Capture-the-Flag

PDF is Broken: a justCTF Challenge

Evan Sultanik
Trail of Bits sponsored the recent justCTF competition, and our engineers helped craft several of the challenges, including D0cker, Go-fs, Pinata, Oracles, and 25519. In this post we’re going to cover another of our challenges, titled PDF is broken, and so is this file. It demonstrates some of the PDF file format’s idiosyncrasies in a […]

What do La Croix, octonions, and Second Life have in common?

Trail of Bits
This year for CSAW CTF, Trail of Bits contributed two cryptography problems. In the first problem, you could combine two bugs to break DSA much like the Playstation 3 firmware hackers. The other challenge–-weirder and mathier–-was split into two parts: one for the qualifiers, one in finals. This challenge, “Holywater,” was some of the most […]

CSAW CTF Crypto Challenge: Breaking DSA

Trail of Bits
The Trail of Bits cryptographic services team contributed two cryptography CTF challenges to the recent CSAW CTF. Today we’re going to cover the easier one, titled “Disastrous Security Apparatus – Good luck, ‘k?” This problem involves the Digital Signature Algorithm (DSA) and the way an apparently secure algorithm can be made entirely insecure through surprising […]

Hands on the Ethernaut CTF

Josselin Feist
Last week Zeppelin released their Ethereum CTF, Ethernaut. This CTF is a good introduction to discover how to interact with a blockchain and learn the basics of the smart contract vulnerabilities. The CTF is hosted on the ropsten blockchain, and you can receive free ethers for it. The browser developer console is used to interact […]

An extra bit of analysis for Clemency

This year’s DEF CON CTF used a unique hardware architecture, cLEMENCy, and only released a specification and reference tooling for it 24 hours before the final event began. cLEMENCy was purposefully designed to break existing tools and make writing new ones harder. This presented a formidable challenge given the timeboxed competition occurs over a single […]

Magic with Manticore

Manticore is a next-generation binary analysis tool with a simple yet powerful API for symbolic execution, taint analysis, and instrumentation. Using Manticore one can identify ‘interesting’ code locations and deduce inputs that reach them. This can generate inputs for improved test coverage, or quickly lead execution to a vulnerability. I used Manticore’s power to solve Magic, a challenge […]

2000 cuts with Binary Ninja

Using Vector35’s Binary Ninja, a promising new interactive static analysis and reverse engineering platform, I wrote a script that generated “exploits” for 2,000 unique binaries in this year’s DEFCON CTF qualifying round. If you’re wondering how to remain competitive in a post-DARPA DEFCON CTF, I highly recommend you take a look at Binary Ninja. Before […]

Why we give so much to CSAW

In just a couple of weeks, tens of thousands of students and professionals from all over the world will tune in to cheer on their favorite teams in six competitions. If you’ve been following our blog for some time, you’ll know just what we’re referring to: Cyber Security Awareness Week (CSAW), the nation’s largest student-run […]

Flare-On Reversing Challenges 2015

Trail of Bits
This summer FireEye’s FLARE team hosted its second annual Flare-On Challenge targeting reverse engineers, malware analysts, and security professionals. In total, there were eleven challenges, each using different anti-reversing techniques and each in different formats. For example, challenges ranged from simple password crack-mes to kernel drivers to stego in images. This blogpost will highlight four […]

Closing the Windows Gap

Ryan Stortz
The security research community is full of grey beards that earned their stripes writing exploits against mail servers, domain controllers, and TCP/IP stacks. These researchers started writing exploits on platforms like Solaris, IRIX, and BSDi before moving on to Windows exploitation. Now they run companies, write policy, rant on twitter, and testify in front of […]

Trail of Bits Releases Capture the Flag Field Guide

Free Online Coursework Allows Students, Professionals to Build Essential Offensive Security Skills New York, NY (May 20, 2014)–Security researchers at Trail of Bits today introduced the CTF Field Guide (Capture the Flag), a freely available, self-guided online course designed to help university and high school students hone the skills needed to succeed in the fast-paced, […]