1: PAM: initializing for "user1"
debug1: PAM: setting PAM_RHOST to "200.137.21.34"
debug1: PAM: setting PAM_TTY to "ssh"
debug1: userauth-request for user user1 service ssh-connection method publickey [preauth]
debug1: attempt 1 failures 0 [preauth]
debug1: test whether pkalg/pkblob are acceptable [preauth]
debug1: temporarily_use_uid: 1000/1000 (e=0/0)
debug1: trying public key file /home/user1/.ssh/authorized_keys
debug1: fd 4 clearing O_NONBLOCK
debug1: restore_uid: 0/0
debug1: temporarily_use_uid: 1000/1000 (e=0/0)
debug1: trying public key file /home/user1/.ssh/authorized_keys2
debug1: Could not open authorized keys '/home/user1/.ssh/authorized_keys2': No such file or directory
debug1: restore_uid: 0/0
Failed publickey for user1 from 200.137.21.34 port 53540 ssh2: RSA SHA256:Rf4KIuZGFt5aUAnoA890Why0iSbfItRf/shVfCEEmuw
debug1: userauth-request for user user1 service ssh-connection method password [preauth]
debug1: attempt 2 failures 1 [preauth]
debug1: PAM: password authentication accepted for user1
debug1: do_pam_account: called
Accepted password for user1 from 200.137.21.34 port 53540 ssh2
debug1: monitor_child_preauth: user1 has been authenticated by privileged process
debug1: monitor_read_log: child log fd closed
debug1: PAM: establishing credentials
User child is on pid 13122
debug1: SELinux support disabled
debug1: PAM: establishing credentials
debug1: permanently_set_uid: 1000/1000
debug1: ssh_packet_set_postauth: called
debug1: Entering interactive session for SSH2.
debug1: server_init_dispatch_20
debug1: server_input_channel_open: ctype session rchan 0 win 1048576 max 16384
debug1: input_session_request
debug1: channel 0: new [server-session]
debug1: session_new: session 0
debug1: session_open: channel 0
debug1: session_open: session 0: link with channel 0
debug1: server_input_channel_open: confirm session
debug1: server_input_global_request: rtype
no-more-sessions@openssh.com want_reply 0
debug1: server_input_channel_req: channel 0 request pty-req reply 1
debug1: session_by_channel: session 0 channel 0
debug1: session_input_channel_req: session 0 req pty-req
debug1: Allocating pty.
debug1: session_new: session 0
debug1: SELinux support disabled
debug1: session_pty_req: session 0 alloc /dev/pts/4
debug1: server_input_channel_req: channel 0 request env reply 0
debug1: session_by_channel: session 0 channel 0
debug1: session_input_channel_req: session 0 req env
debug1: server_input_channel_req: channel 0 request shell reply 1
debug1: session_by_channel: session 0 channel 0
debug1: session_input_channel_req: session 0 req shell
Starting session: shell on pts/4 for user1 from 200.137.21.34 port 53540
debug1: Setting controlling tty using TIOCSCTTY.
debug1: Received SIGCHLD.
debug1: session_by_pid: pid 13123
debug1: session_exit_message: session 0 channel 0 pid 13123
debug1: session_exit_message: release channel 0
debug1: session_by_tty: session 0 tty /dev/pts/4
debug1: session_pty_cleanup: session 0 release /dev/pts/4
debug1: session_by_channel: session 0 channel 0
debug1: session_close_by_channel: channel 0 child 0
debug1: session_close: session 0 pid 0
debug1: channel 0: free: server-session, nchannels 1
Received disconnect from
200.137.21.34: 11: disconnected by user
Disconnected from 200.137.21.34
debug1: do_cleanup
debug1: do_cleanup
debug1: PAM: cleanup
debug1: PAM: closing session
debug1: PAM: deleting credentials
debug1: audit_event: unhandled event 12
==============================================================
sshd_config:
# Package generated configuration file
# See the sshd_config(5) manpage for details
# What ports, IPs and protocols we listen for
Port 22
# Use these options to restrict which interfaces/protocols sshd will bind to
#ListenAddress ::
#ListenAddress 0.0.0.0
Protocol 2
# HostKeys for protocol version 2
HostKey /etc/ssh/ssh_host_rsa_key
HostKey /etc/ssh/ssh_host_dsa_key
HostKey /etc/ssh/ssh_host_ecdsa_key
#Privilege Separation is turned on for security
UsePrivilegeSeparation yes
# Lifetime and size of ephemeral version 1 server key
KeyRegenerationInterval 3600
ServerKeyBits 4096
# Logging
SyslogFacility AUTH
LogLevel INFO
# Authentication:
LoginGraceTime 120
#PermitRootLogin without-password
PermitRootLogin no
StrictModes yes
RSAAuthentication yes
PubkeyAuthentication yes
#AuthorizedKeysFile %h/.ssh/authorized_keys
# Don't read the user's ~/.rhosts and ~/.shosts files
IgnoreRhosts yes
# For this to work you will also need host keys in /etc/ssh_known_hosts
RhostsRSAAuthentication no
# similar for protocol version 2
HostbasedAuthentication no
# Uncomment if you don't trust ~/.ssh/known_hosts for RhostsRSAAuthentication
#IgnoreUserKnownHosts yes
# To enable empty passwords, change to yes (NOT RECOMMENDED)
PermitEmptyPasswords no
# Change to yes to enable challenge-response passwords (beware issues with
# some PAM modules and threads)
ChallengeResponseAuthentication no
# Change to no to disable tunnelled clear text passwords
#PasswordAuthentication yes
# Kerberos options
#KerberosAuthentication no
#KerberosGetAFSToken no
#KerberosOrLocalPasswd yes
#KerberosTicketCleanup yes
# GSSAPI options
#GSSAPIAuthentication no
#GSSAPICleanupCredentials yes
X11Forwarding yes
X11DisplayOffset 10
PrintMotd no
PrintLastLog yes
TCPKeepAlive yes
Ciphers aes256-cbc,
aes256-gcm@openssh.com,aes256-cbc
MACs hmac-sha2-512,hmac-sha2-256
#UseLogin no
#MaxStartups 10:30:60
#Banner /etc/
issue.net# Allow client to pass locale environment variables
AcceptEnv LANG LC_*
Subsystem sftp /usr/lib/openssh/sftp-server
# Set this to 'yes' to enable PAM authentication, account processing,
# and session processing. If this is enabled, PAM authentication will
# be allowed through the ChallengeResponseAuthentication and
# PasswordAuthentication. Depending on your PAM configuration,
# PAM authentication via ChallengeResponseAuthentication may bypass
# the setting of "PermitRootLogin without-password".
# If you just want the PAM account and session checks to run without
# PAM authentication, then enable this but set PasswordAuthentication
# and ChallengeResponseAuthentication to 'no'.
UsePAM yes
AllowUsers remoteguest