Saturday, July 21, 2018

Recovering data from an old encrypted Time Machine backup

Recovering data from a backup should be an easy thing to do. At least this is what you expect. Yesterday I had a problem which should have been easy to solve, but it was not. I hope this blog post can help others who face the same problem.


The problem

1. I had an encrypted Time Machine backup which was not used for months
2. This backup was not on an official Apple Time Capsule or on a USB HDD, but on a WD MyCloud NAS
3. I needed files from this backup
4. After running out of time I only had SSH access to the macOS, no GUI

The struggle

By default, Time Machine is one of the best and easiest backup solution I have seen. As long as you stick to the default use case, where you have one active backup disk, life is pink and happy. But this was not my case.

As always, I started to Google what shall I do. One of the first options recommended that I add the backup disk to Time Machine, and it will automagically show the backup snapshots from the old backup. Instead of this, it did not show the old snapshots, but started to create a new backup. Panic button has been pressed, backup cancelled, back to Google.


Another tutorials recommend to click on the Time Machine icon and pressing alt (Option) key, where I can choose "Browse other backup disks". But this did not list the old Time Machine backup. It did list the backup when selecting disks in Time Machine preferences, but I already tried and failed that way.


YAT (yet another tutorial) recommended to SSH into the NAS, and browse the backup disk, as it is just a simple directory where I can see all the files. But all the files inside where just bunch of nonsense, no real directory structure.

YAT (yet another tutorial) recommended that I can just easily browse the content of the backup from the Finder by double clicking on the sparse bundle file. After clicking on it, I can see the disk image on the left part of Finder, attached as a new disk.
Well, this is true, but because of some bug, when you connect to the Time Capsule, you don't see the sparse bundle file. And I got inconsistent results, for the WD NAS, double clicking on the sparse bundle did nothing. For the Time Capsule, it did work.
At this point, I had to leave the location where the backup was present, and I only had remote SSH access. You know, if you can't solve a problem, let's complicate things by restrict yourself in solutions.

Finally I tried to check out some data forensics blogs, and besides some expensive tools, I could find the solution.

The solution

Finally a blog post provided the real solution - hdiutil.
Best part of hdiutil is that you can provide the readonly flag to it. This can be very awesome when it comes to forensics acquisition.


To mount any NAS via SMB:
mount_smbfs afp://<username>@<NAS_IP>/<Share_for_backup> /<mountpoint>

To mount a Time Capsule share via AFP:
mount_afp afp://any_username:password@<Time_Capsule_IP>/<Share_for_backup> /<mountpoint>

And finally this command should do the job:
hdiutil attach test.sparsebundle -readonly

It is nice that you can provide readonly parameter.

If the backup was encrypted and you don't want to provide the password in a password prompt, use the following:
printf '%s' 'CorrectHorseBatteryStaple' | hdiutil attach test.sparsebundle -stdinpass -readonly

Note: if you receive  error "resource temporary unavailable", probably another machine is backing up to the device

And now, you can find your backup disk under /Volumes. Happy restoring!

Probably it would have been quicker to either enable the remote GUI, or to physically travel to the system and login locally, but that would spoil the fun.

Tuesday, March 20, 2018

Workshop and Presentation Slides and Materials

All of our previous workshop and presentation slides and materials are available in one location, from Google Drive.

From now on, we are only going to keep the latest-greatest version of each talk/workshop and announce changes on Twitter.

Friday, May 19, 2017

Pcap of Wannacry Spreading Using EthernalBlue

Saw that a lot of people were looking for a pcap with WannaCry spreading Using EthernalBlue.

I have put together a little "petri dish" test environment and started looking for a sample that has the exploit. Some samples out there simply do not have the exploit code, and even tough they will encrypt the files locally, sometimes the mounted shares too, they would not spread.

Luckily, I have found this nice blog post from McAfee Labs: https://securingtomorrow.mcafee.com/mcafee-labs/analysis-wannacry-ransomware/ with the reference to the sample SHA256: 24d004a104d4d54034dbcffc2a4b19a11f39008a575aa614ea04703480b1022c (they keep referring to samples with MD5, which is still a very-very bad practice, but the hash is MD5: DB349B97C37D22F5EA1D1841E3C89EB4)

Once I got the sample from the VxStream Sandbox site, dropped it in the test environment, and monitored it with Security Onion. I was super happy to see it spreading, despite the fact that for the first run my Windows 7 x64 VM went to BSOD as the EthernalBlue exploit failed.

But the second run was a full success, all my Windows 7 VMs got infected. Brad was so kind and made a guest blog post at one of my favorite sites, www.malware-traffic-analysis.net so you can find the pcap, description of the test environment and some screenshots here: http://malware-traffic-analysis.net/2017/05/18/index2.html

Monday, October 17, 2016

Why (I believe) WADA was not hacked by the Russians

Disclaimer: This is my personal opinion. I am not an expert in attribution. But as it turns out, not many people in the world are good at attribution. I know this post lacks real evidence, and is mostly based on speculation.



Let's start with the main facts we know about the WADA hack, in a chronological order:


1. Some point in time (August - September 2016), the WADA database has been hacked and exfiltrated
2. August 15th, "WADA has alerted their stakeholders that email phishing scams are being reported in connection with WADA and therefore asks its recipients to be careful"  https://m.paralympic.org/news/wada-warns-stakeholders-phishing-scams
3.September 1st, the fancybear.net domain has been registered
   Domain Name: FANCYBEAR.NET
   ...
   Updated Date: 18-sep-2016
   Creation Date: 01-sep-2016

4. The content of the WADA hack has been published on the website
5. The @FancyBears and @FancyBearsHT Twitter accounts have been created, and started to tweet on 12th September, reaching out to journalists
6. 12th September, Western media started headlines "Russia hacked WADA"
7. The leaked documents have been altered, states WADA https://www.wada-ama.org/en/media/news/2016-10/cyber-security-update-wadas-incident-response


The Threatconnect analysis

The only technical analysis on why Russia was behind the hack, can be read here: https://www.threatconnect.com/blog/fancy-bear-anti-doping-agency-phishing/

After reading this, I was able to collect the following main points:

  1. It is Russia, because Russian APT groups are capable of phishing
  2. It is Russia, because the phishing site "wada-awa[.]org was registered and uses a name server from ITitch[.]com, a domain registrar that FANCY BEAR actors recently used"
  3. It is Russia, because "Wada-arna[.]org and tas-cass[.]org were registered through and use name servers from Domains4bitcoins[.]com, a registrar that has also been associated with FANCY BEAR activity."
  4. It is Russia, because "The registration of these domains on August 3rd and 8th, 2016 are consistent with the timeline in which the WADA recommended banning all Russian athletes from the Olympic and Paralympic games."
  5. It is Russia, because "The use of 1&1 mail.com webmail addresses to register domains matches a TTP we previously identified for FANCY BEAR actors."

There is an interesting side-track in the article, the case of the @anpoland account. Let me deal with this at the end of this post.

My problem with the above points is that all five flag was publicly accessible to anyone as TTP's for Fancy Bear. And meanwhile, all five is weak evidence. Any script kittie in the world is capable of both hacking WADA, and planting these false-flags.

A stronger than these weak evidences would be:

  • Malware sharing same code attributed to Fancy Bear (where the code is not publicly available or circulating on hackforums)
  • Private servers sharing IP address with previous attacks attributed to Fancy Bear (where the server is not a hacked server, or a proxy used by multiple parties)
  • E-mail addresses used to register the domain attributed to Fancy Bear
  • Many other things
For me it is quite strange that after such great analysis on Guccifer 2.0, the Threatconnect guys came up with this low-value post. 


The fancybear website

It is quite unfortunate that the analysis was not updated after the documents have been leaked. But let's just have a look at the fancybear . net website, shall we?

Now the question is, if you are a Russian state sponsored hacker group, and you are already accused of the hack itself, do you create a website with tons of bears on the website, and do you choose the same name (Fancy Bear) for your "Hack team" that is already used by Crowdstrike to refer to a Russian state sponsored hacker group? Well, for me, it makes no sense. Now I can hear people screaming: "The Russians changed tactics to confuse us". Again, it makes no sense to change tactics on this, while keeping tactics on the "evidence" found by Threatconnect.

It makes sense that a Russian state sponsored group creates a fake persona, names it Guccifer 2.0, pretends Guccifer 2.0 is from Romania, but at the end it turns out Guccifer 2.0 isn't a native Romanian speaker. That really makes sense.

What happens when someone creates this fancybear website for leaking the docs, and from the Twitter account reaches out to the media? Journalists check the website, they see it was done by Fancy Bear, they Bing Google this name, and clearly see it is a Russian state sponsored hacker group. Some journalists also found the Threatconnect report, which seems very convincing for the first read. I mean, it is a work of experts, right? So you can write in the headlines that the hack was done by the Russians.

Just imagine an expert in the USA or Canada writing in report for WADA:
"the hack was done by non-Russian, but state-sponsored actors, who planted a lot of false-flags to accuse the Russians and to destroy confidence in past and future leaks". Well, I am sure this is not a popular opinion, and whoever tries this, risks his career. Experts are human, subject to all kind of bias.

The Guardian

The only other source I was able to find is from The Guardian, where not just one side (it was Russia) was represented in the article. It is quite unfortunate that both experts are from Russia - so people from USA will call them being not objective on the matter. But the fact that they are Russian experts does not mean they are not true ...

https://www.theguardian.com/sport/2016/sep/15/fancy-bears-hackers--russia-wada-tues-leaks

Sergei Nikitin:
“We don’t have this in the case of the DNC and Wada hacks, so it’s not clear on what basis conclusions are being drawn that Russian hackers or special services were involved. It’s done on the basis of the website design, which is absurd,” he said, referring to the depiction of symbolically Russian animals, brown and white bears, on the “Fancy Bears’ Hack Team” website.

I don't agree on the DNC part, but this is not the topic of conversation here.

Alexander Baranov:
"the hackers were most likely amateurs who published a “semi-finished product” rather than truly compromising information. “They could have done this more harshly and suddenly,” he said. “If it was [state-sponsored] hackers, they would have dug deeper. Since it’s enthusiasts, amateurs, they got what they got and went public with it.”"

The @anpoland side-track

First please check the tas-cas.org hack https://www.youtube.com/watch?v=day5Aq0bHsA  , I will be here when you finished it. This is a website for "Court of Arbitration for Sport’s", and referring to the Threatconnect post, "CAS is a the highest international tribunal that was established to settle disputes related to sport through arbitration. Starting in 2016, an anti-doping division of CAS began judging doping cases at the Olympic Games, replacing the IOC disciplinary commission." Now you can see why this attack is also discussed here.


  • My bet is that this machine was set-up for these @anpoland videos only. Whether google.ru is a false flag or it is real, hard to decide. It is interesting to see that there is no google search done via google.ru, it is used only once. 
  • The creator of the video can't double click. Is it because he has a malfunctioning mouse? Is it because he uses a virtualization console, which is near-perfect OPSEC to hide your real identity? My personal experience is that using virtualization consoles remotely (e.g. RDP) have very similar effects what we can see on the video. 
  • The timeline of the Twitter account is quite strange, registered in 2010
  • I agree with the Threatconnect analysis that this @anpoland account is probably a faketivist, and not an activist. But who is behind it, remains a mistery. 
  • Either the "activist" is using a whonix-like setup for remaining anonymous, or a TOR router (something like this), or does not care about privacy at all. Looking at the response times (SQLmap, web browser), I doubt this "activist" is behind anything related to TOR. Which makes no sense for an activist, who publishes his hack on Youtube. People are stupid for sure, but this does not add up. It makes sense that this was a server (paid by bitcoins or stolen credit cards or whatever) rather than a home computer.
For me this whole @anpoland thing makes no sense, and I think it is just loosely connected to the WADA hack. 

The mysterious Korean characters in the HTML source

There is another interesting flag in the whole story, which actually makes no sense. When the website was published, there were Korean characters in HTML comments. 



When someone pointed this out in Twitter, these Korean HTML comments disappeared:
These HTML comments look like generated HTML comments, from a WYSIWYG editor, which is using Korean language. Let me know if you can identify editor.

The Russians are denying it

Well, what choice they have? Does not matter if they did this or not, they will deny it. And they can't deny this differently. Just imagine a spokeperson: "Previously we have falsely denied the DCC and DNC hacks, but this time please believe us, this wasn't Russia." Sounds plausible ...

Attribution

Let me sum up what we know:

It makes sense that the WADA hack was done by Russia, because:

  1. Russia being almost banned from the Olympics due to doping scandal, it made sense to discredit WADA and US olympians
  2. There are multiple(weak) evidences which point to Russia
It makes sense that the WADA hack was not done by  Russia, because: 
  1. By instantly attributing the hack to the Russians, the story was more about to discredit Russia than discrediting WADA or US Olympians.
  2. In reality, there was no gain for Russia for disclosing the documents. Nothing happened, nothing changed, no discredit for WADA. Not a single case turned out to be illegal or unethical.
  3. Altering the leaked documents makes no sense if it was Russia (see update at the end). Altering the leaked documents makes a lot of sense if it was not Russia. Because from now on, people can always state "these leaks cannot be trusted, so it is not true what is written there". It is quite cozy for any US organization, who has been hacked or will be hacked. If you are interested in the "Russians forging leaked documents" debate, I highly recommend to start with this The Intercept article
  4. If the Korean characters were false flags planted by the Russians, why would they remove it? If it had been Russian characters, I would understand removing it.
  5. All evidence against Russia is weak, can be easily forged by even any script kittie.

I don't like guessing, but here is my guess. This WADA hack was an operation of a (non-professional) hackers-for-hire service, paid by an enemy of Russia. The goal was to hack WADA, leak the documents, modify some contents in the documents, and blame it all on the Russians ...

Questions and answers

  • Was Russia capable of doing this WADA hack? Yes.
  • Was Russia hacking WADA? Maybe yes, maybe not.
  • Was this leak done by a Russian state-sponsored hacker group? I highly doubt that.
  • Is it possible to buy an attribution-dice where all six-side is Russia? No, it is sold-out. 

To quote Patrick Gray: "Russia is the new China, and the Russians ate my homework."©

Let me know what you think about this, and please comment. 

Sunday, June 19, 2016

CSRF Referer header strip

Intro

Most of the web applications I see are kinda binary when it comes to CSRF protection; either they have one implemented using CSRF tokens (and more-or-less covering the different functions of the web application) or there is no protection at all. Usually, it is the latter case. However, from time to time I see application checking the Referer HTTP header.

A couple months ago I had to deal with an application that was checking the Referer as a CSRF prevention mechanism, but when this header was stripped from the request, the CSRF PoC worked. BTW it is common practice to accept empty Referer, mainly to avoid breaking functionality.

The OWASP Cross-Site Request Forgery (CSRF) Prevention Cheat Sheet tells us that this defense approach is a baaad omen, but finding a universal and simple solution on the Internetz to strip the Referer header took somewhat more time than I expected, so I decided that the stuff that I found might be useful for others too.

Solutions for Referer header strip

Most of the techniques I have found were way too complicated for my taste. For example, when I start reading a blog post from Egor Homakov to find a solution to a problem, I know that I am going to:
  1. learn something very cool;
  2. have a serious headache from all the new info at the end.
This blog post from him is a bit lighter and covers some useful theoretical background, so make sure you read that first before you continue reading this post. He shows a few nice tricks to strip the Referer, but I was wondering; maybe there is an easier way?

Rich Lundeen (aka WebstersProdigy) made an excellent blog post on stripping the Referer header (again, make sure you read that one first before you continue). The HTTPS to HTTP trick is probably the most well-known one, general and easy enough, but it quickly fails the moment you have an application that only runs over HTTPS (this was my case).

The data method is not browser independent but the about:blank trick works well for some simple requests. Unfortunately, in my case the request I had to attack with CSRF was too complex and I wanted to use XMLHttpRequest. He mentions that in theory, there is anonymous flag for CORS, but he could not get it work. I also tried it, but... it did not work for me either.

Krzysztof Kotowicz also wrote a blog post on Referer strip, coming to similar conclusions as Rich Lundeen, mostly using the data method.

Finally, I bumped into Johannes Ullrich's ISC diary on Referer header and that led to me W3C's Referrer Policy. So just to make a dumb little PoC and show that relying on Referer is a not a good idea, you can simply use the "referrer" meta tag (yes, that is two "r"-s there).

The PoC would look something like this:
<html>
  <meta name="referrer" content="never">
  <body>
    <form action="https://vistimsite.com/function" method="POST">
      <input type="hidden" name="param1" value="1" />
      <input type="hidden" name="param2" value="2" />
      ...
    </form>
    <script>
      document.forms[0].submit();
    </script>
  </body>
</html>

Conclusion

As you can see, there is quite a lot of ways to strip the Referer HTTP header from the request, so it really should not be considered a good defense against CSRF. My preferred way to make is PoC is with the meta tag, but hey, if you got any better solution for this, use the comment field down there and let me know! :)