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🥝 Benjamin Delpy

1 Aug, 3 tweets, 2 min read

@CraigKirby

Want to block [MS-EFSR] / #PetitPotam calls?🤔
Use RPC filters ! 🥳

put previous Tweet in a file: `block_efsr.txt` then:

> netsh -f block_efsr.txt

Just tested: it blocks remote connections & not local EFS usage

Thank you to @CraigKirby to remind us this RPC technology filter!

https://twitter.com/gentilkiwi/status/1421947898749669379

this is the kind of post/statement that Microsoft could have done rather than focusing on the NTLM relay and how client should block it.

(does not change the fact that MS must fix the noauth part of MS-EFSR)

And I still really like it

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More from @gentilkiwi

🥝 Benjamin Delpy

@gentilkiwi

27 Jul

Little #printnightmare (ep 4.3) upgrade : user-to-system as a service🥝
> Open SYSTEM prompt

connect to \\printnightmare[.]gentilkiwi[.]com (remove [ ]) with
- user: .\gentilguest
- password: password

Open 'Kiwi Legit Printer - x64', enjoy SYSTEM
(just one printer this time🤪)

Of course, video quality: video.twimg.com/tweet_video/E7…

https://twitter.com/gentilkiwi/status/1416429891592011781

And how to protect you (reminder):

https://twitter.com/gentilkiwi/status/1416429891592011781

(cause you know, Microsoft does not make statements and fix for now...)

Read 4 tweets

🥝 Benjamin Delpy

@gentilkiwi

20 Jul

@jonasLyk

Q: what can you do when you have #mimikatz🥝 & some Read access on Windows system files like SYSTEM, SAM and SECURITY?

A: Local Privilege Escalation 🥳

Thank you @jonasLyk for this Read access on default Windows😘

Ho, and this is not only SAM, but also SYSTEM & SECURITY.
So you can find "interesting" data, like:
- default windows install password (can be valid, trust me 👍)
- DPAPI computer keys (decrypt all computer private keys, etc.)
- Computer Machine account (silver ticket)
- ...

Affected versions / Not affected versions on my tests today:

Read 5 tweets

🥝 Benjamin Delpy

@gentilkiwi

17 Jul

Want to test #printnightmare (ep 4.x) user-to-system as a service?🥝
(POC only, will write a log file to system32)

connect to \\printnightmare.gentilkiwi.com with
- user: .\gentilguest
- password: password

Open 'Kiwi Legit Printer - x64', then 'Kiwi Legit Printer - x64 (another one)'

You can prevent this behavior by settings some parameters/GPO:

'Package Point and print - Approved servers'
> docs.microsoft.com/troubleshoot/w…
> admx.help/?Category=Wind…

Of course, disable outbound access to CIFS/SMB/RPC...

Very bad impersonation when: docs.microsoft.com/windows-hardwa…

Read 5 tweets

🥝 Benjamin Delpy

@gentilkiwi

30 Jun

This #printnightmare / CVE-2021-1675 is really serious 🤪

Just adapted/simplified original POC then:
*From Remote standard user to SYSTEM*

Here on a domain controller, but valid on all systems with RPC to spooler available, remote or local

➡️ disable service now (no patch yet)

As usual, video quality: video.twimg.com/tweet_video/E5…

@byt3bl33d3r

Yes, DC is 2019 and fully patched
And 'localspl.dll' is 06/06/2021 (10.0.17763.1999)

@byt3bl33d3r @allevon412 @PythonResponder

But to be transparent, I don't have a recent CPU & TPM 2.0
That might be the problem, @msftsecurity, isn't it?