30
Sep
2012

CSAW 2012 – Reversing 500

For this challenge, we’re given two files:


8086100f.mrom: BIOS (ia32) ROM Ext. (6*512)
8086100f.mrom.tmp: ELF 32-bit LSB executable, Intel 80386, version 1 (SYSV), statically linked, not stripped

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30
Sep
2012

CSAW 2012 – Reversing 300

We’re given a Windows .NET executable (CSAWQualification.exe).

Let’s run it:
Do you really just run random binaries given to you in challenges?

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11
Jun
2012

SecuInside 2012 – Dethstarr

Dethstarr is a remote exploitation level where you first have to reverse engineer a protocol to get to the good parts.

The server program is an inetd-style program which has a socket as stdin/stdout. The main() calls a bunch of different functions which receive a blob of data from the socket and perform a *lot* of checks on it. If any of these checks fails exit() is called.

The bug is that a user-supplied array offset is not checked for negative values before writing a user-controlled value. This yields a nearly-arbitrary write primitive which can be called four times.
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21
May
2012

BaltCTF 2012 – North America300

Snake
Everybody love’s games. Just get 10000 points
https://www.dropbox.com/s/yy9jy7k2ey9alrv/ppc300.zip

Although we didn’t solve it during the CTF, here is our one-byte solution.
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02
May
2012

Plaid CTF 2012 – Mess

The biggest event of the robot year is happening this week! Robot invitations are cool in that they are just a password that validates at the door. We acquired the validator to be used. Can you find an invitation for us in time?

In this challenge we’re given an ELF binary which asks for a password. Disassembly in IDA quickly shows what the mess is all about – function pointers, lots of them.

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02
May
2012

Plaid CTF 2012 – The Game

Robots enjoy some strange games and we just can’t quite figure this one out.
Maybe you will have better luck than us.
Title: The Game (100)
Category: Potpourri

The challenge consisted of a game we could play by connecting to a service running on port 6969.
The game provided two hex strings, and our job was to find out which one was the biggest.
To get the key, we had to win 75 runs in a row.

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02
May
2012

Plaid CTF 2012 – RSA

We recently intercepted a plethora of robot transmissions but they are all encrypted with some strange scheme we just can’t quite figure out. Can you crack it?
200 points, Password Guessing, 6 teams solved this

A very cool and surprisingly easy crypto challenge: all you have to do is break 4096-bit RSA!

Of course, there are some special circumstances which make solving this possible at all. We have two files, one is the encrypted data (presumably, it is named enc.dat and looks like random data) and the other is a RSA public key in PEM format. Let’s list the details of this public key:
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02
May
2012

Plaid CTF 2012 – Chest

Robots are running secret service that aims to mill down diamonds into fairy dust, and use it to take over our world! Help us please!
300 points, Pwnables, 18 teams solved this

This is one of those challenges where just playing around with it turned out to be faster than actually figuring out what was going on.

This was a remote exploit challenge. The service in question allows you to create “chests” (or data stores) which can hold a certain amount of data. If you add more data, the chest is deleted (“blows up”). You can also destroy a chest yourself. It is possible to access a chest from more than one connection at a time, leading us to suspect a synchronization issue.
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02
May
2012

Plaid CTF 2012 – Format

Format is exactly what you’d expect: a remote format string exploit. To get to the format string takes a little bit of reversing first, but it’s not too hard.

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02
May
2012

Plaid CTF 2012 – Paste

Robot hackers, like their human counter parts, have a largely unmet need to dump large amounts of text to their peers. We recently got access to one of their servers and are providing you with the files. What have they been talking about?
Title: Paste (100)
Category: Practical Packets

This challenge is a webapplication, a pastebin for robot hackers. Luckily the humans got the source code. It contains an admin cookie employing the well known ‘security by obscurity’ method, a questionable preg_replace statement using eval mode and an unchecked require. What can we do with those?
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