Some months ago I analyzed some PDF exploits that I received via SPAM mails
. They contained the vulnerability CVE-2013-2729 leading to a ZeuS-P2P / Gameover sample. Back in June I received more PDF exploits, containing the same vulnerability, but in these cases it was a bit more difficult to extract the shellcode because the code was obfuscated. This is what we can see taking a look at the file account_doc~9345845757.pdf
(9cd2118e1a61faf68c37b2fa89fb970c) with peepdf
It seems that they used the same PDF exploit and they just added the obfuscation, because if we compare the peepdf output for the previous exploits we can see the same number of objects, same number of streams, same object ids, same id for the catalog, etc. After extracting the suspicious object (1) you can spot the shellcode easily, but some modifications are needed:
PPDF> object 1 > object1_output.txt
We can see two “images” encoded with Base64:
Submitted by jesparza on Thu, 2014/10/16 - 03:53
In mid-August I started receiving some emails from Yulia. She wanted me to take a look at her sweet ass:
I was not sure about it, but after receiving some more emails like this I took a look (I received the last one on the 10th of September). Then I found out that this was the beginning of a SmokeLoader campaign, I was really disappointed :( Out of spite, I started analyzing it ;p
These are some of the headers and the message body:
Date: Wed, 13 Aug 2014 12:55:56 -0400
From: "Yulia" <email@example.com>
Subject: My new photo
Hi it is Yulia fuck me ass at night. Look at my sweet ass on a photo I wait for you
I don't want to duplicate the information already published about this loader, so you can check the post published in July by StopMalvertising and what my colleague Michael Sandee said about it in 2012. Since then, SmokeLoader (known as Dofoil too) has modified the encryption to communicate with the C&C, added some extra plugins, etc.
After executing the binary you can easily spot that something is happening in your computer because you can see some strange POST requests to some known URLs. These URLs are extracted from the registry, opening the key Software\Microsoft\Windows\CurrentVersion\Uninstall and looking at the values of HelpLink and URLInfoAbout for the installed programs.
Submitted by jesparza on Sun, 2014/10/05 - 22:03
After some time without releasing any new version here is peepdf v0.3. It is not that I was not working in the project, but since the option to update the tool from the command line was released creating new versions became a secondary task. Besides this, since January 2014 Google removed the option to upload new downloads to the Google Code projects, so I had to figure out how to do it. From now on, all new releases will be hosted at eternal-todo.com, in the releases section.
The differences with version 0.2 are noticeable: new commands and features have been added, some libraries have been updated, detection for more vulnerabilities have been added, a lot of bug fixes, etc. This is the list of the most important changes (full changelog here):
Submitted by jesparza on Mon, 2014/06/16 - 19:38
I am used to receive SPAM emails containing zips and exes, even "PDF files" with double extension (.pdf.exe), but some days ago I received an email with a PDF file attached, without any .exe extension and it didn't look like a Viagra advertisement. Weird. I didn't have time to take a look at it, but the next day I received another one, with a different subject. The subject of the first email was “Invoice 454889 April” from Sue Mockridge (motherlandjjw949 at gmail.com) attaching “April invoice 819953.pdf” (eae0827f3801faa2a58b57850f8da9f5), and the second one “Image has been sent jesparza” from Evernote Service (message at evernote.com, but really protectoratesl9 at gmail.com) attaching “Agreemnet-81220097.pdf” (2a03ac24042fc35caa92c847638ca7c2).
At this point I was really curious so I took a look at them with peepdf.
Submitted by jesparza on Tue, 2014/05/20 - 23:51
One month ago I was trying to find a streaming site to watch a Spanish soccer match and I found futbolenvivoaldia.com. It was a redirection to the famous site Tarjeta Roja, but the interesting thing was that when I browsed the site with my mobile phone I saw the typical Antivirus scanner saying that my device was infected. Also, an app called “androidav_free.APK” (24f0a666a714e26c6c07ab407e37b112) was trying to be downloaded to my device.
The source of this fake page was one of the advertisement networks of the site tarjetaroja.eu, Mobicow. After some redirections and some tracking URLs this network was returning the following URL to the user's browser:
Taking a look at the script content we can see that it contains all the functions necessary to show the fake infection page to the user. Also, we can see that the following URL was used to download the app:
Submitted by jesparza on Mon, 2013/10/28 - 03:10
I was already missing these SPAM emails with some advice about my sexual life: “Your woman wants you to be the best lover”, “The greatest technique to gratify your lady”, etc. I was getting upset about this, I needed some help...;p
The result of the deobfuscation contains code to create a cookie (“visited_uq=55”) and also an iframe to load the URL hxxp://gylaqim.com/exit.php. This domain, created on the 21st of September, resolves each time to a different IP and has a history of more than 400 IPs. It has 6 authoritative DNS servers, ns*.gylaqim.com, also resolving to multiple IPs.
The initial pages seen until the moment are the following:
Submitted by jesparza on Tue, 2013/10/08 - 00:11
More than 2 years ago (that's a lot of time!) I published a simple Python script to monitor a Twitter account using Tweepy: basic account information, inactive friends and new/lost followers. But this script stopped working some time ago because Twitter updated its API to version 1.1. This update made obligatory using authentication to make any request and they also modified the request limits. Before the update, there was a limit of 150/350 requests per hour, depending on whether the request was authenticated or not, but now these limits are per request type and per 15 minutes. For example, to get a list of friends you can make a maximum of 15 requests per quarter of hour, but you can make other 15 to get a list of followers. If someone is late (like me) with the new API here you can find the full changelog.
Before starting to modify the code I had to update the Tweepy version too (2.1). The best and easiest way is using pip:
$ pip install tweepy
Submitted by jesparza on Sun, 2013/09/08 - 14:56
Some days ago I read the post about Joe Security's error when they analyzed an Andromeda sample and I also found new samples of this Trojan. Then I decided that I should write something about it. At least, just to remember some tricks of Andromeda for the next time and not starting from scratch. I'm Dory, I forget things ;)
When I analyzed this malware some months ago I thought that it was quite interesting due to the Anti-debugging and Anti-VM tricks it uses. You can also find references to the same malware with the name of Gamarue. It seems it is cool to rename the same malware with different names. Then you can find some families with three different names, like Cridex / Feodo / Bugat. Anyway, I also found these two links with very good and detailed information about analyzing Andromeda:
Submitted by jesparza on Sun, 2013/09/01 - 19:56
- Removing unnecessary HTML tags
- Find and replace eval functions with prints, for example, or hook the eval function if it is possible (PyV8)
- Beautify the code
- Find shellcodes and exploit URLs
- Repeat if necessary
Submitted by jesparza on Sun, 2013/08/18 - 22:14
BlackHat USA 2013 is here and tomorrow I will be explaining how to analyze exploit kits and PDF documents in my workshop “PDF Attack: From the Exploit Kit to the Shellcode” from 14:15 to 16:30 in the Florentine room. It will be really practical so bring your laptop and expect a practical session ;) All you need is a Linux distribution with pylibemu and PyV8 installed to join the party. You can run all on Windows too if you prefer.
Submitted by jesparza on Wed, 2013/07/31 - 12:40
Just some hours after the bombings during the Boston Marathon we already had several spam campaigns using that subject to infect users. It seems that cybercriminals don't respect anything, did we really expect something different? :p
On the past Wednesday I received four emails talking about the Boston incident. They were really suspicious, just a URL in the body, the URLs had just an IP instead of a good domain...I think someone was in a rush trying to profit from this as soon as possible, while it was still on the news...
The subjects were:
BREAKING - Boston Marathon Explosion
Explosion at the Boston Marathon
Aftermath to explosion at Boston Marathon
Explosions at the Boston Marathon
And the URLs I saw:
These URLs leaded to a simple webpage with six iframes. Five of them pointed to real videos about the tragedy and the other one redirected to a RedKit exploit kit which was trying to exploit a CVE-2012-1723 Java vulnerability (take a look at the vulnerability explanation). Also, a Meta Refresh Tag was leading to this URL:
Submitted by jesparza on Sun, 2013/04/21 - 21:50
After lunch it was Sergey Bratus and Travis Goodspeed's turn to speak about the security of USB ports
, telling how it is possible to compromise the whole system via a unattended USB port. This was a really interesting talk that one can explore by himself taking a look at some good documentation on Travis' blog
The talk “We Came In Peace – They Don’t: Hackers vs. CyberWar”
was next. He gave his opinion about the actual cyberwarfare and the difference between the point of view of Governments and cybersecurity experts about this subject. Some ideas from his talk: avoid the use of 0-days as weapons through Full-Disclosure, learn how to protect you playing CTFs and don't give up.
Submitted by jesparza on Sun, 2013/04/07 - 14:16
Until now I had not had enough time to write about my experience at my first Troopers
. Due to some good comments about it
I had had in mind going to Troopers since some time ago, but for one reason or another I hadn't been able to do it. Last year I had the opportunity to share table with Enno Rey, Troopers
organizer and CEO of ERNW
, at BlackHat Europe. That time I saw they were a good team and good people, and this year, living closer to Heidelberg, I had no excuses to go.
I arrived in Heidelberg at 3:30AM after 9 hours on the road due to the bad weather conditions. I was able to rest to be ready for the talks
in the next morning. I missed the keynote by Rodrigo Branco
, but I heard that it was really good. The first talk I attended was “Paparazzi over IP”
by Daniel Mende and Pascal Turbing about hacking a CANON camera, equipped with a wireless adapter and other features. The result was that it was possible to see all the photographs taken, control the device remotely and intercept the images while they were about to be sent to a cloud storage.
Submitted by jesparza on Sun, 2013/04/07 - 13:52
After reading the Eurograbber report and taking into account that there were a lot of similarities with Sopelka Botnet, which I had analyzed some months before
, I decided to write a blog post about it
. At the same moment, the Rooted CON CFP was closing, so I submitted this subject and then I forced myself to research further to demonstrate that Eurograbber was just a hype. Thanks to the investigations by S21sec
there was more than enough information.
Submitted by jesparza on Mon, 2013/04/01 - 21:25