You can parse the binary blobs that represent certificates stored in the Windows registry with certutil correctly, even when the Windows Explorer / GUI tells you that this is not a certificate. certutil seems to be able to handle / ignore meta data better. Once upon a time I played with the machine Ethereal provided by … Continue reading Parse Certificates Stored in the Windows Registry
You want this: Encrypt a message to somebody else - using information that is publicly available. Somebody else should then be able to decrypt the message, using only information they have; nobody else should be able to read this information. The public key cryptography algorithm RSA does achieve this. This article is my way of … Continue reading The RSA Algorithm
This is about a serious misconfiguration of a Windows Public Key Infrastructure integrated with Active Directory: If you can edit certificate templates, you can impersonate the Active Directory Forests's Enterprise Administrator by logging on with a client certificate. You have a persistent credential that will also survive the reset of this admin's password. In the … Continue reading Impersonating a Windows Enterprise Admin with a Certificate: Kerberos PKINIT from Linux
Last year, hackthebox let me test something I have always found fascinating - and scary: You can impersonate any user in a Windows Active Directory Forest if you have control over the certificate templates of an AD-integrated Windows Public Key Infrastructure: Add extended key usages for smartcard logon to the template, enroll for the certificate, … Continue reading Locating Domain Controllers and Spoofing Active Directory DNS Servers
Another great machine has been retired on hackthebox.eu - Helpline by @egre55! Here is my 'silly' unintended way to root the box: You can get both the encrypted user and root flag via the cumbersome web RCE alone - if you wait for a legit user to just look at the file. This is unlikely … Continue reading Helpline @ hackthebox: Injecting an EFS Recovery Agent to Read Encrypted Files
My writeup - how to pwn my favorite box on hackthebox.eu, using a (supposedly) unintended path. Sizzle - created by @mrb3n813 and @lkys37en - was the first box on HTB that had my favorite Windows Server Role - the Windows Public Key Infrastructure / Certification Authority. This CA allows a low-privileged user - amanda - … Continue reading Sizzle @ hackthebox – Unintended: Getting a Logon Smartcard for the Domain Admin!
Just dumping some quick and dirty one-liners! These are commands I had used to explore locked-down Windows and Linux machines, using bash or powershell when no other binaries were available or could be transferred to the boxes easily. Trying to ping all hosts in a subnet Linux for i in $(seq 1 254); do host=192.168.0.$i; … Continue reading Simple Ping Sweep, Port Scan, and Getting Output from Blind Remote Command Execution
How to transfer small files to a locked-down Windows machine? When there is no option to copy, ftp, or http GET a file. When powershell is blocked so that you can only use Windows cmd commands? My first choice would be to use certutil: certutil is a built-in tool for certificate and PKI management. It … Continue reading Echo Unreadable Hex Characters in Windows: forfiles
This post is related to the 'insanely' difficult hackthebox machine Ethereal (created by egre55 and MinatoTW) that was recently retired. Beware - It is not at all a full comprehensive write-up! I zoom in on openssl, X.509 certificates, signing stuff, and related unnecessary rabbit holes that were particularly interesting to me - as somebody who … Continue reading Ethereal @ hackthebox: Certificate-Related Rabbit Holes
Some public key infrastructures run quietly in the background since years. They are half forgotten until the life of a signed file has come to an end - but then everything is on fire. In contrast to other seemingly important deadlines (Management needs this until XY or the world will come to an end!) this … Continue reading Certificates and PKI. The Prequel.