#StackBounty: #networking #ssh #proxy #git #firewall How can I see the proxy configurations of an SSH command in git bash?

Bounty: 50

I’m having issues with SSHing through a corporate proxy.

In my Windows environment – SSH works fine:

$ ssh -v git@github.com
OpenSSH_7.5p1, OpenSSL 1.0.2k  26 Jan 2017
debug1: Reading configuration data /c/Users/davidj/.ssh/config
debug1: /c/Users/davidj/.ssh/config line 2: Applying options for github.com
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: Connecting to github.com [192.30.255.112] port 22.
debug1: Connection established.
...

Now in my Windows taskbar, there’s an ISA Server Firewall client. If I uncheck ‘Enable Microsoft Firewall Client for ISA Server’ then my SSH attempt will fail.

$ ssh -v git@github.com
OpenSSH_7.5p1, OpenSSL 1.0.2k  26 Jan 2017
debug1: Reading configuration data /c/Users/davidj/.ssh/config
debug1: /c/Users/davidj/.ssh/config line 2: Applying options for github.com
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: Connecting to github.com [192.30.255.112] port 22.
debug1: connect to address 192.30.255.112 port 22: Connection timed out

So this is all well and good for working in the Windows environment – I just need to enable the firewall client.

My problem is that I’m trying to work within a Ubuntu VM on Virtual Box.

The Virtual Box network adapter is NAT, with no port forwarding.

In the VM HTTP traffic works fine, so long as I’ve set network proxy for HTTP and HTTPS in Ubuntu.

However, SSH here will give me connection refused:

david@david-VirtualBox:~$ ssh -vvv git@github.com
OpenSSH_7.2p2 Ubuntu-4ubuntu2.2, OpenSSL 1.0.2g  1 Mar 2016
debug1: Reading configuration data /home/david/.ssh/config
debug1: /home/david/.ssh/config line 2: Applying options for github.com
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: /etc/ssh/ssh_config line 19: Applying options for *
debug2: resolving "github.com" port 22
debug2: ssh_connect_direct: needpriv 0
debug1: Connecting to github.com [192.30.255.113] port 22.

Is there a way of debugging here how my Windows is able to SSH to the outside world?


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#StackBounty: #ssh ss/config file not working but ssh works

Bounty: 100

I am trying to login to final_host from localhost via an intermediate hop, i.e:

localhost -> hop -> final_host

This works:

localhost:~$ ssh -t user@hop "ssh user@final_host"

This also works:

localhost:~$ ssh user@hop
hop:~$ ssh user@final_host
finalhost:~$

But this doesn’t:

localhost:~$ ssh -J user@hop_ip "ssh user@final_host_ip" -vvv
OpenSSH_7.6p1, LibreSSL 2.6.2
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: /etc/ssh/ssh_config line 48: Applying options for *
debug1: Setting implicit ProxyCommand from ProxyJump: ssh -l user -vvv -W '[%h]:%p' hop_ip
debug1: Executing proxy command: exec ssh -l user -vvv -W '[final_host_ip]:22' hop_ip
debug1: key_load_public: No such file or directory
debug1: identity file /Users/user/.ssh/id_rsa type -1
debug1: key_load_public: No such file or directory
debug1: identity file /Users/user/.ssh/id_rsa-cert type -1
debug1: key_load_public: No such file or directory
debug1: identity file /Users/user/.ssh/id_dsa type -1
debug1: key_load_public: No such file or directory
debug1: identity file /Users/user/.ssh/id_dsa-cert type -1
debug1: key_load_public: No such file or directory
debug1: identity file /Users/user/.ssh/id_ecdsa type -1
debug1: key_load_public: No such file or directory
debug1: identity file /Users/user/.ssh/id_ecdsa-cert type -1
debug1: key_load_public: No such file or directory
debug1: identity file /Users/user/.ssh/id_ed25519 type -1
debug1: key_load_public: No such file or directory
debug1: identity file /Users/user/.ssh/id_ed25519-cert type -1
debug1: Local version string SSH-2.0-OpenSSH_7.6
debug1: permanently_drop_suid: 501
OpenSSH_7.6p1, LibreSSL 2.6.2
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: /etc/ssh/ssh_config line 48: Applying options for *
debug2: ssh_connect_direct: needpriv 0
debug1: Connecting to hop_ip port 22.
debug1: Connection established.
debug1: key_load_public: No such file or directory
debug1: identity file /Users/user/.ssh/id_rsa type -1
debug1: key_load_public: No such file or directory
debug1: identity file /Users/user/.ssh/id_rsa-cert type -1
debug1: key_load_public: No such file or directory
debug1: identity file /Users/user/.ssh/id_dsa type -1
debug1: key_load_public: No such file or directory
debug1: identity file /Users/user/.ssh/id_dsa-cert type -1
debug1: key_load_public: No such file or directory
debug1: identity file /Users/user/.ssh/id_ecdsa type -1
debug1: key_load_public: No such file or directory
debug1: identity file /Users/user/.ssh/id_ecdsa-cert type -1
debug1: key_load_public: No such file or directory
debug1: identity file /Users/user/.ssh/id_ed25519 type -1
debug1: key_load_public: No such file or directory
debug1: identity file /Users/user/.ssh/id_ed25519-cert type -1
debug1: Local version string SSH-2.0-OpenSSH_7.6
debug1: Remote protocol version 2.0, remote software version OpenSSH_7.2p2 Ubuntu-4ubuntu2.4
debug1: match: OpenSSH_7.2p2 Ubuntu-4ubuntu2.4 pat OpenSSH* compat 0x04000000
debug3: fd 5 is O_NONBLOCK
debug1: Authenticating to hop_ip:22 as 'user'
debug3: hostkeys_foreach: reading file "/Users/user/.ssh/known_hosts"
debug3: record_hostkey: found key type ED25519 in file /Users/user/.ssh/known_hosts:1
debug3: load_hostkeys: loaded 1 keys from hop_ip
debug3: order_hostkeyalgs: prefer hostkeyalgs: ssh-ed25519-cert-v01@openssh.com,ssh-ed25519
debug3: send packet: type 20
debug1: SSH2_MSG_KEXINIT sent
debug3: receive packet: type 20
debug1: SSH2_MSG_KEXINIT received
debug2: local client KEXINIT proposal
debug2: KEX algorithms: curve25519-sha256,curve25519-sha256@libssh.org,ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,diffie-hellman-group-exchange-sha256,diffie-hellman-group16-sha512,diffie-hellman-group18-sha512,diffie-hellman-group-exchange-sha1,diffie-hellman-group14-sha256,diffie-hellman-group14-sha1,ext-info-c
debug2: host key algorithms: ssh-ed25519-cert-v01@openssh.com,ssh-ed25519,ecdsa-sha2-nistp256-cert-v01@openssh.com,ecdsa-sha2-nistp384-cert-v01@openssh.com,ecdsa-sha2-nistp521-cert-v01@openssh.com,ssh-rsa-cert-v01@openssh.com,ecdsa-sha2-nistp256,ecdsa-sha2-nistp384,ecdsa-sha2-nistp521,rsa-sha2-512,rsa-sha2-256,ssh-rsa
debug2: ciphers ctos: chacha20-poly1305@openssh.com,aes128-ctr,aes192-ctr,aes256-ctr,aes128-gcm@openssh.com,aes256-gcm@openssh.com
debug2: ciphers stoc: chacha20-poly1305@openssh.com,aes128-ctr,aes192-ctr,aes256-ctr,aes128-gcm@openssh.com,aes256-gcm@openssh.com
debug2: MACs ctos: umac-64-etm@openssh.com,umac-128-etm@openssh.com,hmac-sha2-256-etm@openssh.com,hmac-sha2-512-etm@openssh.com,hmac-sha1-etm@openssh.com,umac-64@openssh.com,umac-128@openssh.com,hmac-sha2-256,hmac-sha2-512,hmac-sha1
debug2: MACs stoc: umac-64-etm@openssh.com,umac-128-etm@openssh.com,hmac-sha2-256-etm@openssh.com,hmac-sha2-512-etm@openssh.com,hmac-sha1-etm@openssh.com,umac-64@openssh.com,umac-128@openssh.com,hmac-sha2-256,hmac-sha2-512,hmac-sha1
debug2: compression ctos: none,zlib@openssh.com,zlib
debug2: compression stoc: none,zlib@openssh.com,zlib
debug2: languages ctos:
debug2: languages stoc:
debug2: first_kex_follows 0
debug2: reserved 0
debug2: peer server KEXINIT proposal
debug2: KEX algorithms: curve25519-sha256@libssh.org,ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,diffie-hellman-group-exchange-sha256,diffie-hellman-group14-sha1
debug2: host key algorithms: ssh-rsa,rsa-sha2-512,rsa-sha2-256,ssh-ed25519
debug2: ciphers ctos: chacha20-poly1305@openssh.com,aes128-ctr,aes192-ctr,aes256-ctr,aes128-gcm@openssh.com,aes256-gcm@openssh.com
debug2: ciphers stoc: chacha20-poly1305@openssh.com,aes128-ctr,aes192-ctr,aes256-ctr,aes128-gcm@openssh.com,aes256-gcm@openssh.com
debug2: MACs ctos: umac-64-etm@openssh.com,umac-128-etm@openssh.com,hmac-sha2-256-etm@openssh.com,hmac-sha2-512-etm@openssh.com,hmac-sha1-etm@openssh.com,umac-64@openssh.com,umac-128@openssh.com,hmac-sha2-256,hmac-sha2-512,hmac-sha1
debug2: MACs stoc: umac-64-etm@openssh.com,umac-128-etm@openssh.com,hmac-sha2-256-etm@openssh.com,hmac-sha2-512-etm@openssh.com,hmac-sha1-etm@openssh.com,umac-64@openssh.com,umac-128@openssh.com,hmac-sha2-256,hmac-sha2-512,hmac-sha1
debug2: compression ctos: none,zlib@openssh.com
debug2: compression stoc: none,zlib@openssh.com
debug2: languages ctos:
debug2: languages stoc:
debug2: first_kex_follows 0
debug2: reserved 0
debug1: kex: algorithm: curve25519-sha256@libssh.org
debug1: kex: host key algorithm: ssh-ed25519
debug1: kex: server->client cipher: chacha20-poly1305@openssh.com MAC: <implicit> compression: none
debug1: kex: client->server cipher: chacha20-poly1305@openssh.com MAC: <implicit> compression: none
debug3: send packet: type 30
debug1: expecting SSH2_MSG_KEX_ECDH_REPLY
debug3: receive packet: type 31
debug1: Server host key: ssh-ed25519 SHA256:c18UMgj7nokTZJHMGnbsOgxDHlIZc2r184efDHtoTLE
debug3: hostkeys_foreach: reading file "/Users/user/.ssh/known_hosts"
debug3: record_hostkey: found key type ED25519 in file /Users/user/.ssh/known_hosts:1
debug3: load_hostkeys: loaded 1 keys from hop_ip
debug1: Host 'hop_ip' is known and matches the ED25519 host key.
debug1: Found key in /Users/user/.ssh/known_hosts:1
debug3: send packet: type 21
debug2: set_newkeys: mode 1
debug1: rekey after 134217728 blocks
debug1: SSH2_MSG_NEWKEYS sent
debug1: expecting SSH2_MSG_NEWKEYS
debug3: receive packet: type 21
debug1: SSH2_MSG_NEWKEYS received
debug2: set_newkeys: mode 0
debug1: rekey after 134217728 blocks
debug2: key: server_key_folder/.ssh/id_rsa (0x7f953cc00d70), agent
debug2: key: /Users/user/.ssh/id_rsa (0x0)
debug2: key: /Users/user/.ssh/id_dsa (0x0)
debug2: key: /Users/user/.ssh/id_ecdsa (0x0)
debug2: key: /Users/user/.ssh/id_ed25519 (0x0)
debug3: send packet: type 5
debug3: receive packet: type 7
debug1: SSH2_MSG_EXT_INFO received
debug1: kex_input_ext_info: server-sig-algs=<rsa-sha2-256,rsa-sha2-512>
debug3: receive packet: type 6
debug2: service_accept: ssh-userauth
debug1: SSH2_MSG_SERVICE_ACCEPT received
debug3: send packet: type 50
debug3: receive packet: type 51
debug1: Authentications that can continue: publickey,password
debug3: start over, passed a different list publickey,password
debug3: preferred publickey,keyboard-interactive,password
debug3: authmethod_lookup publickey
debug3: remaining preferred: keyboard-interactive,password
debug3: authmethod_is_enabled publickey
debug1: Next authentication method: publickey
debug1: Offering public key: RSA SHA256:IhOfM2s2i/vFgY/Mj962CoNez631HDIMDRjxFvDhOEI server_key_folder/.ssh/id_rsa
debug3: send_pubkey_test
debug3: send packet: type 50
debug2: we sent a publickey packet, wait for reply
debug3: receive packet: type 60
debug1: Server accepts key: pkalg rsa-sha2-512 blen 279
debug2: input_userauth_pk_ok: fp SHA256:IhOfM2s2i/vFgY/Mj963CoNez631HDIMDRvxFvDhOEI
debug3: sign_and_send_pubkey: RSA SHA256:IhOfM2s2i/vFgY/Mj963CoNez631HDIMDRvxFvDhOEI
debug3: send packet: type 50
debug3: receive packet: type 52
debug1: Authentication succeeded (publickey).
Authenticated to hop_ip ([hop_ip]:22).
debug3: ssh_init_stdio_forwarding: final_host_ip:22
debug1: channel_connect_stdio_fwd final_host_ip:22
debug1: channel 0: new [stdio-forward]
debug2: fd 7 setting O_NONBLOCK
debug2: fd 8 setting O_NONBLOCK
debug1: getpeername failed: Bad file descriptor
debug3: send packet: type 90
debug2: fd 5 setting TCP_NODELAY
debug3: ssh_packet_set_tos: set IP_TOS 0x10
debug1: Requesting no-more-sessions@openssh.com
debug3: send packet: type 80
debug1: Entering interactive session.
debug1: pledge: network
debug3: receive packet: type 80
debug1: client_input_global_request: rtype hostkeys-00@openssh.com want_reply 0
debug3: receive packet: type 91
debug2: channel_input_open_confirmation: channel 0: callback start
debug2: channel_input_open_confirmation: channel 0: callback done
debug2: channel 0: open confirm rwindow 2097152 rmax 32768
debug1: ssh_exchange_identification: 33]1337;PushKeyLabels=fish_%self33]1337;SetKeyLabel=F2=GitSSH-2.0-OpenSSH_7.2p2 Ubuntu-4ubuntu2.4


debug1: ssh_exchange_identification:
debug1: ssh_exchange_identification: 24n��3�30d206206�235A6
debug1: ssh_exchange_identification: ly1305@openssh.com,aes128-ctr,aes192-ctr,aes256-ctr,aes128-gcm@openssh.com,aes256-gcm@openssh.com
debug1: ssh_exchange_identification: sh.com,hmac-sha2-256-etm@openssh.com,hmac-sha2-512-etm@openssh.com,hmac-sha1-etm@openssh.com,umac-64@openssh.com,umac-128@openssh.com,hmac-sha2-256,hmac-sha2-512,hmac-sha1
debug3: receive packet: type 98
debug1: client_input_channel_req: channel 0 rtype keepalive@openssh.com reply 1
debug3: send packet: type 100
debug3: receive packet: type 96
debug2: channel 0: rcvd eof
debug2: channel 0: output open -> drain
debug2: channel 0: obuf empty
debug2: channel 0: close_write
debug2: channel 0: output drain -> closed
debug1: channel 0: FORCE input drain
debug2: channel 0: ibuf empty
debug2: channel 0: send eof
debug3: send packet: type 96
debug2: channel 0: input drain -> closed
debug3: receive packet: type 97
debug2: channel 0: rcvd close
debug3: channel 0: will not send data after close
debug2: channel 0: almost dead
debug2: channel 0: gc: notify user
debug1: stdio forwarding: done
ssh_exchange_identification: Connection closed by remote host

It gets stuck for a while before closing the connection. Using a config file with ProxyJump, ProxyCommand -W or ProxyCommand + nc also doesn’t work and gets stuck at the same point. Additionally this stopped working at some point, I was able to use ProxyCommand in the past and it suddenly stopped working one day without apparent config change from my side. What could be going on here and what can I do to debug further?

EDIT: I should point out that other users of the same system are able to login without issue via config file so the problem is most likely local.


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#StackBounty: #ssh #connection SSH server connects, but does not open a shell session

Bounty: 100

I have a server, where I can login using SSH, but do not get a shell (anymore). What can I do to login to a minimal shell to debug the issue? Here is the log of ssh -vvvv

debug1: SSH2_MSG_SERVICE_ACCEPT received
debug1: Authentications that can continue: publickey,password
debug1: Next authentication method: publickey
debug1: Offering ED25519 public key: user@myhost
debug1: Authentications that can continue: publickey,password
debug1: Offering RSA public key: /home/user/.ssh/id_rsa
debug1: Server accepts key: pkalg ssh-rsa blen 277
debug1: Authentication succeeded (publickey).
Authenticated to remotehost ([x.x.x.x]:22).
debug1: channel 0: new [client-session]
debug1: Requesting no-more-sessions@openssh.com
debug1: Entering interactive session.
debug1: pledge: network

Normally a session would continue with

debug3: receive packet: type 80
debug1: client_input_global_request: rtype hostkeys-00@openssh.com want_reply 0
debug3: receive packet: type 91
debug2: channel_input_open_confirmation: channel 0: callback start

But here ssh just hangs.

How can I get a login shell? I tried ssh -t user@host /bin/sh but it did not work.

I am not sure if something in the ssh server is wrong (maybe waiting for rDNS resolution while there are network errors?) or if some login shell script is blocking the shell.


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#StackBounty: #linux #ssh #kill Work around ssh does not forward signal

Bounty: 100

How can I work around the problem that ssh does not forward the SIGTERM signal?

I want print-signal.py to terminate of the ssh root@localhost process terminates:

ssh root@localhost /root/print-signal.py

Unfortunately only the ssh process itself gets the signal, not the remote command (print-signal.py). The remote command does not terminate 🙁

Since openssh does not forward the SIGTERM to the remote command, I am searching for a work-around.

How to terminate print-signal.py if ssh root@localhost … terminates?

This is a follow-up question to: Forwarding SIGTERM over ssh


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#StackBounty: #ssh #tunnel #http-proxy Use SSH to Create an HTTP Proxy without browser

Bounty: 50

I am trying to reach an HTTP(S) website from my device’s browser. My Device can get to that website only through a double SSH tunnel.

Using this technique, I’m able to set up my Firefox browser to successfully proxy through an SSH tunnel on a server of mine called SERVER1.

However, SERVER1 can’t get to the website that I need. Luckily, SERVER1 can SSH to another SERVER2 who can.

Now, I could run:

SERVER1 $ ssh -D 12345 myuser@SERVER2

and create yet another tunnel from SERVER1 to SERVER2, but I’m not clear on how to do the “firefox” part without firefox on SERVER1.

On top of that, the website is on a non standard port (let’s say 8765) so I’m not sure the export http_proxy would work.

How would I go about it? Thanks


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#StackBounty: #tls #ssh #ports #windows-10 Minimal usage in Windows10 justify filtering all ports besides 22, 80, 443?

Bounty: 50

I use Windows 10 home in my personal computer. I went into cmd and ran:

netstat -a

I saw a large list of ports that are on “LISTEN” mode and some others I couldn’t recognize their state as I never learned much Information Security and I just want to filter ports I don’t use because I might install Windows software that might listen on them without being aware to that.

Will you agree that minimal usage in Windows10 (SSH via WSL/Putty, web surfing and some PC games requiring web connection and sometimes TeamViewer) justify filtering of all ports besides 22, 80, 443?

In my VPS for example (the one I login to with Putty SSH tunnel, I filtered all ports beside 22, 25 (for Postfix), 80, 443 and 9000 for PHP-FPM) and I wonder if my Windows 10 (on which I don’t use port 25 or 9000) should also be that “fortified” by means of port filtering.


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#StackBounty: #ubuntu #ssh #motd Why does SSH kill the colour in my /etc/update-motd.d/ script when force_color_prompt=yes is set in ~/…

Bounty: 50

I have an MOTD script installed in /etc/update-motd.d that works properly, however it seems that SSH bleeds out the colour.

SSHD Look:

enter image description here

Output when running the script once logged in:

enter image description here

Actual script:

cat /etc/update-motd.d/20-logo 
#! /usr/bin/env bash
echo "";
echo "$(tput setaf 2)    .::::::::::::::::::::::::::::::::::::::::...
   :::::::::::::::::::::::::::::::::::::::::::::::::::.
   .::::::::::::::::::::::::::::::::::::::::::::::::::::::.
                                      .....::::::::::::::::::
                  $(tput setaf 7):@@@@@O                          $(tput setaf 2).:::::::::::
                  $(tput setaf 7)@@@@@@@o                             $(tput setaf 2).::::::::
                  $(tput setaf 7)@@@@@@@o                                $(tput setaf 2):::::::
                  $(tput setaf 7)@@@@@@@o                                $(tput setaf 2).::::::
        $(tput setaf 7):@@@@@O   @@@@@@@o   O@@@@O                       $(tput setaf 2):::::::
      $(tput setaf 7):@@@@@@@@o  @@@@@@@o  o@@@@@@@O                    $(tput setaf 2):::::::.
     $(tput setaf 7)o@@@@@@@@O   @@@@@@@o  :@@@@@@@@@                $(tput setaf 2).::::::::.
    $(tput setaf 7)o@@@@@@@O     @@@@@@@o    o@@@@@@@O        $(tput setaf 2)..:::::::::::::
    $(tput setaf 7)@@@@@@@O      @@@@@@@o     :@@@@@@@o  $(tput setaf 2)::::::::::::::::::
   $(tput setaf 7)o@@@@@@@       @@@@@@@:      o@@@@@@@ $(tput setaf 2)::::::::::::::::.
   $(tput setaf 7)o@@@@@@o        o@@@O:        @@@@@@@ $(tput setaf 2).:::::::::..
   $(tput setaf 7)o@@@@@@@                     o@@@@@@@   $(tput setaf 2).:::::::::
   $(tput setaf 7)o@@@@@@@                     O@@@@@@O     $(tput setaf 2).:::::::::.
    $(tput setaf 7)@@@@@@@@                   O@@@@@@@:       $(tput setaf 2).::::::::::.
     $(tput setaf 7)@@@@@@@@O               :@@@@@@@@o           $(tput setaf 2).:::::::::::.
      $(tput setaf 7)@@@@@@@@@O:          o@@@@@@@@@o               $(tput setaf 2)::::::::::::::.
       $(tput setaf 7)O@@@@@@@@@@@@@@@@@@@@@@@@@@@@:                   $(tput setaf 2).:::::::::::::::..
         $(tput setaf 7)O@@@@@@@@@@@@@@@@@@@@@@@@:                         $(tput setaf 2).:::::::::::::::.
           $(tput setaf 7):@@@@@@@@@@@@@@@@@@@O                                $(tput setaf 2).::::::::::::
               $(tput setaf 7)oO@@@@@@@@@@o:                                        $(tput setaf 2)..::::.$(tput sgr0)
";
echo "================================================================================";

I’ve ensured that force_color_prompt=yes is enabled in ~/.bashrc and that my $TERM variable looks right on both sides. Both terminal-emulator and server show xterm-256color

What could be causing the colour to fail on SSH login?


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#StackBounty: #ssh #security #iptables sshguard – must a user declare behavior rules?

Bounty: 50

From this answer I understand that sshguard does include a default behavior that should suit most users, at least those with minimal webserver environments, yet it wasn’t clear to me from the documentation and from this article if one must change the defaults or add directives upon them.

Must a user declare behavior rules for sshguard? Isn’t it shipped with a default set of rules (similar to CSF-LFD)?


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#StackBounty: #debian #ubuntu #ssh #security #repository How to prevent Brute force attacks in Debian systems without fail2ban or CSF-L…

Bounty: 50

How to prevent Brute force attacks in Debian systems without fail2ban or CSF-LFD?

The closest and fastest way I know is ConfigServer’s CSF-LFD but it’s not in the repositories and if I’m going to use a utility I would most prefer something in the repositories (it seems I cannot create a Debian/Ubuntu repository for it because of licensing/legal reasons).

Another solution than CSF-LFD is Fail2ban but it seems to me that the Fail2ban configuration requires firm knowledge in IPS software architecture as well as deep knowledge of Perl compatible regex (PCRE), which both I currently lack (I have some basic PCRE knowledge but not as deep as I think one needs for Fail2ban). It doesn’t seem straight forward as CSF-LFD to me.

Thus I wonder if there is a “smoother” way, maybe manually via IP tables, maybe via some utility I could install directly from the Debian/Ubuntu repositories that could prevent BFAs besides the issue of using SSH keys.


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#StackBounty: #ssh #github #gitlab SSH prompt a passphrase for no passphrase keys on Docker GitLab CI

Bounty: 50

With the following Dockerfile:

FROM nexylan/php-dev:7.1-alpine

COPY entrypoint.sh /
RUN chmod u+x /entrypoint.sh
ENTRYPOINT ["/entrypoint.sh"]

WORKDIR /code

CMD ["tail", "-f", "/dev/null"]

(The entrypoint does nothing related to the issue).

The definition on docker-compose:

version: '2'

services:
  data:
    image: alpine
    volumes:
      - .:/code

  console:
    build: docker/php-console
    volumes_from:
      - data
    env_file:
      - .env

And the following commands on Gitlab CI commands:

image: docker

services:
  - docker:dind

before_script:
  - docker info
  - apk add --update bash python py-pip python-dev
  - pip install docker-compose
  - docker-compose up -d
  - docker-compose ps
  - docker-compose exec -T console make install

stages:
  - test

test:
  stage: test
  tags: [docker-privileged]
  script:
    - echo ${SSH_PRIVATE_KEY} > tests/fixtures/ssh/key
    - echo ${SSH_PUBLIC_KEY} > tests/fixtures/ssh/key.pub
    - chmod 600 tests/fixtures/ssh/*
    - docker-compose exec -T console ls -l tests/fixtures/ssh/
    - docker-compose exec -T console chmod 777 /dev/tty
    - docker exec -t flintci_console_1 ssh -o StrictHostKeyChecking=no -i tests/fixtures/ssh/key -T -vvv git@github.com

The SSH command is always prompting for a passphrase with the following log:

OpenSSH_7.2p2-hpn14v4, OpenSSL 1.0.2k  26 Jan 2017
debug1: Reading configuration data /etc/ssh/ssh_config
debug2: resolving "github.com" port 22
debug2: ssh_connect_direct: needpriv 0
debug1: Connecting to github.com [192.30.253.112] port 22.
debug1: Connection established.
debug1: permanently_set_uid: 0/0
debug1: identity file tests/fixtures/ssh/key type 1
debug1: key_load_public: No such file or directory
debug1: identity file tests/fixtures/ssh/key-cert type -1
debug1: Enabling compatibility mode for protocol 2.0
debug1: Local version string SSH-2.0-OpenSSH_7.2p2-hpn14v4
debug1: Remote protocol version 2.0, remote software version libssh_0.7.0
debug1: no match: libssh_0.7.0
debug2: fd 3 setting O_NONBLOCK
debug1: Authenticating to github.com:22 as 'git'
debug3: send packet: type 20
debug1: SSH2_MSG_KEXINIT sent
debug3: receive packet: type 20
debug1: SSH2_MSG_KEXINIT received
debug2: local client KEXINIT proposal
debug2: KEX algorithms: curve25519-sha256@libssh.org,ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,diffie-hellman-group-exchange-sha256,diffie-hellman-group-exchange-sha1,diffie-hellman-group14-sha1,ext-info-c
debug2: host key algorithms: ecdsa-sha2-nistp256-cert-v01@openssh.com,ecdsa-sha2-nistp384-cert-v01@openssh.com,ecdsa-sha2-nistp521-cert-v01@openssh.com,ssh-ed25519-cert-v01@openssh.com,ssh-rsa-cert-v01@openssh.com,ecdsa-sha2-nistp256,ecdsa-sha2-nistp384,ecdsa-sha2-nistp521,ssh-ed25519,rsa-sha2-512,rsa-sha2-256,ssh-rsa
debug2: ciphers ctos: chacha20-poly1305@openssh.com,aes128-ctr,aes192-ctr,aes256-ctr,aes128-gcm@openssh.com,aes256-gcm@openssh.com,aes128-cbc,aes192-cbc,aes256-cbc,3des-cbc
debug2: ciphers stoc: chacha20-poly1305@openssh.com,aes128-ctr,aes192-ctr,aes256-ctr,aes128-gcm@openssh.com,aes256-gcm@openssh.com,aes128-cbc,aes192-cbc,aes256-cbc,3des-cbc
debug2: MACs ctos: umac-64-etm@openssh.com,umac-128-etm@openssh.com,hmac-sha2-256-etm@openssh.com,hmac-sha2-512-etm@openssh.com,hmac-sha1-etm@openssh.com,umac-64@openssh.com,umac-128@openssh.com,hmac-sha2-256,hmac-sha2-512,hmac-sha1
debug2: MACs stoc: umac-64-etm@openssh.com,umac-128-etm@openssh.com,hmac-sha2-256-etm@openssh.com,hmac-sha2-512-etm@openssh.com,hmac-sha1-etm@openssh.com,umac-64@openssh.com,umac-128@openssh.com,hmac-sha2-256,hmac-sha2-512,hmac-sha1
debug2: compression ctos: none,zlib@openssh.com,zlib
debug2: compression stoc: none,zlib@openssh.com,zlib
debug2: languages ctos: 
debug2: languages stoc: 
debug2: first_kex_follows 0 
debug2: reserved 0 
debug2: peer server KEXINIT proposal
debug2: KEX algorithms: curve25519-sha256@libssh.org,ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,diffie-hellman-group-exchange-sha256,diffie-hellman-group14-sha1,diffie-hellman-group1-sha1
debug2: host key algorithms: ssh-dss,ssh-rsa
debug2: ciphers ctos: chacha20-poly1305@openssh.com,aes256-ctr,aes192-ctr,aes128-ctr,aes256-cbc,aes192-cbc,aes128-cbc,blowfish-cbc
debug2: ciphers stoc: chacha20-poly1305@openssh.com,aes256-ctr,aes192-ctr,aes128-ctr,aes256-cbc,aes192-cbc,aes128-cbc,blowfish-cbc
debug2: MACs ctos: hmac-sha2-256,hmac-sha2-512,hmac-sha1
debug2: MACs stoc: hmac-sha2-256,hmac-sha2-512,hmac-sha1
debug2: compression ctos: none,zlib,zlib@openssh.com
debug2: compression stoc: none,zlib,zlib@openssh.com
debug2: languages ctos: 
debug2: languages stoc: 
debug2: first_kex_follows 0 
debug2: reserved 0 
debug1: kex: algorithm: curve25519-sha256@libssh.org
debug1: kex: host key algorithm: ssh-rsa
debug1: kex: server->client cipher: chacha20-poly1305@openssh.com MAC: <implicit> compression: none
debug1: kex: client->server cipher: chacha20-poly1305@openssh.com MAC: <implicit> compression: none
debug3: send packet: type 30
debug1: expecting SSH2_MSG_KEX_ECDH_REPLY
debug3: receive packet: type 31
debug1: Server host key: ssh-rsa SHA256:nThbg6kXUpJWGl7E1IGOCspRomTxdCARLviKw6E5SY8
Warning: Permanently added 'github.com,192.30.253.112' (RSA) to the list of known hosts.
debug3: send packet: type 21
debug2: set_newkeys: mode 1
debug1: rekey after 134217728 blocks
debug1: SSH2_MSG_NEWKEYS sent
debug1: expecting SSH2_MSG_NEWKEYS
debug3: receive packet: type 21
debug2: set_newkeys: mode 0
debug1: rekey after 134217728 blocks
debug1: SSH2_MSG_NEWKEYS received
debug2: key: tests/fixtures/ssh/key (0x55b4bd4e81a0), explicit
debug3: send packet: type 5
debug3: receive packet: type 6
debug2: service_accept: ssh-userauth
debug1: SSH2_MSG_SERVICE_ACCEPT received
debug3: send packet: type 50
debug3: receive packet: type 51
debug1: Authentications that can continue: publickey
debug3: start over, passed a different list publickey
debug3: preferred publickey,keyboard-interactive,password
debug3: authmethod_lookup publickey
debug3: remaining preferred: keyboard-interactive,password
debug3: authmethod_is_enabled publickey
debug1: Next authentication method: publickey
debug1: Offering RSA public key: tests/fixtures/ssh/key
debug3: send_pubkey_test
debug3: send packet: type 50
debug2: we sent a publickey packet, wait for reply
debug3: receive packet: type 60
debug1: Server accepts key: pkalg ssh-rsa blen 279
debug2: input_userauth_pk_ok: fp SHA256:3aoR/R1oBDYb0QucuGCJfBgIWW4DE2P4DjuWwgtQg/k
debug3: sign_and_send_pubkey: RSA SHA256:3aoR/R1oBDYb0QucuGCJfBgIWW4DE2P4DjuWwgtQg/k
Enter passphrase for key 'tests/fixtures/ssh/key':

The key has no passphrase, and the same docker command works well on my local laptop, not on GitLab CI.

What I’m missing?


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