I need to gain a root shell on a linux vm for a security class. I have a user account on the system and a means to write to any file (i.e. /etc...) and want to escalate my privileges with:
I used ssh-keygen to make rsa keys and added them to /root/.ssh/authorized_keys, and modified /etc/ssh/sshd_config to allow root connections. However, I cannot connect to the box as root. This is the output:
Last login: Fri Jan 27 00:43:01 2012 from localhost Connection to localhost closed.
It seems to me that the authentication succeded, however the connection is closed immediately. I have no idea why this isn't working.
The verbose output is:
OpenSSH_4.6p1 Debian-7, OpenSSL 0.9.8g 19 Oct 2007 debug1: Reading configuration data /etc/ssh/ssh_config debug1: Applying options for * debug1: Connecting to localhost [127.0.0.1] port 22. debug1: Connection established. debug1: identity file /home/user/.ssh/identity type -1 debug1: identity file /home/user/.ssh/id_rsa type 1 debug1: identity file /home/user/.ssh/id_dsa type -1 debug1: Remote protocol version 2.0, remote software version OpenSSH_4.6p1 Debian-7 debug1: match: OpenSSH_4.6p1 Debian-7 pat OpenSSH* debug1: Enabling compatibility mode for protocol 2.0 debug1: Local version string SSH-2.0-OpenSSH_4.6p1 Debian-7 debug1: SSH2_MSG_KEXINIT sent debug1: SSH2_MSG_KEXINIT received debug1: kex: server->client aes128-cbc hmac-md5 none debug1: kex: client->server aes128-cbc hmac-md5 none 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 'localhost' is known and matches the RSA host key. debug1: Found key in /etc/ssh/ssh_known_hosts:2 debug1: ssh_rsa_verify: signature correct debug1: SSH2_MSG_NEWKEYS sent debug1: expecting SSH2_MSG_NEWKEYS debug1: SSH2_MSG_NEWKEYS received debug1: SSH2_MSG_SERVICE_REQUEST sent debug1: SSH2_MSG_SERVICE_ACCEPT received debug1: Authentications that can continue: publickey,password,hostbased debug1: Next authentication method: publickey debug1: Trying private key: /home/user/.ssh/identity debug1: Offering public key: /home/user/.ssh/id_rsa debug1: Server accepts key: pkalg ssh-rsa blen 277 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 command: /bin/bash debug1: client_input_channel_req: channel 0 rtype exit-status reply 0 debug1: channel 0: free: client-session, nchannels 1 debug1: Transferred: stdin 0, stdout 0, stderr 0 bytes in 0.0 seconds debug1: Bytes per second: stdin 0.0, stdout 0.0, stderr 0.0 debug1: Exit status 255