Rose & Marinaldo: 6 de mai. de 2020

ASIS CTF Quals 2015 - Sawthis Writeup - Srand Remote Prediction

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:

Scanning TLS Server Configurations With Burp Suite

In this post, we present our new Burp Suite extension "TLS-Attacker".
Using this extension penetration testers and security researchers can assess the security of TLS server configurations directly from within Burp Suite.
The extension is based on the TLS-Attacker framework and the TLS-Scanner, both of which are developed by the Chair for Network and Data Security.

You can find the latest release of our extension at: https://github.com/RUB-NDS/TLS-Attacker-BurpExtension/releases

TLS-Scanner

Thanks to the seamless integration of the TLS-Scanner into the BurpSuite, the penetration tester only needs to configure a single parameter: the host to be scanned. After clicking the Scan button, the extension runs the default checks and responds with a report that allows penetration testers to quickly determine potential issues in the server's TLS configuration. Basic tests check the supported cipher suites and protocol versions. In addition, several known attacks on TLS are automatically evaluated, including Bleichenbacher's attack, Padding Oracles, and Invalid Curve attacks.

Furthermore, the extension allows fine-tuning for the configuration of the underlying TLS-Scanner. The two parameters parallelProbes and overallThreads can be used to improve the scan performance (at the cost of increased network load and resource usage).

It is also possible to configure the granularity of the scan using Scan Detail and Danger Level. The level of detail contained in the returned scan report can also be controlled using the Report Detail setting.

Please refer to the GitHub repositories linked above for further details on configuration and usage of TLS-Scanner.

Scan History

If several hosts are scanned, the Scan History tab keeps track of the preformed scans and is a useful tool when comparing the results of subsequent scans.

Additional functions will follow in later versions

Currently, we are working on integrating an at-a-glance rating mechanism to allow for easily estimating the security of a scanned host's TLS configuration.

This is a combined work of Nurullah Erinola, Nils Engelbertz, David Herring, Juraj Somorovsky, Vladislav Mladenov, and Robert Merget. The research was supported by the European Commission through the FutureTrust project (grant 700542-Future-Trust-H2020-DS-2015-1).

If you would like to learn more about TLS, Juraj and Robert will give a TLS Training at Ruhrsec on the 27th of May 2019. There are still a few seats left.

Kali Linux 2018.3 Release - Penetration Testing And Ethical Hacking Linux Distribution

Kali 2018.3 brings the kernel up to version 4.17.0 and while 4.17.0 did not introduce many changes, 4.16.0 had a huge number of additions and improvements including more Spectre and Meltdown fixes, improved power management, and better GPU support.

New Tools and Tool Upgrades

Since our last release, we have added a number of new tools to the repositories, including:

idb – An iOS research / penetration testing tool
gdb-peda – Python Exploit Development Assistance for GDB
datasploit – OSINT Framework to perform various recon techniques
kerberoast – Kerberos assessment tools

In addition to these new packages, we have also upgraded a number of tools in our repos including aircrack-ng, burpsuite, openvas,wifite, and wpscan.
For the complete list of updates, fixes, and additions, please refer to the Kali Bug Tracker Changelog.

Download Kali Linux 2018.3

If you would like to check out this latest and greatest Kali release, you can find download links for ISOs and Torrents on the Kali Downloads page along with links to the Offensive Security virtual machine and ARM images, which have also been updated to 2018.3. If you already have a Kali installation you're happy with, you can easily upgrade in place as follows.

root@kali:~# apt update && apt -y full-upgrade

If you come across any bugs in Kali, please open a report on our bug tracker. It's more than a little challenging to fix what we don't know about.

Making sure you are up-to-date

To double check your version, first make sure your network repositories is enabled.

root@kali:~# cat</etc/apt/sources.list
deb http://http.kali.org/kali kali-rolling main non-free contrib
EOF
root@kali:~#

Then after running apt -y full-upgrade, you may require a reboot before checking:

root@kali:~# grep VERSION /etc/os-release
VERSION="2018.3"
VERSION_ID="2018.3"
root@kali:~#

Download Kali Linux 2018.3

How To Change Facebook’s Default Theme To Any Color You Want

Change Facebook Theme Using Chrome Extension

How To Change Facebook's Default Theme To Any Color You Want

We are going to share an interesting trick on changing your Facebook default theme. You just need a Google Chrome extension to perform this trick. If you are among me who feels very fatigued with the look of Facebook's by default theme then this is a must-see post because you will find out the easiest trick to make your facebook more attractive than before.

Facebook is a social networking site which empowers people to connect with friends and people around. That's how Facebook is habitually introduced. However, Facebook is beyond the need of being introduced as almost everyone is on it.

A couple of Days ago I was simply Surfing Google Chrome website and I somehow stumbled upon a Chrome Extension. Yes, a Chrome extension that will give your Facebook a Whole new look. I was apprehensive to try it, So I just installed it and checked my facebook. I was astonished to see my facebook homepage have all new look. I found it refreshing and decided to write steps on How to Change Facebook Themes using Chrome Extension.

How To Change Facebook's Default Theme To Any Color You Want

If You are among me who feels very fatigued with the look of Facebook's by default theme then this is a must-see post, Because you will find out the easiest trick to make your facebook more attractive than before. Simply follow the steps to know about it.

How to Change Facebook Theme Using Chrome Extension

Step 1. Install Stylish for Chrome from the Chrome Web Store. It will take hardly a minute to get installed in your Chrome browser.

Change Facebook Theme Using Chrome Extension

Step 2. Navigate to Facebook.com and click on the S button. Click on Find Styles for this Site to open a new tab with free themes to use for Facebook. Most of the themes are free and attractive too you can easily browse over the full website to discover your favorite theme.

Change Facebook Theme Using Chrome Extension

Step 3. Now You will be redirected towards https://userstyles.org Guess what! This site contains huge numbers of Facebook themes, One thing is for sure that you will be confused in-between what to select and which one to skip. Select any them and click on it. Now you will be given a full preview of your selected theme.

Change Facebook Theme Using Chrome Extension

Step 4. If everything is fine in the previewed theme, click on Install with Stylish button at the top right corner of the page. It will take few seconds or minutes depends on your theme size to be installed in Stylish Extension, once installed you will be notified with a success message.