How to block Crypto Miner (javascript)

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L3 Networker

How to block Crypto Miner (javascript)

This week I noticed a "CoinHive Javascript Detection" in the logs of our Palo Alto.

When reading on the subject I noticed that there are websites around that use Javascript to start mining Crypto coins on the users' computer.

 

https://live.paloaltonetworks.com/t5/Community-Blog/Unauthorized-Coin-Mining-in-the-Browser/ba-p/183...

 

Detailed description can be found here :

https://researchcenter.paloaltonetworks.com/2017/10/unit42-unauthorized-coin-mining-browser/

 

I noticed in the Palo Alto blog that : PANDB is able to block URLs hosting Coinhive JavaScript.

 

My question:

How does one actually block this?

When I visit for example https://coinhive.com/ and push the button "Start Mining" the CPU goes up to 100%.

L3 Networker

Re: How to block Crypto Miner (javascript)

I have found how to block this in the AntiSpyware profile.

It appears that for many of the AntiSpyware actions the default setting is alert. Even for some of the critical ones.

Not sure why this is but I will play around with the settings to see if this can be set to block.

 

Unfortunately there is an additional challange.

This site is SSL encrypted and although there is SSL decryption enabled on the firewall, the site itself is classified as "Financial Services" which is excluded from SSL decryption due to regulations.

 

So if I find the solution on how to decrypt the site, I should be able to block this.

 

Thanks,

 

L3 Networker

Re: How to block Crypto Miner (javascript)

Also found the solution how to decrypt a site that is in a category that should not be decrypted.

Problem solved.

The Crypto sites are now succesfully blocked.

Re: How to block Crypto Miner (javascript)

so do you block it by your spyware filters or it is blocked by PANDB filter? 

because to me it is still unclear how Palo blocks it (if it does)

L3 Networker

Re: How to block Crypto Miner (javascript)

It is part of the Anti Spyware module.

2017-12-12 11_15_22-FW-PA500-1.pngThe default action is alert so I changed mine to "reset-both"

 

2017-12-12 11_17_04-FW-PA500-1.png

Re: How to block Crypto Miner (javascript)

thank you! 

L2 Linker

Re: How to block Crypto Miner (javascript)

Thank you!

 

I'm really surprised this is classified as low severity? This can get onto servers and spike CPU to 100% to take down applications. 

 

Also, I don't think these mining websites should be listed as 

 

 URL nanopool.org
Category Financial Services
 

Auctions?? coinhive malware was going around injecting user's PCs......

 

URL coinhive.org
Category Auctions
 
URL minexmr.org
Category Computer and Internet Info
 
URL minexmr.com
Category Malware
 

They're saying minexmr.com is malware because it was recently used in a malware mining injection incident, however couldn't you use any miner website with the injection?

 

Needs to be a new URL PAN-DB category for Cryptocurrency, in my opinon.

 

Clean this up PAN, this is going to be one of the biggest issues in 2018 against networks in my opinion. Make this a priority.

 

Thanks, -Rags

Highlighted
L1 Bithead

Re: How to block Crypto Miner (javascript)

I feel that the Palo Alto Networks response to crypto jacking is disappointing. There is a security reaseacher that is actively tracking cryptomining domains and (as of now) is maintaining up-to-date lists of these domains. You can add the first two lists "all domains" and "all optional domains" to an External Dynamic List and then edit your exsiting Anti-Spyware policies to sinkhole those domains. As of this post, there are 3,898 domains in those two lists (combined).

 

https://zerodot1.github.io/CoinBlockerLists/

L1 Bithead

Re: How to block Crypto Miner (javascript)

I see the two CoinHive signatures have have had their severity increased to medium which is set to reset-both in our environment.

L2 Linker

Re: How to block Crypto Miner (javascript)

Thanks @kalakai for the links. Good stuff.

 

What is the advantage over using a sinkhole over just using a DBL and setting the rule to block completely?

 

Thanks, -Rags

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