Éramos del Masie en 2006-2007

Alumnos Master

1. Overview

Is an elf32 static and stripped binary, but the good news is that it was compiled with gcc and it will not have shitty runtimes and libs to fingerprint, just the libc ... and libprhrhead
This binary is writed by Ricardo J Rodrigez

When it's executed, it seems that is computing the flag:

But this process never ends .... let's see what strace say:

There is a thread deadlock, maybe the start point can be looking in IDA the xrefs of 0x403a85
Maybe we can think about an encrypted flag that is not decrypting because of the lock.

This can be solved in two ways:

static: understanding the cryptosystem and programming our own decryptor
dynamic: fixing the the binary and running it (hard: antidebug, futex, rands ...)

At first sight I thought that dynamic approach were quicker, but it turned more complex than the static approach.

2. Static approach

Crawling the xrefs to the futex, it is possible to locate the main:

With libc/libpthread function fingerprinting or a bit of manual work, we have the symbols, here is the main, where 255 threads are created and joined, when the threads end, the xor key is calculated and it calls the print_flag:

The code of the thread is passed to the libc_pthread_create, IDA recognize this area as data but can be selected as code and function.

This is the thread code decompiled, where we can observe two infinite loops for ptrace detection and preload (although is static) this antidebug/antihook are easy to detect at this point.

we have to observe the important thing, is the key random?? well, with the same seed the random sequence will be the same, then the key is "hidden" in the predictability of the random.

If the threads are not executed on the creation order, the key will be wrong because is xored with the th_id which is the identify of current thread.

The print_key function, do the xor between the key and the flag_cyphertext byte by byte.

And here we have the seed and the first bytes of the cypher-text:

With radare we can convert this to a c variable quickly:

And here is the flag cyphertext:

And with some radare magics, we have the c initialized array:

radare, is full featured :)

With a bit of rand() calibration here is the solution ...

The code:
https://github.com/NocONName/CTF_NcN2k15/blob/master/theAnswer/solution.c

3. The Dynamic Approach

First we have to patch the anti-debugs, on beginning of the thread there is two evident anti-debugs (well anti preload hook and anti ptrace debugging) the infinite loop also makes the anti-debug more evident:

There are also a third anti-debug, a bit more silent, if detects a debugger trough the first available descriptor, and here comes the fucking part, don't crash the execution, the execution continues but the seed is modified a bit, then the decryption key will not be ok.

Ok, the seed is incremented by one, this could be a normal program feature, but this is only triggered if the fileno(open("/","r")) > 3 this is a well known anti-debug, that also can be seen from a traced execution.

Ok, just one byte patch, seed+=1 to seed+=0, (add eax, 1 to add eax, 0)

before:

after:

To patch the two infinite loops, just nop the two bytes of each jmp $-0

Ok, but repairing this binary is harder than building a decryptor, we need to fix more things:

The sleep(randInt(1,3)) of the beginning of the thread to execute the threads in the correct order
Modify the pthread_cond_wait to avoid the futex()
We also need to calibrate de rand() to get the key (just patch the sleep and add other rand() before the pthread_create loop

Adding the extra rand() can be done with a patch because from gdb is not possible to make a call rand() in this binary.

With this modifications, the binary will print the key by itself.

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Alumnos Master

Hi everyone,

Great news! I will be mentoring SANS 575: Mobile Device Security and Ethical Hacking in Luxembourg on Thursday evenings 18:00-20:00, starting from January 15, 2015.

Mentor classes are special, 10 week-format SANS classroom sessions that give the students time to absorb and master the same material with the guidance of a trained security professional.

Students receive all the same course materials used at SANS conferences and study at a more leisurely pace, so students will have:

Hardcopy set of SANS course books
Mentor Program study materials
Weekly Mentor led sessions

Prior to the weekly Mentor-led classroom sessions, students study SANS course material at their own pace. Each week, students meet with other professionals in their hometown area and the SANS mentor, who leads topical discussions pointing out the most salient features of the weekly material studied, provides hands-on demonstrations, and answer questions. The Mentor's goal is to help student's grasp the more difficult material, master the exercises, demonstrate the tools and prepare for GIAC certification.

On SANS SEC575, we will learn about mobile device infrastructures, policies and management, we will see the security models of the different platforms, like the data storage and file system architecture. We will also see how to unlock, root and jailbreak mobile devices in order to prepare them for data extraction and further testing. In the second half of the course, we will learn how to perform static and dynamic mobile application analysis, the usage of automated application analysis tools and how to manipulate application behavior. Last but not least, we will see how to perform mobile penetration testing that includes fingerprinting mobile devices, wireless network probing and scanning, attacking wireless infrastructures, using network manipulation attacks and attacks against mobile applications and back-end applications.

For more info, here is the link for the class: http://www.sans.org/mentor/class/sec575-luxembourg-15jan2015-david-szili
My Mentor bio: http://www.sans.org/mentor/bios#david-szili

Information on the class, special discounts and applying for the class: szili_(dot)_david_(at)_hotmail_(dot)_com

Additional info can be also found at: https://www.sans.org/mentor

Some special price is also available for this course. A few examples: http://www.sans.org/mentor/specials

Best regards,

David

Such low price. Very SANS. Much learning. Wow!

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Alumnos Master

I get emails from readers asking for specific malware samples and thought I would make a mini post about it.

Yes, I often obtain samples from various sources for my own research.

I am sometimes too lazy/busy to post them but don't mind sharing.
If you are looking for a particular sample, feel free to ask. I might have it.

Send MD5 (several or few samples). I cannot provide hundreds/thousands of samples or any kind of feeds. If you ask for a particular family, I might be able to help if I already have it.

Unfortunately, I do not have time to do homework for students and provide very specific sets for malware with specific features as well as guarantee the C2s are still active. Send your MD5(s) or at least malware family and I check if I have it :) If i have it, I will either send you or will post on the blog where you can download.

If you emailed me in the past and never got an answer, please remind me. Sometimes emails are long with many questions and I flag them to reply to later, when I have time and they get buried or I forget. It does not happen very often but accept my apologies if it happened to you.

Before you ask, check if it is already available via Contagio or Contagio Mobile.
1. Search the blog using the search box on the right side
2. Search here https://www.mediafire.com/folder/b8xxm22zrrqm4/BADINFECT
3. Search here https://www.mediafire.com/folder/c2az029ch6cke/TRAFFIC_PATTERNS_COLLECTION
4. Search here https://www.mediafire.com/folder/78npy8h7h0g9y/MOBILEMALWARE

Cheers, Mila

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Alumnos Master

Intro:
I recently returned from the new Social Engineering training provided by Social-Engineer.org in the beautiful city of Seattle,WA, a state known for sparkly vampires, music and coffee shop culture. As many of you reading this article, i also read the authors definitive book Social Engineering- The art of human hacking and routinely perform SE engagements for my clients. When i heard that the author of the aforementioned book was providing training i immediately signed up to get an in person glance at the content provided in the book. However, i was pleasantly surprised to find the course covered so much more then what was presented in the book.

Instructors:

Chris Hadnagy the author of the book Social Engineering- The art of human hacking.
Robin Dreeke the author of the book It's not all about me.

I wasn't aware that there would be more then one instructor and was extremely happy with the content provided by both instructors. Chris and Robin both have a vast amount of knowledge and experience in the realm of social engineering. Each instructor brought a different angle and use case scenario to the course content. Robin is an FBI agent in charge of behavioral analysis and uses social engineering in his daily life and work to get the results needed to keep our country safe. Chris uses social engineering in his daily work to help keep his clients secure and provides all sorts of free learning material to the information security community through podcasts and online frameworks.

Course Material and Expectation:
I originally thought that the material covered in class would be a live reiteration of the material covered in Chris's book. However, I couldn't have been more wrong !! The whole first day was about reading yourself and other people, much of the material was what Robin uses to train FBI agents in eliciting information from possible terrorist threats. Each learning module was based on live demo's, nightly labs, and constant classroom interaction. Each module was in depth and the level of interaction between students was extremely useful and friendly. I would say the instructors had as much fun as the students learning and sharing social techniques and war stories.
The class was heavily made up of ways to elicit personal and confidential information in a way that left the individuatial "Happier for having met you". Using language, body posture and social truisms as your weapon to gather information, not intended for your ears, but happily leaving the tongue of your target.
Other class activities and materials included an in depth look at micro expressions with labs and free extended learning material going beyond the allotted classroom days. Also break out sessions which focused on creating Phone and Phishing scripts to effectively raise your rate of success. These sessions were invaluable at learning to use proper language techniques on the phone and in email to obtain your objectives.

Nightly Missions/Labs:
If you think that you are going to relax at night with a beer. Think again!! You must ensure that your nights are free, as you will be going on missions to gain information from live targets at venues of your choice. Each night you will have a partner and a mission to gain certain information while making that persons day better then it started. The information you are requested to obtain will change each night and if done properly you will notice all of the material in class starting to unfold.. When you get to body language training you will notice which targets are open and when its best to go in for the kill. You will see interactions change based on a persons change in posture and facial expressions. Each day you will take the new techniques you have learned and put them into practice. Each morning you have to report your findings to the class..
During my nightly labs i obtained information such as door codes to secured research facilities, information regarding secret yet to be released projects. On the lighter side of things i obtained much personal information from my targets along with phone numbers and invitations for further hangouts and events. I made many new friends inside and outside of class.
There were also labs within the confines of the classroom such as games used to solidify your knowledge and tests to figure out what kind of learner you are. Technical labs on the use of information gathering tools and ways to use phone and phishing techniques to your advantage via linguistically and technologically. Essentially the class was about 60% interaction and labs.

Proof it works:
After class i immediately had a phishing and phone based contract at my current employment. I used the email and phone scripts that we created in class with 100% click rate and 100% success in phone elicitation techniques. Gaining full unfettered access to networks through phone and email elicitation and interaction. Although I do generally have a decent SE success rate, my rates on return are now much higher and an understanding of what works and what doesn't, and why are much more refined.

Conclusion and Certification:
I paid for this class out of pocket, including all expenses, hotels, rentals cars and planes etc etc. I would say that the class was worth every penny in which i paid for it. Many extras were given including black hat passes, extended training from notable sources and continued interaction from instructors after class ended. I would highly recommend this class to anyone looking for a solid foundation in social engineering or a non technical alternative to training. You will learn a lot, push yourself in new ways and have a blast doing it. However I did not see any sparkly vampires while in seattle.... Twilight lied to me LOL
The certification is a 48 hour test in which you will utilize your knowledge gained technologically and socially to breach a company.I am not going to give away to much information about the certification as i haven't taken it yet and I do not want to misspeak on the subject. However I will say that social-engineer.org has done an excellent job at figuring out a way to include Real World Social Engineering into a test with verifiable proof of results. I am going to take my test in a couple weeks and it should be a blast!!!

Thanks and I hope this review is helpful to all those looking for SE training. I had a blast :) :)

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