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Koos van den Hout

Koos van den Hout - Latest news, thoughts, rants, projects and other things to write about.
2021-10-13 Wordpress brute force attacks 2 days ago
graph of wordpress https requests showing brute force attack The wordpress blog software is a popular target for attacks. I normally have fail2ban running with some rules to detect bad things on sites behind haproxy but due to some other work on the firewall rules I had that rule disabled.

Someone/something at IP address (A Microsoft-managed IPv4 address) noticed this and fired off a brute force script which ended up making 521525 attempts at logging in, none of which worked.

The first indication of interesting amounts of things happening was that the disc i/o led of the server was blinking a lot. The second indication was the high amount of traffic seen for the specific backend in haproxy.

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2021-10-09 A long bitcoin extortion scam 6 days ago
Cybercriminal This time the scammer / fraud / criminal tries using a lot of text to convince victims to pay bitcoins.

Using bitcoin address bc1qtzqgwqe3cd4cnv26vawxvfg3kr09r0jv53p8nw where it shows this one is already known and no money has been lost.

A bit of a sample, showing that the scammer has some imagination and a good grasp of English:
During the pandemic outbreak a lot of providers have faced difficulties in
maintaining a huge number of staff in their offices and so they have decided to
use outsourcing instead.
While working remotely from home, I have got unlimited abilities to access the
user databases.

I can easily decrypt passwords of users, access their chat history and online
traffic with help of cookie-files.
I have decided to analyse users traffic related to adult websites and adult

My spyware functions as a driver. Hence, I can fully control your device and
have access to your microphone, camera, cursor and set of symbols.
Generally speaking, your device is some sort of my remote PC.
Since this spyware is driver-based, then I can constantly update its
signatures, so that no antivirus can detect it.
While digging through your hard drive, I have saved your entire contact list,
social media access, chat history and media files.
Earlier items about bitcoin extortion scams: Earlier, earlier, earlier, earlier, earlier, earlier, earlier (although I think bitcoin is generally a really bad idea and a huge scam)

Update 2021-10-13: As not enough money is coming into this wallet the scammer tries again. Same address, demanding an amount equivalent to $1150 (USA Dollars). As the mail comes from some random ISP in Chili I think the criminal is somewhere else on this planet.

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2021-10-08 Op het spoor van de scammer/spammer 1 week ago
Cybercriminal Een redelijk standaard valse mail, al bekend bij de fraudehelpdesk: Diverse onderwerpen Klik op “Lees meer” - fraudehelpdesk.nl
   Geachte heer/mevrouw ,
   Er staat een document in uw Berichtenbox van Belastingsamenwerking
   Gemeenten en Waterschappen. Ga naar [1]MijnOverheid om het bericht te
   bekijken. Mogelijk moet u naar aanleiding van dit bericht actie
   ondernemen. Lees het daarom op tijd.
   Met vriendelijke groet,
   Logo Rijksoverheid

   Technisch onderhoud Berichtenbox app
   Vanwege technisch onderhoud is het momenteel niet mogelijk om het
   bericht via de Berichtenbox direct te lezen. Bekijk het bericht daarom
   direct via uw webbrowser.
URL spoor:
  • hxxps://t.co/Fpu3LOuf9Y
  • https://u.nu/SOGTH
  • https://tinee.link/ZJJeb
  • hxxps://ukrijgtterug2020.xyz/
Niet geheel onverwacht is dit domein vandaag geregistreerd:
Registry Domain ID: D253685109-CNIC
Updated Date: 2021-10-08T10:58:04.0Z
Creation Date: 2021-10-08T10:44:42.0Z
Registry Expiry Date: 2022-10-08T23:59:59.0Z
Site staat achter cloudflare IP adressen. Dus het certificaat zegt ook niet zoveel op https://crt.sh/?id=5375183746 en de achterliggende site reageert op dit moment niet dus ik krijg een mooie cloudflare foutmelding.

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2021-10-07 Adding security headers to websites I develop and run 1 week ago
As someone interested in security I'm also busy with securing the websites I develop and run. I'm looking at Content-Security-Policy headers and I notice those seem 'easier' for sites that have one task and one source of development like Camp Wireless and somewhat harder for sites that collect pages/scripts/materials over the years like idefix.net.

Although Camp Wireless can have some advertising, which suddenly turns the whole thing around since advertising scripts can load other advertising scripts completely dynamic. Searching for 'google adwords' and 'Content-Security-Policy' gave me Can Content Security Policy be made compatible with Google Analytics and AdSense? and the answer seems to be either "no" or "with a lot of work which you have to keep updating".

Update: I temporarily added a Content-Security-Policy-Report-Only directive to get an idea what kind of problems I will run into (with my own reporting backend). A lot of them. All inline javascript is suddenly a problem. So a 'fully secured' Content Security Policy header is already hard for single task, single source websites, let alone websites with a lot of history in the pages.

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2021-09-30 Seeing the expiry of the old LetsEncrypt chain happen 2 weeks ago
The 'moment of truth' for LetsEncrypt: the end of the validity of the root certificate that was used to kickstart LetsEncrypt before they got their own root certificate in (most) certificate stores.

I notice openssl is still showing the old chain (but not the expired intermediate):
Certificate chain
 0 s:CN = koos.idefix.net
   i:C = US, O = Let's Encrypt, CN = R3
 1 s:C = US, O = Let's Encrypt, CN = R3
   i:C = US, O = Internet Security Research Group, CN = ISRG Root X1
 2 s:C = US, O = Internet Security Research Group, CN = ISRG Root X1
   i:O = Digital Signature Trust Co., CN = DST Root CA X3
Which is interesting as the ISRG Root X1 is also in the root store. But it's also cross-signed to the DST Root CA.

Checking the verification steps (and not the chain as given out by the server) gives the new path already:
depth=2 C = US, O = Internet Security Research Group, CN = ISRG Root X1
verify return:1
depth=1 C = US, O = Let's Encrypt, CN = R3
verify return:1
depth=0 CN = koos.idefix.net
verify return:1
This is a subtle but important difference.

Only hours left until the DST Root expires:
$ openssl x509 -in DST_Root_CA_X3.crt -noout -enddate
notAfter=Sep 30 14:01:15 2021 GMT
If services break after 14:01:15 GMT (UTC) today you're not working according to best practices (replacing the certificate chain with every certificate replacement) or you have old clients.

Slight update: I requested a new LetsEncrypt certificate for a service after 14:01:15 GMT (UTC) and it still has the certificate chain with cross-certification to DST Root CA X3:
Certificate chain
 0 s:CN = koos.idefix.net
   i:C = US, O = Let's Encrypt, CN = R3
 1 s:C = US, O = Let's Encrypt, CN = R3
   i:C = US, O = Internet Security Research Group, CN = ISRG Root X1
 2 s:C = US, O = Internet Security Research Group, CN = ISRG Root X1
   i:O = Digital Signature Trust Co., CN = DST Root CA X3
The verification steps are as above.

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2021-09-29 Spam/phishing/fraude woningnet 2 weeks ago
Cybercriminal Het nieuws over de woningmarkt in nederland is blijkbaar ook opgepikt door de fraudeurs die graag mensen geld afhankelijk maken.

Onderstaande uit de inkomende berichten. Keurig alle kenmerken van een poging fraude: urgentie 'binnen 2 weken' en vervelende consequenties als de gebruiker niets doet 'Uw opgebouwde inschrijfduur en eventuele reacties vervallen dan'.

Allemaal vooral tekenen van een poging tot oplichting. Trap hier niet in. Meer informatie bij Diverse onderwepen Klik op “Lees meer” - fraudehelpdesk.nl.
Geachte klant,

Uw inschrijving bij WoningNet

Over 2 weken verloopt uw inschrijving. Uw inschrijving verlengen wij met een
jaar als u de verlenginskosten van


Factuurnummer: SRA-00717113

Wilt u betalen via een doorlopende machtiging? dit kan, nadat u dit jaar nog
via iDEAL betaald heeft. U kunt na de betaling bij overzicht van mijn gegevens
uw betaalwijze veranderen.

Volgend jaar zullen wij dan de verlengingskosten van uw rekening incasseren.
Ook hiervan krijgt u via e-mail een bericht. Meer informatie over betalen van
de verlengingskosten vindt u op onze website.


Als u niet binnen 2 weken betaalt, schrijven wij u uit. Uw opgebouwde
inschrijfduur en eventuele reacties vervallen dan.
De url voor de 'WoningNet-verlengingskosten' :
t.co is de url-verkorter van twitter.

Gaat door naar:
Een andere url-verkorter.

Gaat door naar:

0mgeving-online.ga.     3511    IN      A
En die reageert op dit moment niet. Opvallend: Er is ook (nog) geen certificaat voor bekend in de CT-logs.

Update: Aparte vermelding nu bij fraudehelpdesk.nl met voorbeeld: Lidmaatschap behouden - Fraudehelpdesk.

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2021-09-28 Debugging a systemd issue .. without having to curse 2 weeks ago
Today I ran into an issue related to systemd and I decided to try to fix it without too much cursing. The result was a number of google searches ending up on unix.stackexchange.com but eventually I fixed the problem.

At work we use splunk for security monitoring and one of the indexers failed to start the splunk processes after a reboot. On browsing the systemd boot log with journalctl -b -l I discovered that the main issue was that creating files in /opt/splunk failed. This was due to an interesting race condition: splunk may start as soon as target network.target has been reached, but mounting /opt over iscsi also needs network.target to start. So the unit file has been updated to:
Description=Systemd service file for Splunk, generated by 'splunk enable boot-start'
After=network.target opt.mount
The next problem was the systemctl start Splunkd.service failing in some intricate way. I had a look at the logging and saw that it was actually trying to restart the service and failed at killing one of the old processes. It turned out the /opt/splunk/var/run/splunk/splunkd.pid file had old contents and one of the PIDs in that file was now in use by a kernel thread. Those you can't kill, the restart failed and therefore the service did not start at all. Solution: remove the .pid file.

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2021-09-27 I participated in the CQ World Wide RTTY DX Contest 2 weeks ago
RTTY Contest on websdr Past weekend was the 2021 version of the CQ World Wide RTTY DX Contest and I participated. I had time to participate in a few intervals during the weekend and it helped that it was a 48-hour contest so I could get some more contacts in the log Sunday evening.

In the end I made 151 contacts, a really nice number.

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2021-09-23 Phishing with error messages 3 weeks ago
In the phishing mail today:
   -------- Original Message --------

   Subject: Mail delivery failed: returning message to sender

   From: Mail Delivery System
   Date: 9/23/2021 7:09:49 p.m.

   To: koos@[..]

   This message was created automatically by mail delivery software.

   Some recent messages that you sent could not be delivered to one or
   more of its recipients.
   This is a temporary error tha can be corrected.

   Reporting-MTA: dns;[1]click to retry delivery
   Action: failed
   Status: Queued on server
The 'click to retry' was a link to a phishing site. Nicely copied from a standard mailer error message. Too bad the phishing site doesn't work!

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2021-09-18 New countries in the log: Trinidad & Tobago, Taiwan and New Zealand 3 weeks ago
I haven't written about new countries I had contacts with via amateur radio for a while, but today I finally got New Zealand in the log, which has been on my wishlist for a while. Indeed all countries that I don't have in the log yet are on that wishlist, but ranked according to Clublog New Zealand should be the 'easiest' for me.

This morning I had a contact using the FT8 mode with ZL4AS on the 40 meter amateur band. This means a contact over a distance of 18726 kilometers. And by the time I write this the contact is already confirmed via Logbook of The World.

The previous new country was Taiwan, last Wednesday using FT8 on the 20 meter band. That contact was with amateur station BU2FF who also confirmed very fast.

And a while ago I had a contact with a station in Trinidad & Tobago but I haven't seen confirmation yet.

So I am still going strong with contacts on amateur radio, sometimes finding that rare opportunity for a new country.

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The person

Father, cat owned/owner, Linux fan, Internet user, book reader, radio amateur, recumbent bicyclist, snowboarder, ipv6 fan. For those who don't speak Dutch: how to pronounce Koos van den Hout.

The job

Specialist information security at Utrecht University with a modern Profile page.

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Use the e-mail address in the address box and use PGP private secure e-mail when possible.
, reachable as koos+website@idefix.net. PGP encrypted e-mail preferred. PGP key 5BA9 368B E6F3 34E4 local copy PGP key 5BA9 368B E6F3 34E4 via keyservers

Meningen zijn die van mezelf, wat ik schrijf is beschermd door auteursrecht. Sommige publicaties bevatten een expliciete vermelding dat ze ongevraagd gedeeld mogen worden.
My opinions are my own, what I write is protected by copyrights. Some publications contain an explicit license statement which allows sharing without asking permission.
Other webprojects: Camp Wireless, wireless Internet access at campsites, The Virtual Bookcase, book reviews
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