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Jeroen W. Pluimers on .NET, C#, Delphi, databases, and personal interests

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Archive for the ‘SPAM’ Category

Did not realise that a 2018 Mikrotik vulnerability made it to the top of the CBL (SMTP composite black list) warning page for quite some months as the first ever device

Posted by jpluimers on 2021/07/02

Having it accidentally made it to the CBL (Composite Blocking List – Wikipedia) a long time ago, I discovered the page started with (WayBack link mine):

IMPORTANT: Many CBL/XBL listings are caused by a vulnerability in Mikrotik routers. If you have a Mikrotik router, please check out the [WayBack] Mikrotik blog on this subject and follow the instructions before attempting to remove your CBL listing.

It wasn’t one of my Mikrotik devices, as first of all they had all being patched out of the box from a really empty internal network before being externally exposed to the internet or more busy internal networks, and second because the CBL entry was a one off on one specific day where someone used our guest network.

Some CBL entries in the range where it was displayed, quite a while after CVE-2018-14847 became public:

If you want to try for yourself or harden it: [WayBack] Exploiting Mikrotik for Good ? | Syed Jahanzaib Personal Blog to Share Knowledge !

So I did some more digging.

First of all, it seems that if you ever had an infected Mikrotik system, then you have to factory reset it, then upgrade and configure from scratch. Otherwise at least the SOCKS and Web proxy services can still send out spam: [] spammer behind mikrotik or mikrotik is the spammer : sysadmin. There, the best advice was

aliterCogitare, Jr. Sysadmin: 

Your mikrotik has been compromised then, I would suggest either going on site and rebuilding the router from scratch, or looking at a few things:

  1. Check System -> Scheduler for any schedules running( that you haven’t configured yourself)

  2. Check Systems -> scripts for any installed scripts that are running and delete, also look for running jobs and terminate them.

  3. Finally check the file explorer for any suspicious files or scripts, and delete any you find. A default library should look like this: flash (the partition) -pub -skins anything else that you havent put there yourself, Delete.

Anything else that I have mentioned above should be empty. Also you need to re-evaluate the security of your network. If you happen to be on site, reset the router and remove the default configuration on the boot prompt. Create two rules:

  • Allow input chain source IP from your default local network, if i remember correctly its

  • create an explicit drop rule on input chain for all interfaces and addresses + ports

  • disable IP – services except winbox Finally work your way up on what your network needs step by step by creating rules to accept traffic. And be sure to put your explicit rule on the bottom of the list by drag-and-dropping. That is all I can say, I hope I could be of help.

This means the advice in these two links might not be enough:

Another helpful resource [WayBack] Router Sending Spam – MikroTik which discusses the firewall rules, socks and web proxy services.

Second, there are a truckload of these devices around: [WayBack] Thousands of Compromised MikroTik Routers Send Traffic to Attackers and [WayBack] Thousands of MikroTik routers are snooping on user traffic | ZDNet write that in September 2018, at least 7500 devices were known infected and about 370-thousand endpoints vulnerable.

Third, you should be able to use [WayBack] Manual:Tools/Netwatch – MikroTik Wiki to check if you are on the CBL: [WayBack] Probing CBL blacklist – MikroTik.

Read the rest of this entry »

Posted in Firewall, Internet, MikroTik, Power User, Routers, SPAM | Leave a Comment »

SPAM – Garantiebellen – +31172749040 – ‘Hang op! Klik weg! Bel uw bank!’ – #KVK doe er wat aan!

Posted by jpluimers on 2016/09/21

Onder het mom van ‘Hang op! Klik weg! Bel uw bank!’:

Ik werd net gebeld door +31172749040 die zich bekend maakten als “Garantie Bellen” en onder het mom van “partner van KPN” je proberen een nieuw abonnement met lagere tarieven aan te smeren.

Hun web-site meldt dat ze in Rotterdam zitten:

Hun algemene voorwaarden echter Utrecht:

Garantie Bellen, Churchilllaan 11, 3527 GV in Utrecht

Op de hele site geen informatie van het handelsregister, dus ze plegen sowieso een economisch delict:

Het niet naleven van de verplichting om het KvK-nummer te vermelden is een economisch delict (art. 1 sub 4 WED). Het is een overtreding die wordt gestraft met hechtenis van ten hoogste zes maanden, taakstraf of een geldboete van de vierde categorie (dat wil zeggen ten hoogste €19.000,-).

Die heb ik inmiddels zelf gevonden: 61233927 met als informatie:

Naam:  To the Max Callcenter B.V.
Vestigingsadres:    Westblaak  142  
Vestigingsplaats:   3012KM  Rotterdam
KvK-nummer: 61233927
Vestigingsnummer:   000030351928
Soort Inschrijving: Hoofdvestiging

To the Max Callcenter B.V.Hoofdvestiging
Bestaande handelsnamen
To the Max Callcenter B.V. | Garantiebellen | Garantie-bellen
Statutaire naam
To the Max Callcenter B.V.
KvK 61233927Vestigingsnr. 000030351928Westblaak 142 3012KMRotterdam
61233927 0000 000030351928 To the Max Callcenter BV. To the Max Callcenter BV, Garantiebellen, Garantie-bellen. Callcenters. …


Posted in Power User, SPAM | 3 Comments »

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