Isso resolveu meu problema semelhante:
apt-get install putty-tools
plink admin@routerip
...
Server version: SSH-2.0-dropbear_0.46
Using SSH protocol version 2
We claim version: SSH-2.0-PuTTY_Local:_Aug_11_2013_21:26:51
Using Diffie-Hellman with standard group "group1"
Doing Diffie-Hellman key exchange with hash SHA-1
Host key fingerprint is:
ssh-rsa 1040 d6:8f:96:ec:73:70:67:33:70:a7:52:a6:8a:2f:56:14
Initialised triple-DES CBC client->server encryption
Initialised HMAC-SHA1 client->server MAC algorithm
Initialised triple-DES CBC server->client encryption
Initialised HMAC-SHA1 server->client MAC algorithm
Using username "admin".
[email protected]'s password: