Tutaj poniżej pokażę Ci prosty przykład, jak może wyglądać połączenie ssh do serwera:Witam.
Ostatnio przeskanowałem sobie Debiana nmapem i w wynikach otrzymałem między innymi coś takiego:Kod: Zaznacz cały
7532/tcp open ssh OpenSSH 5.1p1 Debian 5 (protocol 2.0) | ssh-hostkey: 1024 58:30:41:09:93:cd:a0:54:a4:xx:xx:xx:xx:xx:xx:xx (DSA) |_2048 34:d0:f1:02:99:17:1b:47:51:xx:xx:xx:xx:xx:xx:xx (RSA)
- Zastanawiam się, czy przypadkiem mój Debian nie chwali się zbyt dużą ilością informacji?
- Dodatkowo mam pytanie czy te informację mogą w jakiś sposób ułatwić robotę potencjalnemu hakerowi?
- No i na koniec jak ograniczyć/wyłączyć wyświetlanie tych informacji? Jak się zabezpieczyć?
- Połączenie podstawowe, jakie wiele osób wykonuje:
Kod: Zaznacz cały
adasiek@sea-star:~$ ssh -l root -C 192.168.6.254Kod: Zaznacz cały
Last login: Fri May 20 09:04:17 2011 from 192.168.6.164 Have a lot of fun... serek-hurt:~ # - Teraz drobna zmiana polecenia:
Kod: Zaznacz cały
adasiek@sea-star:~$ ssh -l root -C 192.168.6.254 -vKod: Zaznacz cały
OpenSSH_5.5p1 Debian-4ubuntu5, OpenSSL 0.9.8o 01 Jun 2010 debug1: Reading configuration data /home/adasiek/.ssh/config debug1: Applying options for * debug1: Reading configuration data /etc/ssh/ssh_config debug1: Applying options for * debug1: Connecting to 192.168.6.254 [192.168.6.254] port 22. debug1: Connection established. debug1: identity file /home/adasiek/.ssh/id_rsa type 1 debug1: Checking blacklist file /usr/share/ssh/blacklist.RSA-1024 debug1: Checking blacklist file /etc/ssh/blacklist.RSA-1024 debug1: identity file /home/adasiek/.ssh/id_rsa-cert type -1 debug1: identity file /home/adasiek/.ssh/id_dsa type -1 debug1: identity file /home/adasiek/.ssh/id_dsa-cert type -1 debug1: Remote protocol version 1.99, remote software version OpenSSH_4.1 debug1: match: OpenSSH_4.1 pat OpenSSH_4* debug1: Enabling compatibility mode for protocol 2.0 debug1: Local version string SSH-2.0-OpenSSH_5.5p1 Debian-4ubuntu5 debug1: SSH2_MSG_KEXINIT sent debug1: SSH2_MSG_KEXINIT received debug1: kex: server->client aes128-ctr hmac-md5 zlib debug1: kex: client->server aes128-ctr hmac-md5 zlib debug1: SSH2_MSG_KEX_DH_GEX_REQUEST(1024<1024<8192) sent debug1: expecting SSH2_MSG_KEX_DH_GEX_GROUP debug1: SSH2_MSG_KEX_DH_GEX_INIT sent debug1: expecting SSH2_MSG_KEX_DH_GEX_REPLY debug1: Host '192.168.6.254' is known and matches the RSA host key. debug1: Found key in /home/adasiek/.ssh/known_hosts:75 debug1: ssh_rsa_verify: signature correct debug1: Enabling compression at level 6. debug1: SSH2_MSG_NEWKEYS sent debug1: expecting SSH2_MSG_NEWKEYS debug1: SSH2_MSG_NEWKEYS received debug1: Roaming not allowed by server debug1: SSH2_MSG_SERVICE_REQUEST sent debug1: SSH2_MSG_SERVICE_ACCEPT received debug1: Authentications that can continue: publickey,keyboard-interactive debug1: Next authentication method: publickey debug1: Offering public key: /home/adasiek/.ssh/id_rsa debug1: Server accepts key: pkalg ssh-rsa blen 149 debug1: read PEM private key done: type RSA debug1: Authentication succeeded (publickey). debug1: channel 0: new [client-session] debug1: Entering interactive session. debug1: Sending environment. debug1: Sending env LANG = pl_PL.utf8 Last login: Fri May 20 09:04:26 2011 from 192.168.6.164 Have a lot of fun... serek-hurt:~ # serek-hurt:~ # logout debug1: client_input_channel_req: channel 0 rtype exit-status reply 0 debug1: channel 0: free: client-session, nchannels 1 Connection to 192.168.6.254 closed. Transferred: sent 1912, received 1960 bytes, in 61.9 seconds Bytes per second: sent 30.9, received 31.7 debug1: Exit status 1 debug1: compress outgoing: raw data 1067, compressed 659, factor 0.62 debug1: compress incoming: raw data 492, compressed 421, factor 0.86 adasiek@sea-star:~$ - I jeszcze kolejna modyfikacja polecenia:
Kod: Zaznacz cały
adasiek@sea-star:~$ ssh -l root -C 192.168.6.254 -vvKod: Zaznacz cały
OpenSSH_5.5p1 Debian-4ubuntu5, OpenSSL 0.9.8o 01 Jun 2010 debug1: Reading configuration data /home/adasiek/.ssh/config debug1: Applying options for * debug1: Reading configuration data /etc/ssh/ssh_config debug1: Applying options for * debug2: ssh_connect: needpriv 0 debug1: Connecting to 192.168.6.254 [192.168.6.254] port 22. debug1: Connection established. debug2: key_type_from_name: unknown key type '-----BEGIN' debug2: key_type_from_name: unknown key type '-----END' debug1: identity file /home/adasiek/.ssh/id_rsa type 1 debug1: Checking blacklist file /usr/share/ssh/blacklist.RSA-1024 debug1: Checking blacklist file /etc/ssh/blacklist.RSA-1024 debug1: identity file /home/adasiek/.ssh/id_rsa-cert type -1 debug1: identity file /home/adasiek/.ssh/id_dsa type -1 debug1: identity file /home/adasiek/.ssh/id_dsa-cert type -1 debug1: Remote protocol version 1.99, remote software version OpenSSH_4.1 debug1: match: OpenSSH_4.1 pat OpenSSH_4* debug1: Enabling compatibility mode for protocol 2.0 debug1: Local version string SSH-2.0-OpenSSH_5.5p1 Debian-4ubuntu5 debug2: fd 3 setting O_NONBLOCK debug1: SSH2_MSG_KEXINIT sent debug1: SSH2_MSG_KEXINIT received debug2: kex_parse_kexinit: diffie-hellman-group-exchange-sha256,diffie-hellman-group-exchange-sha1,diffie-hellman-group14-sha1,diffie-hellman-group1-sha1 debug2: kex_parse_kexinit: [email protected],[email protected],ssh-rsa,ssh-dss debug2: kex_parse_kexinit: aes128-ctr,aes192-ctr,aes256-ctr,arcfour256,arcfour128,aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,aes192-cbc,aes256-cbc,arcfour,[email protected] debug2: kex_parse_kexinit: aes128-ctr,aes192-ctr,aes256-ctr,arcfour256,arcfour128,aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,aes192-cbc,aes256-cbc,arcfour,[email protected] debug2: kex_parse_kexinit: hmac-md5,hmac-sha1,[email protected],hmac-ripemd160,[email protected],hmac-sha1-96,hmac-md5-96 debug2: kex_parse_kexinit: hmac-md5,hmac-sha1,[email protected],hmac-ripemd160,[email protected],hmac-sha1-96,hmac-md5-96 debug2: kex_parse_kexinit: [email protected],zlib,none debug2: kex_parse_kexinit: [email protected],zlib,none debug2: kex_parse_kexinit: debug2: kex_parse_kexinit: debug2: kex_parse_kexinit: first_kex_follows 0 debug2: kex_parse_kexinit: reserved 0 debug2: kex_parse_kexinit: diffie-hellman-group-exchange-sha1,diffie-hellman-group14-sha1,diffie-hellman-group1-sha1 debug2: kex_parse_kexinit: ssh-rsa,ssh-dss debug2: kex_parse_kexinit: aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,arcfour,aes192-cbc,aes256-cbc,[email protected],aes128-ctr,aes192-ctr,aes256-ctr debug2: kex_parse_kexinit: aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,arcfour,aes192-cbc,aes256-cbc,[email protected],aes128-ctr,aes192-ctr,aes256-ctr debug2: kex_parse_kexinit: hmac-md5,hmac-sha1,hmac-ripemd160,[email protected],hmac-sha1-96,hmac-md5-96 debug2: kex_parse_kexinit: hmac-md5,hmac-sha1,hmac-ripemd160,[email protected],hmac-sha1-96,hmac-md5-96 debug2: kex_parse_kexinit: none,zlib debug2: kex_parse_kexinit: none,zlib debug2: kex_parse_kexinit: debug2: kex_parse_kexinit: debug2: kex_parse_kexinit: first_kex_follows 0 debug2: kex_parse_kexinit: reserved 0 debug2: mac_setup: found hmac-md5 debug1: kex: server->client aes128-ctr hmac-md5 zlib debug2: mac_setup: found hmac-md5 debug1: kex: client->server aes128-ctr hmac-md5 zlib debug1: SSH2_MSG_KEX_DH_GEX_REQUEST(1024<1024<8192) sent debug1: expecting SSH2_MSG_KEX_DH_GEX_GROUP debug2: dh_gen_key: priv key bits set: 123/256 debug2: bits set: 504/1024 debug1: SSH2_MSG_KEX_DH_GEX_INIT sent debug1: expecting SSH2_MSG_KEX_DH_GEX_REPLY debug1: Host '192.168.6.254' is known and matches the RSA host key. debug1: Found key in /home/adasiek/.ssh/known_hosts:75 debug2: bits set: 540/1024 debug1: ssh_rsa_verify: signature correct debug2: kex_derive_keys debug2: set_newkeys: mode 1 debug1: Enabling compression at level 6. debug1: SSH2_MSG_NEWKEYS sent debug1: expecting SSH2_MSG_NEWKEYS debug2: set_newkeys: mode 0 debug1: SSH2_MSG_NEWKEYS received debug1: Roaming not allowed by server debug1: SSH2_MSG_SERVICE_REQUEST sent debug2: service_accept: ssh-userauth debug1: SSH2_MSG_SERVICE_ACCEPT received debug2: key: /home/adasiek/.ssh/id_rsa (0x7f2eed3ad0f0) debug2: key: /home/adasiek/.ssh/id_dsa ((nil)) debug1: Authentications that can continue: publickey,keyboard-interactive debug1: Next authentication method: publickey debug1: Offering public key: /home/adasiek/.ssh/id_rsa debug2: we sent a publickey packet, wait for reply debug1: Server accepts key: pkalg ssh-rsa blen 149 debug2: input_userauth_pk_ok: fp 07:f1:73:35:27:b4:3e:c4:a8:cb:f1:9b:bc:f5:10:a1 debug1: read PEM private key done: type RSA debug1: Authentication succeeded (publickey). debug1: channel 0: new [client-session] debug2: channel 0: send open debug1: Entering interactive session. debug2: callback start debug2: client_session2_setup: id 0 debug2: channel 0: request pty-req confirm 1 debug1: Sending environment. debug1: Sending env LANG = pl_PL.utf8 debug2: channel 0: request env confirm 0 debug2: channel 0: request shell confirm 1 debug2: fd 3 setting TCP_NODELAY debug2: callback done debug2: channel 0: open confirm rwindow 0 rmax 32768 debug2: channel_input_status_confirm: type 99 id 0 debug2: PTY allocation request accepted on channel 0 debug2: channel 0: rcvd adjust 131072 debug2: channel_input_status_confirm: type 99 id 0 debug2: shell request accepted on channel 0 Last login: Fri May 20 09:06:10 2011 from 192.168.6.164 Have a lot of fun... serek-hurt:~ # logout 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: client_input_channel_req: channel 0 rtype exit-status reply 0 debug2: channel 0: rcvd close debug2: channel 0: close_read debug2: channel 0: input open -> closed debug2: channel 0: almost dead debug2: channel 0: gc: notify user debug2: channel 0: gc: user detached debug2: channel 0: send close debug2: channel 0: is dead debug2: channel 0: garbage collecting debug1: channel 0: free: client-session, nchannels 1 Connection to 192.168.6.254 closed. Transferred: sent 1848, received 1848 bytes, in 1.7 seconds Bytes per second: sent 1095.0, received 1095.0 debug1: Exit status 0 debug1: compress outgoing: raw data 1033, compressed 640, factor 0.62 debug1: compress incoming: raw data 420, compressed 388, factor 0.92 adasiek@sea-star:~$
Pozdrawiam,
Adam
temat nie wnosi niczego . powinien być skasowany.