SSH or Secure Shell or Secure Socket Shell, is a network protocol that gives users a secure way to access a computer over an unsecured network.
Default port: 22
22/tcp open ssh syn-ack
nc -vn <IP> 22
This is discovered by default by nmap. But you can also use sslcan or sslyze.
In some versions of OpenSSH you can make a timing attack to enumerate users. You can use a metasploit module in order to exploit this:
msf> use scanner/ssh/ssh_enumusers
If you know some ssh private key that could be used... lets try it. You can use the nmap script:
Or the MSF auxiliary module:
msf> use scanner/ssh/ssh_identify_pubkeys
You should look here in order to search for valid keys for the victim machine.
admin123, password, brocade, fibranne
admin, cisco, enable, hsa, pix, pnadmin, ripeop, root, shelladmin
admin, Admin123, default, password, secur4u, cisco, Cisco, _Cisco, cisco123, C1sco!23, Cisco123, Cisco1234, TANDBERG, change_it, 12345, ipics, pnadmin, diamond, hsadb, c, cc, attack, blender, changeme
root, nsroot, nsmaint, vdiadmin, kvm, cli, admin
C1trix321, nsroot, nsmaint, kaviza, kaviza123, freebsd, public, rootadmin, wanscaler
private, admin, user
root, user1, admin, vkernel, cli
calvin, 123456, password, vkernel, Stor@ge!, admin
admin, root, sysadmin
EMCPMAdm7n, Password#1, Password123#, sysadmin, changeme, emc
admin, root, vcx, app, spvar, manage, hpsupport, opc_op
admin, password, hpinvent, iMC123, pvadmin, passw0rd, besgroup, vcx, nice, access, config, 3V@rpar, 3V#rpar, procurve, badg3r5, OpC_op, !manage, !admin
123456, admin, root, Admin123, Admin@storage, Huawei12#$, HwDec@01, hwosta2.0, HuaWei123, fsp200@HW, huawei123
USERID, admin, manager, mqm, db2inst1, db2fenc1, dausr1, db2admin, iadmin, system, device, ufmcli, customer
PASSW0RD, passw0rd, admin, password, Passw8rd, iadmin, apc, 123456, cust0mer
root, oracle, oravis, applvis, ilom-admin, ilom-operator, nm2user
changeme, ilom-admin, ilom-operator, welcome1, oracle
vi-admin, root, hqadmin, vmware, admin
vmware, vmw@re, hqadmin, default
You can configure SSH to behave as a SFTP server. So, some users will connect to SFTP service (in port 22) instead of to the SSH service.
You can even set a chroot to the SFTP users. A configuration example of SFTP users inside the file /etc/ssh/sshd_config can be seen in the following images.
All the ots-* users will be jailed inside a chroot.
If you have access to a SFTP server you can also tunnel your traffic through this for example using the common port forwarding:
sudo ssh -L <local_port>:<remote_host>:<remote_port> -N -f <username>@<ip_compromised>
The sftp have the command "symlink". Therefor, if you have writable rights in some folder, you can create symlinks of other folders/files. As you are probably trapped inside a chroot this won't be specially useful for you, but, if you can access the created symlink from a no-chroot service (for example, if you can access the symlink from the web), you could open the symlinked files through the web.
For example, to create a symlink from a new file "froot" to "/":
sftp> symlink / froot
If you can access the file "froot" via web, you will be able to list the root ("/") folder of the system.