De vez en cuando, mi servidor de correo deja de enviar correos nuevos y cada vez que encuentro el registro de errores,
Jun 22 23:10:18 myserver saslauthd[3967]: DEBUG: auth_pam: pam_authenticate failed: Memory buffer error
Jun 22 23:10:18 myserver saslauthd[3971]: DEBUG: auth_pam: pam_authenticate failed: Memory buffer error
Jun 22 23:10:19 myserver saslauthd[3972]: DEBUG: auth_pam: pam_authenticate failed: Memory buffer error
Jun 22 23:10:19 myserver saslauthd[3968]: DEBUG: auth_pam: pam_authenticate failed: Memory buffer error
Jun 22 23:10:20 myserver saslauthd[3969]: DEBUG: auth_pam: pam_authenticate failed: Memory buffer error
Jun 22 23:10:20 myserver saslauthd[3967]: DEBUG: auth_pam: pam_authenticate failed: Memory buffer error
Jun 22 23:10:21 myserver saslauthd[3971]: DEBUG: auth_pam: pam_authenticate failed: Memory buffer error
Jun 22 23:10:21 myserver saslauthd[3972]: DEBUG: auth_pam: pam_authenticate failed: Memory buffer error
Jun 22 23:10:22 myserver saslauthd[3971]: DEBUG: auth_pam: pam_authenticate failed: Memory buffer error
Cada vez que tengo que reiniciar mi servidor para que vuelva a funcionar normalmente
También siempre encuentro el siguiente registro de errores repetitivos de IP desconocidas (no estoy seguro si está relacionado o no):
Jun 21 06:48:43 myserver sshd[1687]: PAM 2 more authentication failures; logname= uid=0 euid=0 tty=ssh ruser= rhost=************ user=root
Jun 21 06:48:45 myserver sshd[1708]: Failed password for root from ######## port 60021 ssh2
Jun 21 06:48:47 myserver sshd[1708]: Failed password for root from ######## port 60021 ssh2
Jun 21 06:48:47 myserver sshd[1708]: Received disconnect from #######: 11: [preauth]
Jun 21 06:48:47 myserver sshd[1708]: PAM 2 more authentication failures; logname= uid=0 euid=0 tty=ssh ruser= rhost=************ user=root
Jun 21 06:48:47 myserver sshd[1730]: pam_unix(sshd:auth): authentication failure; logname= uid=0 euid=0 tty=ssh ruser= rhost=************ user=root
Jun 21 06:48:48 myserver sshd[1732]: pam_unix(sshd:auth): authentication failure; logname= uid=0 euid=0 tty=ssh ruser= rhost============= user=root
Jun 21 06:48:48 myserver sshd[1730]: Failed password for root from ************ port 60094 ssh2
Jun 21 06:48:50 myserver sshd[1732]: Failed password for root from ============ port 40613 ssh2
Jun 21 06:48:50 myserver sshd[1730]: Failed password for root from ************ port 60094 ssh2
Jun 21 06:48:50 myserver sshd[1734]: pam_unix(sshd:auth): authentication failure; logname= uid=0 euid=0 tty=ssh ruser= rhost=************ user=root
Jun 21 06:48:52 myserver sshd[1736]: pam_unix(sshd:auth): authentication failure; logname= uid=0 euid=0 tty=ssh ruser= rhost=************ user=root
Jun 21 06:48:52 myserver sshd[1732]: Failed password for root from ============ port 40613 ssh2
Jun 21 06:48:52 myserver sshd[1730]: Failed password for root from ************ port 60094 ssh2
Jun 21 06:48:52 myserver sshd[1730]: Received disconnect from ***********: 11: [preauth]
Jun 21 06:48:52 myserver sshd[1730]: PAM 2 more authentication failures; logname= uid=0 euid=0 tty=ssh ruser= rhost=*********** user=root
Jun 21 06:48:52 myserver sshd[1734]: Failed password for root from ######## port 47803 ssh2
Jun 21 06:48:54 myserver sshd[1736]: Failed password for root from ######## port 55371 ssh2
Jun 21 06:48:54 myserver sshd[1732]: Failed password for root from ============ port 40613 ssh2
Respuesta1
De acuerdo ahttps://bugs.debian.org/cgi-bin/bugreport.cgi?bug=758660 saslauthd deja de funcionar después de una cierta cantidad de inicios de sesión (exitosos y/o fallidos).
No es necesario reiniciar todo el servidor, lo siguiente es suficiente:service saslauthd restart
Puedes poner eso en un crontab. Si muchos inicios de sesión se originan desde la misma IP maliciosa, puede eliminar la solicitud de esa IP en el firewall para que saslauthd dure más, por ejemploiptables -A INPUT -s 185.29.11.6 -j DROP