NeWorld

Kovojame prieš SSH bruteforce

by neworld on Geg.07, 2008, under Administravimas, Sagumas, Serveris

jau ne pirmą dieną loguose pastebiu maždaug tokias eilutes:

May 5 20:51:05 server sshd(pam_unix)[15951]: authentication failure; logname= uid=0 euid=0 tty=ssh ruser= rhost=59-106-25-60.r-bl100.sakura.ne.jp user=root
May 5 20:51:10 server sshd(pam_unix)[15969]: authentication failure; logname= uid=0 euid=0 tty=ssh ruser= rhost=59-106-25-60.r-bl100.sakura.ne.jp user=root
May 5 20:51:15 server sshd(pam_unix)[15989]: authentication failure; logname= uid=0 euid=0 tty=ssh ruser= rhost=59-106-25-60.r-bl100.sakura.ne.jp user=root
May 5 20:51:20 server sshd(pam_unix)[16011]: authentication failure; logname= uid=0 euid=0 tty=ssh ruser= rhost=59-106-25-60.r-bl100.sakura.ne.jp user=root
May 5 20:51:25 server sshd(pam_unix)[16030]: authentication failure; logname= uid=0 euid=0 tty=ssh ruser= rhost=59-106-25-60.r-bl100.sakura.ne.jp user=root
May 5 20:51:29 server sshd(pam_unix)[16050]: authentication failure; logname= uid=0 euid=0 tty=ssh ruser= rhost=59-106-25-60.r-bl100.sakura.ne.jp user=root
May 5 20:51:34 server sshd(pam_unix)[16068]: authentication failure; logname= uid=0 euid=0 tty=ssh ruser= rhost=59-106-25-60.r-bl100.sakura.ne.jp user=root
May 5 20:51:39 server sshd(pam_unix)[16088]: authentication failure; logname= uid=0 euid=0 tty=ssh ruser= rhost=59-106-25-60.r-bl100.sakura.ne.jp user=root
May 5 20:51:44 server sshd(pam_unix)[16144]: authentication failure; logname= uid=0 euid=0 tty=ssh ruser= rhost=59-106-25-60.r-bl100.sakura.ne.jp user=root
May 5 20:51:49 server sshd(pam_unix)[16164]: authentication failure; logname= uid=0 euid=0 tty=ssh ruser= rhost=59-106-25-60.r-bl100.sakura.ne.jp user=root
May 5 20:51:53 server sshd(pam_unix)[16183]: authentication failure; logname= uid=0 euid=0 tty=ssh ruser= rhost=59-106-25-60.r-bl100.sakura.ne.jp user=root
May 5 20:51:58 server sshd(pam_unix)[16199]: authentication failure; logname= uid=0 euid=0 tty=ssh ruser= rhost=59-106-25-60.r-bl100.sakura.ne.jp user=root
May 5 20:52:03 server sshd(pam_unix)[16219]: authentication failure; logname= uid=0 euid=0 tty=ssh ruser= rhost=59-106-25-60.r-bl100.sakura.ne.jp user=root

Vis dedu IP ban, tačiau nepadeda, vis bruteforcina iš kito IP. Taigi ėmiausi kitų metodų, pakeičiau prisijungimo portą (standartinis yra 22), tai daroma paredaguojant /etc/ssh/sshd_config failiuką, reikia susirasti eilutę kur yra port, jeigu jinai užkomentuota, ją atkomentuojame ir parašome neužimto porto skaičių, žinomą tik mums. Tai turėtu maždaug atrodyti taip:

Port 5874

Taigi restartuojame sshd su komanda ‘/etc/init.d/sshd restart’

Tiesa, labai patariu turėti susiinstaliavus webmin, nes gali atsitikti taip kaip man, netyčia nurodžiau užimta portą ir sshd negalėjo pasileisti. Taigi per ssh jau nebegalėjau prisijungti. Liko vienintelė išeitis, per webmin paredaguoti failą ir vėl perkrauti sshd

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