PTS22

Pass-The-Salt 2022 Wrap-Up

Conferences are back! After Botconf in April, that’s Pass-The-Salt that is organized this week in Lille, France. After the two years break, the formula did not change: same location, free, presentations around security, and free software! And, most important, the same atmosphere.

The first day started in the afternoon and talks are grouped by topic. The first one was cryptography, hard way to start the conference if, like me, you don’t like this. But, the talks were interesting anyway! The first one was “Mattermost End-to-End Encryption plugin” by Adrien Guinet & Angèle Bossuat. Mattermost is a very popular free chat service (like Slack) but a free version is available and the community around it creates a lot of plugins. Encryption is in place between the client and the server but there was a lack of E2EE or “End-2-End Encryption” (so that even administrators of the server can’t see messages and files exchanged). The plugin was not easy to implement due to the Mattermost limitations: notifications, attachments, modification of sent messages, etc. Adrien & Angèle explained how they implemented this, how they solved some challenges, and ended with a quick demo. The plugin is available here if interested.

Then, Ludovic Dubost came on stage to present “CryptPad : a zero knowledge collaboration platform”. This project is already six years old and, even if I’ve heard about it, I never used it. Cryptpad tries to solve all privacy issues with data (example: the cloud by definition). Today, in most cases, it’s all about trust. The situation between the two parties has been widely accepted and let’s sign contracts instead. Cryptpad helps you to work on many documents and share them with your peers. Its key points are encrypted docs that can be edited in real time, E2EE, and key management with secure and private key sharing. Server owners have access to nothing (even recover data). Some features:

  • Create application files (docs, presentations, pads, kanban, surveys, code, forms, …
  • Crypt drive
  • Sharing functions
  • Work in teams

A good resume could be “Get people out of Google Docs”. Another good fact: it requires a low amount of resources. More information on cryptpad.org.

Then, another tool was presented by Yves Rutschle: “Dataflow tabular charts — a presentation tool for security architects”. The tool is called dtc.pl, yes, written in Perl! Its purpose is to create SVG files that will represent drawings of complex infrastructure or systems but the file is generated based on descriptions in a text file. Example:

Human:
-> Human (6)
void / void / void / void / void / Human Content
Reader laptop:
...

The tool is available here.

The second round of sessions focused on operating systems security. Mickaël Salaün presented “Sandboxing your application with Landlock, illustration with the p7zip case”. Landlock is not new but not known by many people. It’s enable by default on many systems like Ubuntu 22.04-LTS. It’s a software sandboxing systems that allows to restrict access to applications. It must be implemented by developers and is based on only three syscalls! Mickaël explained the system (how to enable it, create rules and populate them) and them applied it to a popular utility, 7zip to add sandboxing capabilities.

The last presentation of the day was “Building operating systems optimized for containers, from IoT to desktops and servers” by Timothée Ravier. The idea behind the talk was to explain how operating systems can be improved by using other techniques like containers to reduce the attack surface. Indeed, many OS are deployed today with plenty of tools that, because software have bugs, increase the attack surface for attackers. The idea is to reduce this amount of software to the bare minimum and deploy them with other technique to make them easier to patch.

The second day started with a series of presentations around networks. Yves Rutschle came back for a a second time with “sslh — an applicative-level protocol multiplexer“. Yves started this project years ago because he’s a big fan of console mail clients like Mutt and would like to have access to a SSH server from anywhere. In 2000, when firewalls started to filter the outgoing traffic, he developed the first version of sslh. The idea is to let sslh to listen to a port (TCP/443) and, depending on the first bytes of the session, redirect the incoming connection: Apache, the SSH server, etc. With time, it expanded, was rewritten C, as a daemon etc… Today, his tool is integrated into many Linux distributions. It also supports more protocols like OpenVPN, XMPP. The tools is available on Yves’s github repo but also available as a package in your favorite Linux distribution.

The next slot was assigned to Eric Leblond who, as usual, came to speak about the Suricata eco-system: “Write faster Suricata signatures easier with Suricata Language Server“. This time, nothing related to the tool in itself but he focused on a recurrent and annoying task: to write Suricata rules. The classic process looks like: write a rule, test it, fine-tune it, test it, … Very complex signatures can be complex to write. Because, he received multiple time the question: “How to write Suricata signature?”, he developed a solution based on the Language Server Protocol: “SLS” or “Suricata Language Server”. From your preferred text editor (lot of them are supported), you can get help, auto-completion, verification directly when you write Suricata rules. Really interesting if you write a lot of them!

The next one was “Building on top of Scapy: what could possibly go wrong?” by Claire Vacherot who’s a pen tester active in the ICS field. She explained their needs for specific tools. They create a framework (BOF – “Boiboite Opener Framework”) but they faced a lot of problems and tried to find an alternative with Scapy. Scapy was not immediately effective so they decided to keep both and use BOF as a frontend for Scapy. Best conclusion: Don’t just use tools, learn the power of them! make the most of them!

After the welcomed coffee break, we switched to other talks. The next one was “Use of Machine and Deep Learning on RF Signals” by Sébastien Dudek. RF signals are used everywhere and a lot of researchers try to look at them to check many risks are related to them (jamming, eavesdropping, replay, inject, …) but the very first challenge is to get a good idea about the signals. What are we capturing? Sébastien explained briefly how to get some signals from very expensive devices to “gadgets” connected to free software. His research was to use machine learning and deep learning to help identifying the discovered signals. As I don’t have experiences in these domains (nor RF nor ML), it was a bit complex to follow but the idea seems interesting. I just bookmarked this site which helps to identify RF signals patterns: sigidiki.com.

The keynote was given by Ivan Kwiatkowski: “Ethics in cyberwar times”. It was a great talk and an eye-opener for many of us (well, I hope). The common thread was related to thread intelligence. How it is generated, by who, what companies do with it (and by they buy it!). For Ivan, “TI resellers are intelligence brokers”. Also, can there be neutal, apolitical intelligence? This is a huge debate! Everybody uses TI today: APT groups conduct attacks, TI companies write reports and APT groups buy these reports to improve their attacks. What could go wrong?

After the lunch break, we started a série about reverse and binary files. 

Abusing archive-based file formats” by Ange Albertini. Once again, Ange covered his techniques and tools to abuse file formats and create “malicious” documents. I recommend you to have a look at his Github repo.

Then, Damien Cauquil presented “Binbloom reloaded”. The first version of this tool was published in 2020 by Guillaume Heilles. Damien stumbled upon an unknown firmware… First reflex, load it into Ghidra but it was not easy to guess the base address to start the analysis. He started other tools like basefind.py without luck. He reviewed these tools and explained how they search for the base addresses. Finally, he decided to dive into binbloom and improve it. The tool is available here.

Then another tool was presented by Jose E. Marchesi: “GNU poke, the extensible editor for structured binary data“. Honestly, I never of this hex editor. They are plenty of them in the open source ecosystem but Jose explained they weaknesses. Poke looks extremely powerful to extract specific information and convert them to update the file but I was a bit lost in the details. The tool looks complex at a first sight!

To wrap-up the schedule, Romain Thomas presented something pretty cool: “The Poor Man’s Obfuscator“. The idea of his research was to transform a ELF file (Linux executable) or Mach-O (Macos executable) to make them obfuscated and not easy to debug using classic debuggers/disassemblers. Of course, the modified binaries have to remain executable from an OS point of view. Several techniques were covered like creating a lot of exports with random names or confusing names. Another technique was to alter the sections of the file. Really interesting techniques to seem very powerful. With one sample, he was able to crash Ghidra!

The day finished with a series of rump sessions and the social event in the center of Lille. The day three started with talks related to blueteams. The first one was “Sudo logs for Blue Teamers” by Peter Czanik. Peter is an advocate for Sudo & Syslog-NG, two useful tools for your Linux distributions. Both are integrated smoothly because Sudo logs are parsed automatically by Syslog-NG. IO Logs API is a nice feature that many people don’t know: you can interact with the user session. Ex: Use a few lines of Python code to terminate the session if some text if detected. Peter covered the new features like the possibility to execute a chroot with Sudo. Recap of the new versions: more logging capabilities, track and intercept sub-commands.

The next presentation focused on another tool: “DFIR-IRIS – collaborative incident response platform” presented by Théo Letailleur (&) and Paul Amicelli. As incident handlers, they came with problems to solve: Track elements during investigations, share pieces of information between analysts and handle repetitive tasks. Many solutions existed: TheHive, FIR, Catalyst, DRIFTrack, Aurora. They decided to start their own tool: DFIR-IRIS. It provides the following components:

  • python web application (API, modules)
  • automation (enrichment, reports)
  • collaboration (notes, share, tasks)
  • tracking (IOCs, assets, timeline, evidences)

I was surprised by the number of features and the power of the tool. I’m not using at this time (I use TheHive) but it deserves to be tested! More information here.

The next speaker was Solal Jabob, another regular PTS speaker! This time, he presented: “TAPIR : Trustable Artifact Parser for Incident Response“. Based on what he demonstrated, the amount of work is simply crazy. It’s a complete framework that you can use to collect artefacts and perform triage, export, … It is based on a library (TAP) used to parse data from files, disk images, … then plugins are use to extract metadata. The first tool is presented is Bin2JSON, then TAP-Query, TAPIR is a client/server solution with a REST-API, multi-user capabilities. It is command line or web based. A Python library is also available (TAPyR).

Just before the lunch break, I presented “Improve your Malware Recipes with Cyberchef“. I explained how this tool can be powerful to perform malware analysis.

After the break, the second half of the day was dedicated to pentesting / readteaming presentations. Quickly, we had Antoine Cervoise who presented “MobSF for penetration testers“. MobSF is a free open-source security scanner for mobile applications. He demonstrated how he can find interesting information to be used in his pentest projects. Hugo Vincent presented “Finding Java deserialization gadgets with CodeQL”. Java deserialization remains a common issue in many applications in 2022. It’s still present in the OWASP Top-10. Hugo explained the principle behind this attack, then demonstrated, with the help of CodeQL (a static code analyzer) how he can find vulnerabilities. Pierre Milioni presented “Dissecting NTLM EPA & building a MitM proxy“. NTML is an old protocol but still used to authenticate users on web applications. Microsoft expanded it to “EPA” for “Extended Protection for Authentication”. This make some tools useless because they don’t support this protocol extension. Pierre developed a MitM proxy called Proxy-Ez that helps to use these tools. Finally, Mahé Tardy presented “kdigger: A Context Discovery Tool for Kubernetes Penetration Testing“. kdigger is a tool that helps to perform penetration tests in the context of a Kubernetes environment. The demo was pretty nice!

After two years “online”, it was nice to be back at Lille to meet people in real life. We were approximatively 100 attendees, great number to have time to exchange with many people! The talks have been recorded and are already online, slides as well.

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