Disable Fedora Cockpit
Quick and dirty:
service cockpit stop service cockpit.socket stop systemctl disable cockpit systemctl disable cockpit.socket systemctl mask cockpit.socket systemctl mask cockpit
sshd without-password vs prohibit-password
Upgrading a server from Debian 8 to Debian 9 - I noticed in /etc/ssh/sshd_config that ‘PermitRootLogin’ had the argument ‘prohibit-password’. Having not seen that before I wondered what the difference was between that and ‘without-password’.
Turns out that mean and do the same thing - but ‘prohibit-password’ was introduced to be less ambigous. So there you have it!
Check out the release notes here for proof :-)
Add comments to IPTables firewall rules
Instead of just documenting the IPTables configuration file eg: /etc/sysconfig/iptables with comments (#’s) you can also input comments as part of the ruleset itself. So when you perform iptables -L -v -n you get the following output:
root@server070:[~]: iptables -L -v -n Chain INPUT (policy ACCEPT 0 packets, 0 bytes) pkts bytes target prot opt in out source destination 64M 4727M ACCEPT all -- * * 0.0.0.0/0 0.0.0.0/0 state RELATED,ESTABLISHED 5 474 ACCEPT icmp -- * * 0.0.0.0/0 0.0.0.0/0 202K 27M ACCEPT all -- lo * 0.0.0.0/0 0.0.0.0/0 16 880 ACCEPT tcp -- * * 0.0.0.0/0 0.0.0.0/0 state NEW tcp dpt:22 137M 38G ACCEPT udp -- * * 0.0.0.0/0 0.0.0.0/0 udp dpt:514 /* Syslog traffic */ 28 1664 ACCEPT tcp -- * * 0.0.0.0/0 0.0.0.0/0 tcp dpt:514 /* Syslog traffic */ 41067 2050K ACCEPT tcp -- * * 0.0.0.0/0 0.0.0.0/0 tcp dpt:9997 /* Universal Forwarder traffic */ 0 0 ACCEPT tcp -- * * 0.0.0.0/0 0.0.0.0/0 tcp dpt:8089 /* Splunk SSL traffic */ 47 2564 ACCEPT tcp -- * * 0.0.0.0/0 0.0.0.0/0 tcp dpt:8000 /* Splunk web interface */ 14135 1313K LOG all -- * * 0.0.0.0/0 0.0.0.0/0 limit: avg 5/min burst 5 LOG flags 0 level 7 prefix `iptables denied: ' 218K 21M REJECT all -- * * 0.0.0.0/0 0.0.0.0/0 reject-with icmp-host-prohibited
All that you need to do use the following example in your configuration file:
root@server070:[~]: cat /etc/sysconfig/iptables *filter :INPUT ACCEPT [0:0] :FORWARD ACCEPT [0:0] :OUTPUT ACCEPT [0:0] -A INPUT -m state --state RELATED,ESTABLISHED -j ACCEPT -A INPUT -p icmp -j ACCEPT -A INPUT -i lo -j ACCEPT -A INPUT -p tcp -m state --state NEW -m tcp --dport 22 -j ACCEPT -A INPUT -p udp -m udp --dport 514 -m comment --comment "Syslog traffic" -j ACCEPT -A INPUT -p tcp -m tcp --dport 514 -m comment --comment "Syslog traffic" -j ACCEPT -A INPUT -p tcp -m tcp --dport 9997 -m comment --comment "Universal Forwarder traffic" -j ACCEPT -A INPUT -p tcp -m tcp --dport 8089 -m comment --comment "Splunk SSL traffic" -j ACCEPT -A INPUT -p tcp -m tcp --dport 8000 -m comment --comment "Splunk web interface" -j ACCEPT -A INPUT -m limit --limit 5/min -j LOG --log-prefix "iptables denied: " --log-level 7 -A INPUT -j REJECT --reject-with icmp-host-prohibited -A FORWARD -j REJECT --reject-with icmp-host-prohibited COMMIT
Happy commenting!
Fedora 23 RPM package for ‘mutt-sidebar’
Finally someone has created an RPM for Fedora 23 so that I can use mutt-sidebar!
Details are here: https://copr.fedorap … /cam34/mutt-sidebar/
How to block malicious VBA documents and spreadsheets with spam assassin or amavisd
Monitoring our net streams for SMTP traffic, I have a particular Splunk alert configured to alert when a spam campaign in underway. It’s quite interesting to see what tricks spammers try and how long some campaigns last.
Something that has caught my attention is the increased use of unsolicited “invoice” and “order” emails which get sent with .doc documents attached. Reviewing the documents nearly all of them contain malicious VB scripting usually set to auto run, which downloads and tries to execute binaries.
Now I have created a number of spam assassin rules to block these types of emails (invoices with .doc files attached) but it’s a cat and mouse game, and you can’t be too generic as you may block legitimate email. What I can block ruthlessly is documents and spreadsheets which contain autorun VB scripting.
Here is how to do it:
Create the following file on your amavisd server at the location “/usr/local/bin/detectvba.pl”
#!/usr/bin/perl -w # technion@lolware.net # Detects vba macros containing blacklisted strings. # https://github.com/technion/maia_mailguard/blob/master/scripts/detectvba.pl # Mods by www.cammckenzie.com # # Suggested amavisd/maiad.conf config: # ['Detect-VBA', # '/usr/local/bin/detectvba.pl', "{}", # [0], qr/INFECTED/, qr/\bINFECTED (.+)\b/m ], # use strict; my $sigtool = '/usr/bin/sigtool'; #Clamav sigtool path if ($#ARGV != 0) { print "Please supply directory to scan\n"; exit 0; } #Sanity check directory my $dir = $ARGV[0]; if ($dir !~ /^[a-z0-9A-Z\/-]+$/) { print "Invalid directory passed\n"; exit 0; } opendir DIR, $dir or die "Cannot open dir $dir: $!"; my @files = readdir DIR; foreach my $file (@files) { next if $file =~ /^\.$/; next if $file =~ /^\.\.$/; my $scan = `$sigtool --vba="$dir/$file"`; if ($scan =~ /autoopen/i ) { print "Scanning $file: INFECTED VBA\n"; exit 1; } else { print "Scanning $file: OK\n"; } } closedir DIR; exit 0;
Then in amavisd.conf (/etc/amavisd/amavisd.conf on CentOS) modify the section “@av_scanners” and insert as a primary scanner the following stanza:
['Detect-VBA', '/usr/loca/bin/detectvba.pl', "{}", [0], qr/INFECTED/, qr/\bINFECTED (.+)\b/m ],
Then after that just restart your amavisd service and you should see, it finds Detect-VBA as a primary scanner, test it by sending yourself a malicious macro document lol.
Download the raw howto here, so that special characters are intact as FlatPress has a habit of removing them….https://www.cammcken … assin-or-amavisd.txt