Session
Programm CCCamp 2019
Security

Domain computers have accounts, too!

Owning machines through relaying and delegation
In Microsoft Active Directory, computers also have their accounts. We used to consider them useless when they turned up during pentests, but recent research showed that successfully relaying a machine account can actually lead to completely owning the machine. This talk will explain the foundation of such attacks and end with a demonstration of how a non-privileged domain user can get SYSTEM privileges on remote machines.

Active Directory is notorious for using long-broken protocols and preserving them for ages because backwards compatibility. In recent years, pentesters are realizing more and more how terrible these protocols can be, and security experts are finding more and more abuse scenarios.

Take for example the NTLMv2 challenge-response protocol: It was first introduced back in Windows NT 4.0 SP4 and is still readily available on modern windows. Apart from not being very resistant to cracking (using just a few MD5s), it turned out it's not resistant to MITM attacks at all. An attacker in a MITM position can relay any authentication attempts to almost any target. There were some mitigitations for this over the years, but we are just now starting to see people actually starting to use them.

So when relaying came to existence, security researches focused on "what can we do with this"? Obviously, if you manage to succesfully relay a Domain Administrator account, you have won; but that's not always possible.

Another protocol used extensively in Active Directory is Kerberos. The Microsoft implementation has several delegation/impersonation techniques available. And now, we know how to combine all these to be able to impersonate any user to a computer, given we were able to relay that computer's authentication at least once.

The talk will cover these main areas:

NTLM Relaying

Kerberos delegation

Getting machines to authenticate to us

All tools necessary to perform this attack will be released as impacket modules.

This talk is mainly based on research by @tifkin_ (Lee Christensen), @harmj0y (Will Schroeder), @enigma0x3 (Matt Nelson), @elad_shamir (Elad Shamir), @_dirkjan (Dirk-jan).

Additional information

Type lecture
Language English

More sessions

8/21/19
Security
Thomas Fricke
Curie
The talks shows the security model of Kubernetes and how to detect and fight security weaknesses with a few lines of scripting.
8/21/19
Security
Carsten Strotmann
Meitner
Seldom have DNS protocol changes sparked such fierce debate as happen in the case of DNS-over-HTTPs (Doh) and it's little cousin, DNS-over-TLS (DoT). While for many people it is a matter of black and white, the reality out there is various shades of grey ;) This talk will discuss the technical and political aspects of these DNS privacy protocols, where they come from, who is implementing DoH/DoT (both in the browser space and otherwise) and why it is a [good|bad] idea to support these protocol ...
8/21/19
Security
Egor
Meitner
Typical home networks use a closed-source Internet Service Provider supplied router/firewall and contain no restrictions on communications between clients within the network. The widespread deployment of network-connected appliances, control systems, lighting, etc, means that this design is insecure. This talk will cover the basics of networking, including why and how segregation of different types of network clients and traffic can be achieved to increase privacy and security.
8/21/19
Security
Meitner
We have learned that Math might be our last defence line against a real existing all-encompassing surveillance. One central challenge in this conflict is to combine authentication and anonymity. Number theory provides us many tools to create really surprising technologies for social communication. A lot of these technologies have not yet been brought to the world of concrete implementations. This has the implication that some ideas which have been presented years ago are not covered by patents ...
8/21/19
Security
Dennis Giese
Meitner
Remember the good old fun sport, where people bought random hard drives from ebay and did forensics on them? Did you know you can do the same thing with used IoT devices too? Most end-users have no idea what kind of information their devices are storing and how to securely clean their devices (if that even is possible). Lets explore together what the risks are and how we can extract that data.
8/22/19
Security
Eileen Wagner
Curie
This case study of NoScript’s UX redesign showcases tried and true design principles that make security tools usable to a wider range of audiences.
8/22/19
Security
cy
Curie
i'll show how the average developer (like me) can secure their software and systems by automatically checking for known vulnerabilities and security issues as part of their CI-Toolchain. The Talk will introduce basic security knowhow, then show how you can use Open Source Frameworks to check for vulnerable dependencies, containers and (web-)APIs in a live demo