Fristileaks 1.3 CTF Writeup

This vulnerable VM is a fun and simple CTF that can be downloaded from the awesome portal VulnHub.

Note: For vmware you may need to set the MAC address to 08:00:27:A5:A6:76 to get it working. I did, see Fig 1.

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Let’s get ready to rumble…

As I knew the IP address let’s launch an nmap scan. From the scan we can see only 1 open port (HTTP) and the robots.txt file with some folders.

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Let’s open the website.

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Nothing interesting so far. Now let’s try robots.txt

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In these folders we only find a picture of Jedi Obi-Wan Kenobi and nothing else.

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Giving some thought and this is the fristi game, we arrive to the following URL; a login/password admin portal.

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Let’s check the HTML source code, we can find that the image is encoded in Base64 and also a possible login name: eezeepz

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Looking more closely at the HTML source code we find another potential base64 encoded text.

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Let’s put the base64 encoded text into a decoder like Burp Proxy. We see a PNG header. Sounds like an image!

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Let’s write a Python script to obtain the image.

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Open the image and looks to me a password 

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So now we have a login and a password. Let’s continue!

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Great, we have log in into the portal.

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We can upload an image.

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Why not a webshell? :) I modify one of Kali webshells to set my IP address.

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Upload the webshell but an error happens. Some kind of filter!

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Let’s fire up Burp Proxy to bypass the filter, change the filename to add a png extension.

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Great, filter bypassed and we have a webshell uploaded.

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Let’s call our webshell

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Remember before calling the webshell to set up a Netcat listener! Awesome, we got shell :)

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Good place to start is checking the web app code, PHP in this case. In /var/ folder we can see a /fristigod/ folder by fristigod user, interesting.

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Poking around /var/www/ folder we find a notes.txt file.

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In /home/ folder we see several users.

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Moving to /eezeepz/ folder we find another notes.txt file with an interesting message. We can execute commands, great!

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Let’s execute a command so we can access /admin/ folder by using the /tmp/runthis file trick.

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Inside /admin/ folder we see a bunch of interesting files.

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We got some encrypted files and a Python script used to encrypt the files.

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Time for more Python scripting, let’s modify the encrypt script to decrypt the files.

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Now we have some passwords, let’s change our user to fristigod user. Remember one of the encrypted files was “whoisyourgodnow.txt”. We don’t have a real terminal so let’s get one, a good cheat sheet here.

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Moving to /fristigod/ folder reveals nothing.

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Recall in /var/ folder we had a /fristigod/ folder, let’s check that folder and we can find some interesting files, a root binary we can execute!

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Checking the .bash_history file we learn how to execute the previous root binary.

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Time to see the /root/ folder content by using the root binary we can execute.

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Jackpot! We got root shell and the Flag :)

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Kudos to the author for this fun CTF!

Did you get root shell and the Flag by using other tactics?

— Simon Roses Femerling / Twitter @simonroses

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Equation APT analysis using Security Data Science platform: BinSecSweeper

As many readers already know, at VULNEX we have been working on our BinSecSweeper project whose development began in 2013 thanks to an award by US DARPA within its pilot program Cyber Fast Track (CFT) and we were the only Spanish startup to win a research award. In May 2014 I was invited to The Pentagon by DARPA to present my project, together with the other CFT participants. It was a unique and awesome experience!

Since then BinSecSweeper has changed in every way possible due to a strong engineering effort. With the rise of so many APT, I thought it would be interesting to analyze using Data Science techniques a recent APT that has gained a lot of media coverage: Equation APT Group.

For this analysis, I have got 419 Windows executables of this APT that we will proceed to examine with BinSecSweeper, let’s look at the results!

In Fig. 1 we have the project dashboard and we can see a summary of the analysis. BinSecSweeper has identified malware and high-risk vulnerabilities establishing a severe threat level alert (based on the US Homeland Security System). It draws our attention to different characteristics of the executables such as Packers, Personal Identifiable Information and binary similarities.

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Fig. 1.

In metrics (Fig. 2) we see more details of the analysis, the metric that most interests us, at least to me, are the risks identified and the number of affected files. BinSecSweeper has identified interesting risks in this APT.

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Fig. 2.

In BinSecSweeper we can deepen the analysis of one, several or all files, but for this high-level analysis our current objective is to obtain the big picture. So let’s look at the analytics data, a very powerful tool, see Fig. 3.

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Fig. 3.

BinSecSweeper offers stunning graphics that help us to understand data very quickly and visually. In Fig. 4 we see a visualization of the entropy of the binaries. Most binaries are around 0.80 with some binaries in the 0.65 and 1.00 ranges.

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Fig. 4.

In Fig. 5 we can see the different types of binaries and should call our attention that most files are DLL and there is also one Driver, no doubt a file we should analyze in more detail.

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Fig. 5.

In Fig. 6 we see a very interesting metric, section names of the executables. It helps us to identify suspicious sections and packers.

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Fig. 6.

Fig. 7 is related to the previous metric, in this case we have the number of sections. There is a file with 10 sections.

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Fig. 7.

The following metric (Fig. 8) we have the number of imported libraries by the executables.

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Fig. 8.

Imported functions of the executables are interesting to understand functionality. In Fig. 9 we have this metric, specifically the Top 15 functions.

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Fig. 9.

We can also see the exported functions, Fig. 10.

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Fig. 10.

In Fig. 11 we see the identified compilers. It is interesting to understand the tools used by the APT authors.

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Fig. 11.

The last metric that we are going to see is the compilation timestamp of the executables organized by years. Clearly in 2008 the authors were very busy.

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Fig. 12.

Very quickly and easily we have obtained a good understanding of this APT without entering into complex/costly analysis or reverse engineering, which would be our next step.

Today, with millions of malware circulating and the complexity of software, it is necessary to have in our arsenal powerful analysis tools such as BinSecSweeper, which uses advanced Data Science techniques to analyze the security and privacy of software.

Perhaps it would be interesting to analyze all antivirus with BinSecSweeper ;)

Hasta la vista Baby, I’ll be back soon with more analysis 

For more information about BinSecSweeper you can contact us at BinSecSweeper@vulnex.com

Does your organization use Security Data Science? What would you like to analyze?

— Simon Roses Femerling / @simonroses

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A Security Breach Can Hurt You, More Than You Think!

Week after week we read about security breaches in top websites around the world, where millions of user’s data are exposed and the company not even reply with an apology. Until now nobody in management (your typical C-level) assumed any responsibility of the breach, many times due to lack of security, but this tendency is starting to change.

Some CEOs have step down due to high profile security breaches such as Target in 2014 and infamous Ashley Madison just recently, July 2015. Management needs to start speaking cybersecurity and assume responsibility of security breaches.

A security breach can really hurt you – take for example Ashley Madison attack. 36 millions of users data exposed – but let’s be honest, although many of these users were fake profiles, anyway many real users were still affected by the breach. The problem for Ashley Madison is not the attack itself but what has been reveled: the company had plans to go public but by examining the data it looks it was a scam, ouch.

Another recent high profile security breach has been Hacking Team, a security company that develops offensive solutions for LEA and has been selling their products to oppressive regimes worldwide. Hacking Team was a known company for a while of suspicious activities but was not confirmed until a security breach revealed 400 gigabytes of their data containing products source code, client contracts, emails, and much more, the dark side of this company. Really ouch!

MBA schools need to start including cybersecurity awareness into their courses so management understands the problems and how to deal with them. It is not enough to have a good CSO/CSIO these days; management needs to be involved 100%, if not a security breach could hurt your company.

Should high management be involved in cybersecurity matters?

— Simon Roses Femerling – @simonroses

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