docker-ce + Debian Buster + iptables

docker doesn’t work on Debian Buster by default, thanks to nft …

I found docker wouldn’t start for me on my Buster desktop.
journalctl -u docker -f showed :

Aug 15 09:35:50 walnut dockerd[28612]: failed to start daemon: Error initializing network controller: error obtaining controller instance: failed to create NAT chain DOCKER: iptables failed: iptables -t nat -N DOCKER: iptables v1.8.2 (nf_tables):  CHAIN_ADD failed (No such file or 
Aug 15 09:35:50 walnut dockerd[28612]: (exit status 4)

Fixing, yet again, seems a case of replacing nft/nftables stuff with the legacy iptables counterparts –

update-alternatives --set ip6tables /usr/sbin/ip6tables-legacy
update-alternatives --set iptables /usr/sbin/iptables-legacy

Squid 3.4.x for with transparent ssl proxying/support for Debian Wheezy.

I needed  a variant of Squid which supported transparent SSL interception (i.e via iptables redirection) so I could log outgoing HTTPS requests without the client being aware.

The stock wheezy variant doesn’t support SSL (see : Debian Bug Report).

Even after recompiling Wheezy’s squid3 it didn’t seem to work (perhaps my stupidity) so I ended up moving to the latest-and-greatest squid (3.4.9 at the time of writing) and getting that to work. Brief notes follow.

Continue reading “Squid 3.4.x for with transparent ssl proxying/support for Debian Wheezy.”

Fail2ban filter for WordPress

With the annoying brute force wordpress hack going round, one way to protect your site(s) would be to use fail2ban, with a configuration something like (which I’ve shamelessly lifted from http://blog.somsip.com/2011/12/protecting-apache-webservers-from-wordpress-admin-login-dictionary-attacks/ ).

The below seems to be working, and given it’s relative simplicity it’s obvious how you’d go about changing to protect other POST based scripts from brute force attacks.

As with all fail2ban rules, it’s not going to work if the attacker changes IP often (but from scanning the logs so far, it doesn’t seem to be the case that they are).

Obvious caveats :

  1. Users who can’t remember their password(s) will get blocked.
  2. It’s not going to protect you from a distributed attack (multiple IPs) very well
  3. You may want to perform other counter-measures (like putting Apache http authentication in for URLs matching /wp-login.php)

 

In /etc/fail2ban/jail.conf :

[apache-wp-login]
enabled = true
port = http,https
filter = apache-wp-login
logpath = /var/www/vhosts/*/statistics/logs/access_log
maxretry = 5
findtime = 120

And In /etc/fail2ban/filter.d/apache-wp-login.conf :

[Definition]
failregex = <HOST> - - .* "POST /wp-login.php HTTP/.*" 200

ignoreregex =

Where a “hacking” access.log entry looks a bit like :

107.21.107.144 - - [02/Feb/2014:12:50:01 +0000] "POST /wp-login.php HTTP/1.0" 200 4344 "-" "-"