Hey everybody, In addition to genius, whose writeup I already posted, my other favourite challenge I wrote for BSidesSF CTF was called launchcode. This will be my third and final writeup for BSidesSF CTF for 2019, but you can see all the challenges and solutions on our Github releases page. This post will be more […]
Hey all, This is going to be an author's writeup of the BSidesSF 2019 CTF challenge: genius! genius is probably my favourite challenge from the year, and I'm thrilled that it was solved by 6 teams! It was inspired by a few other challenges I wrote in the past, including Nibbler. You can grab the […]
This is a technical rundown of a vulnerability that we've dubbed "WebExec". The summary is: a flaw in WebEx's WebexUpdateService allows anyone with a login to the Windows system where WebEx is installed to run SYSTEM-level code remotely. That's right: this client-side application that doesn't listen on any ports is actually vulnerable to remote code […]
Welcome to my fourth and final writeup from Ghost in the Shellcode 2015! This one is about the one and only reversing level, called "huffy", that was released right near the end. Unfortunately, while I thought I was solving it a half hour before the game ended, I had messed up some timezones and was […]
This is my writeup for byhd, a 2-point challenge from the Defcon Qualifier CTF. You can get the files, including my annotated assembly file, here. This is my second (and final) writeup for the Defcon Qualifiers, you can find the writeup for shitsco here. This was a reverse engineering challenge where code would be constructed […]
Hey folks, This is my last writeup for PlaidCTF! You can get a list of all my writeups here. Kappa is a 275-point pwnable level called Kappa, and the goal is to capture a bunch of Pokemon and make them battle each other! Ultimately, this issue came down to a type-confusion bug that let us […]
I know what you're thinking of: what's with all the Web levels!? Well, I was saving the exploitation levels for last! This post will be about Pwnable-200 (ezhp), and the next one will be Pwnable-275 (kappa). You can get the binary for ezhp here, and I highly recommend poking at this if you're interested in […]
Hey folks, It's a little bit late coming, but this is my writeup for the Fuzzy level from the Ghost in the Shellcode 2014 CTF! I kept putting off writing this, to the point where it became hard to just sit down and do it. But I really wanted to finish before PlaidCTF 2014, which […]
"It's Saturday night; I have no date, a 2L bottle of Shasta, and my all-rush mix tape. Let's rock!" ...that's what I said before I started gitsmsg. I then entered "Rush" into Pandora, and listened to a mix of Rush, Kansas, Queen, Billy Idol, and other 80's rock for the entire level. True story. Anyway, […]
Hey everybody, This past weekend was Shmoocon, and you know what that means—Ghost in the Shellcode! Most years I go to Shmoocon, but this year I couldn't attend, so I did the next best thing: competed in Ghost in the Shellcode! This year, our rag-tag band of misfits—that is, the team who purposely decided not […]
Hey folks, Happy New Year, and welcome to 2014! On a recent trip to Tyson's Corner, VA, I had some time to kill, so I took a careful look at a malware sample that a friend of mine sent to me some time ago, which I believe he originally got off somebody else's hosed system. […]
One of the worst feelings when playing a capture-the-flag challenge is the hindsight problem. You spend a few hours on a level—nothing like the amount of time I spent on cnot, not by a fraction—and realize that it was actually pretty easy. But also a brainfuck. That's what ROP's all about, after all! Anyway, even […]
When I was at Shmoocon, I saw a talk about how to write an effective capture-the-flag contest. One of their suggestions was to have a tar-pit challenge that would waste all the time of the best player, by giving him a complicated challenge he won't be able to resist. In my opinion, in PlaidCTF, I […]
Hey everybody, There have been a lot of discussion and misconceptions about Battle.net's authentication lately. Having done a lot of work on the Battle.net protocol, I wanted to lay some to rest. The first thing to understand is that, at least at the time I was working on this, there were three different login methods […]
Hey guys, Today, I thought it'd be fun to take a good look at a serious flaw in some computer-management software. Basically, the software is designed for remotely controlling systems on networks (for installing updates or whatever). As far as I know, this vulnerability is currently unpatched; there are allegedly mitigations, but you have to […]
Hey everybody, Two weeks ago today, Microsoft released a bunch of bulletins for Patch Tuesday. One of them - ms11-058 - was rated critical and potentially exploitable. However, according to Microsoft, this is a simple integer overflow, leading to a huge memcpy leading to a DoS and nothing more. I disagree. Although I didn't find […]
Hey everybody, As I'm sure you all know, I normally post about IT security here. But, once in awhile, I like to take a look at physical security, even if it's just in jest. Well, this time it isn't in jest. I was at Rona last week buying a lead/asbestos/mold-rated respirator (don't ask!), when I […]
Hey everybody, Most of you have probably heard of the exim vulnerability this week. It has potential to be a nasty one, and my brain is stuffed with its inner workings right now so I want to post before I explode! First off, if you're concerned that you might have vulnerable hosts, I wrote a […]
Now that we know what we need to send and receive, and how it's encoded, let's generate the actual packet. Then, once we're sure it's working, we'll convert it into an Nmap probe! In most of this section, I assume you're running Linux, Mac, or some other operating system with a built-in compiler and useful […]
In Part 2: runtime analysis, we discovered some important addresses in the Energizer Trojan -- specifically, the addresses that make the call to recv() data. Be sure to read that section before reading this one. Now that we have some starting addresses, we can move on to a disassembler and look at what the code's […]