November 2020

A different lens of sorts

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Especially in big companies where these monoliths spanned more than a team’s cognitive horizon, violations of those boundaries were often a simple import away, and of course rife.

Source: Microservices — architecture nihilism in minimalism’s clothes – Blog by Vasco Figueira

Most of this is way, way over my head but I’m now introduced to the concept of “cognitive horizon”, which applies to more than IT. It describes perfectly what’s happening when I’m expediting in a restaurant.

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Migración de alto calibre

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NOGALES, Mexico — North of the border, the .50-caliber sniper rifle is the stuff of YouTube celebrity, shown blasting through engine blocks and concrete walls. Deployed with U.S. troops to foreign wars, it is among the most destructive weapons legally available in the United States.But every week, those rifles are trafficked across the border to Mexico, where increasingly militarized drug cartels now command arsenals that rival the weaponry of the country’s security forces. In many cases, criminals outgun police.

Source: Mexico guns: Sniper rifles are flowing to Mexican drug cartels from the U.S. – Washington Post

Los carteles todavía no se animan a realizar asesinatos tácticos de una bala, prefiriendo mostrar sus poderío enviando comandos armados.

Pero para allá van.

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Storage

/ flickr
        <a href="https://www.flickr.com/people/nullrend/">nullrend</a> posted a photo:

Storage

Forefront are five HP 36 GB 10K SAS hard disk drives, next to five Micron 5200 PRO solid state drives.

It’s both amazing and ridiculous how quickly technology evolves.

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Accessorize your Windows toys with WSL

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Normally I would consider this a bug. However over the years I’ve come to the conclusion that Windows is a pretty toy. It works wonderfully “in the small”. But it isn’t useful for significant programmer workloads (like typing :-) ).

Source: WSL Isn’t Linux | Hacker News

Your mistake was considering Windows suitable for anything but media consumption. It will phone home, it will reboot when it feels like it, and it won’t resume state when it does reboot or resume from sleep.

The best use for WSL is to use it to shell into a proper Linux host. Only way you can guarantee you won’t lose your work when the OS decides to do something.

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The Third Surge Is Breaking Health-Care Workers – The Atlantic

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With only lax policies in place, those cases will continue to rise. Hospitalizations lag behind cases by about two weeks; by Thanksgiving, today’s soaring cases will be overwhelming hospitals that already cannot cope. “The wave hasn’t even crashed down on us yet,” Perencevich said. “It keeps rising and rising, and we’re all running on fear. The health-care system in Iowa is going to collapse, no question.”

Source: The Third Surge Is Breaking Health-Care Workers – The Atlantic

The scene on Interstellar when our protagonists realize those aren’t mountains.

They’re waves. The next one is cresting over the US right now and we’re just here for the ride.

A lot of people are not going to make it

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Block attacker IP addresses, four ways

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If you run WordPress you’ve seen these in your web server logs:

132.232.46.230 - - [29/Oct/2020:13:58:41 -0500] "POST /xmlrpc.php HTTP/1.1" 200 259 "-" "Apache-HttpClient/4.5.2 (Java/1.8.0_151)" "-"
132.232.46.230 - - [29/Oct/2020:13:58:44 -0500] "POST /xmlrpc.php HTTP/1.1" 200 259 "-" "Apache-HttpClient/4.5.2 (Java/1.8.0_151)" "-"
132.232.46.230 - - [29/Oct/2020:13:58:48 -0500] "POST /xmlrpc.php HTTP/1.1" 200 259 "-" "Apache-HttpClient/4.5.2 (Java/1.8.0_151)" "-"
132.232.46.230 - - [29/Oct/2020:13:58:52 -0500] "POST /xmlrpc.php HTTP/1.1" 200 259 "-" "Apache-HttpClient/4.5.2 (Java/1.8.0_151)" "-"
132.232.46.230 - - [29/Oct/2020:13:58:55 -0500] "POST /xmlrpc.php HTTP/1.1" 200 259 "-" "Apache-HttpClient/4.5.2 (Java/1.8.0_151)" "-"
132.232.46.230 - - [29/Oct/2020:13:58:58 -0500] "POST /xmlrpc.php HTTP/1.1" 200 259 "-" "Apache-HttpClient/4.5.2 (Java/1.8.0_151)" "-"

Fucken scanners just slamming xmlrpc.php looking for a way in. When this happens CPU usage just goes through the roof for as long as the scan lasts and it could be five minutes, could be six hours, could be all week; before it ends. The gods help you if you’re paying by CPU usage.

So you have to block access to the file. You could just block all access to XML-RPC but doing this will prevent the WP mobile app from working.

We’ll just block that specific IP address but we need to be quick about it; just do a quick one liner on the terminal before the OS just topples over and becomes completely unresponsive or worse.

iptables

This should work for any Linux distribution that has iptables out of the box which is basically all of them.

# iptables -I INPUT -s 132.232.46.230 -j DROP
  • -I: Insert the rule as the first rule to be applied in the INPUT chain. You could use -A (append) but the sooner we get rid of that traffic the less work the CPU has to do.
  • -s: Source address, in this case 132.232.46.230, which belongs to Tencent.
  • -j: jump to the DROP target. If you use the REJECT target you’re just creating more work for the CPU.

Documentation here but the Ubuntu how-to is far more useful in getting people started.

pf

As it is part of both FreeBSD and OpenBSD base installations it should be enabled in /etc/rc.conf but from reading the (almost useless) documentation and looking around the web You need to fuck around with pf.conf first, then you can manipulate the table. This is the first result on the web when you search for “pf block ip address”. So no one-liner that can save your life.

Edit /etc/pf.conf and add

table <badhosts> persist
block on fxp0 from <badhosts> to any
  • Create table named badhosts, and set it to be persistent in kernel memory
  • Block, on interface fxp0 (you’ll want to change this), traffic from rules in the badhosts table to any destination.

Once you have this you can manipulate the table from the command line with pfctl

# pfctl -t badhosts -T add 132.232.46.230
  • -t means pfctl will manipulate the badhosts table
  • -T will show statistics
  • add address 132.232.46.230 to the table

Fucken hell FreeBSD documentation is the fucken worst. Dryer than Melania Trump’s libido. Now, reading through the OpenBSD pf documentation it looks like you can do

# pfctl -t badhosts -T add 203.0.113.0/24

Which will create the badhosts table automatically without having to fuck around with /etc/pf.conf. Don’t know if this will work on FreeBSD though.

ipfw

It is part of the FreeBSD base installation so it does depend on ipfw being enabled in /etc/rc.conf but it looks like you can go

# ipfw add deny all from 132.232.46.230 to any
  • Add rule denying any and all fraffic from 132.232.46.230 to any destination

At least these rules are succint and easy to read. Whomever wrote the documentation seemed to pay more attention to usage at least.

Still, fuck FreeBSD.

Windows

Super easy now that PowerShell is built into Windows itself:

PS C:\WINDOWS\system32> New-NetFirewallRule -DisplayName "Block traffic from 132.232.46.230" -Direction Inbound -LocalPort Any -Protocol Any - Action Block -RemoteAddress 132.232.46.230
  • -DisplayName: The human-readable name of the firewall rule
  • -Direction: Can be Outbound or Inbound. We want Inbound obviously.
  • -LocalPort: Going with any ports because fuck crackers.
  • -Protocol: Same, block all port
  • -Action: Block traffic
  • -RemoteAddress: Specifying only 132.232.46.230

The documentation for the commandlet is super nice. No, I’m not typing ‘cmdlet’.

The old way involved so, so manny clicks. PowerShell makes it easy.

Now all of the previous bits of code cease to have any effect after a system reboot so if you want the rules to be permanent… don’t. Blackhats will just scan from different hosts and different networks so blocking an IP address permanently is just unproductive.

A better solution is to use fail2ban:

There is also CrowdSec but I haven’t personally used them.

This post came to be cos I spent 30+ minutes trying to figure out how to block traffic on a FreeBSD host and their documentation is just… inscrutable. Should you ask for help in their forums you’ll just get told to RTFM.

You end up going in circles, consuming yourself in rage and frustration which does not feel nice. Rage-posting is where it’sat.

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