NARAYAN KHADKA 9808415891

NARAYAN KHADKA

"PHoss is a sniffer. A normal sniffer software is designed to find problems in data communication on the network. PHoss is designed to know some protocols which use (or may use) clear text passwords. Many protocols are designed to use secure authentication. For fallback they define a lowest level of authentication using clear text. Many companies use this lowest fallback definition as standard setting to make the product working in many environments." read more...

Download: http://www.phenoelit-us.org/phoss/download.html

"Odysseus is a tool designed for testing the security of web applications. Odysseus is a proxy server, which acts as a man-in-the-middle during an HTTP session. A typical HTTP proxy will relay packets to and from a client browser and a web server. Odysseus will intercept an HTTP session's data in either direction and give the user the ability to alter the data before transmission. For example, during a normal HTTP SSL connection a typical proxy will relay the session between the server and the client and allow the two end nodes to negotiate SSL. In contrast, when in intercept mode, Odysseus will pretend to be the server and negotiate two SSL sessions, one with the client browser and another with the web server." read more...

Download: http://www.bindshell.net/tools/odysseus

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NARAYAN KHADKA

The remote service ask for a name, if you send more than 64 bytes, a memory leak happens.
The buffer next to the name's is the first random value used to init the srand()

If we get this value, and set our local srand([leaked] ^ [luckyNumber]) we will be able to predict the following randoms and win the game, but we have to see few details more ;)

The function used to read the input until the byte \n appears, but also up to 64 bytes, if we trigger this second condition there is not 0x00 and the print shows the random buffer :)

The nickname buffer:

The seed buffer:

So here it is clear, but let's see that the random values are computed with several gpu instructions which are decompiled incorrectly:

We tried to predict the random and aply the gpu divisions without luck :(

There was a missing detail in this predcitor, but there are always other creative ways to do the things.
We use the local software as a predictor, we inject the leaked seed on the local binary of the remote server and got a perfect syncronization, predicting the remote random values:

The process is a bit ugly becouse we combined automated process of leak exctraction and socket interactive mode, with the manual gdb macro.

The macro:

NARAYAN KHADKA 9808415891

TIME

Wednesday, January 24, 2024

PHoss: A Password Sniffer

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