Saturday, November 4, 2017

CrunchyRoll hack delivers malware


There's a Reddit post today with a PSA (Public Service Announcement) about Crunchyroll, a website that offers anime streaming, being hacked:

PSA : Don't enter at the moment, it seems they've been hacked.

As mentioned before, Crunchyroll offers anime streaming, and in their own words:
Enjoy your favorite anime & manga at the speed of Japan

The German Crunchyroll team has additionally issued the following warning:

The official CrunchyRoll Twitter account has tweeted the following:

If you are only interested in how to remove this malware, scroll down to the disinfection/removal section, or click here.

Update:  CrunchyRoll has announced, after a few hours, that the issue is resolved:

However, I still advise you to scroll over to the disinfection or removal section. Any questions, feel free to leave a comment, or contact me on Twitter.


So, what happens when you visit the CrunchyRoll website? Curently, you get a message the website has encountered an error:

Figure 1 - CrunchyRoll error page

Earlier today, the CrunchyRoll website was showing the following:

Figure 2 - Likely hacked CrunchyRoll website (Image source)

While the CrunchyRoll team claims it was a DNS hijack, I have (so far) found no evidence as to the validity of this claim, and it rather appears someone was able to hack the website.

Either way, while this is bad, CrunchyRoll took swift action by taking down the website, and an investigation is under way.

What happens if you click the 'Download now' button? A new file, called CrunchyViewer.exe, will be downloaded from the following IP address:


This IP appears to have hosted fake antivirus software or similar in the past:

Figure 3 - Older resolutions (2010)

The newly download file is seemingly the legitimate CrunchyViewer or Crunchyroll, but, near the end of the file, there is a chunk of Base64 encoded data appended, as seen in Figure 4:

Figure 4 - base64 encoded data (click to enlarge)

Using a Base64 decoder, we get a new file, called svchost.exe. This binary will place a copy of itself in the current user's %appdata%\roaming folder, for example:


This file will periodically call to its C2, or command-and-control server, and wait for any commands:


Currently, it does not appear the C2 responds on that specific port (6969), however, it is online.

There are claims the malware will additionally install ransomware - I have not observed this behaviour, but it is definitely possible once the C2 sends back (any) commands. More likely, it is a form of keylogger - malware that can record anything you type, and send it back to the attacker.

Update: It appears however, thanks to ANY.RUN for the heads-up, (analysis here) that the malware actually downloads Meterpreter, which is a default Metasploit payload.

More information about Meterpreter can be found here, but basically, it can be viewed as a backdoor, as it allows the attacker to completely control your machine. However, it does appear the C2 server only downloaded Meterpreter for a limited amount of time - as port 6969 only responded within a specific time-frame.

Note that the disinfection or removal tips are still applicable in this case.

Svchost.exe will also create an autorun entry:

Figure 5 - newly created run key (click to enlarge)

This basically means the malware will start every time you (re)boot or restart the machine.

Just for fun, it appear that the miscreant's name, or the person responsible for creating the malware is named Ben, as appears from the debug paths:


Taiga is 'A lightweight anime tracker for Windows'. This does not mean they are involved, but rather that 'Ben' has decided to include Taiga in the package.

Update: the developer of Taiga has included a fix for 'CrunchyViewer':

Thus, if you now update or install the official Taiga application, it will prompt you if the malware is found, and is able to remove it.


Disinfection is rather straightforward:

  • Remove the malicious "Java" Run key, by opening Regedit, and browsing to:
  • Delete the 'Java' key;
  • Reboot your machine;
  • Remove the malicious binary, by navigating to:
    %appdata%\Roaming (for exampleC:\Users\Yourusername\AppData\Roaming\)
  • Delete the 'svchost.exe' file.
  • Perform a scan with your installed antivirus product;
  • Perform a scan with an online antivirus, which is different from the one you have. Alternatively, perform a scan with Malwarebytes.
  • Change all your passwords if possible. Better be safe than sorry.


Prevention  advise in general, which also pertains to CrunchyRoll's compromise:

  • Install an antivirus;
  • Keep your browser up-to-date;
  • Install NoScript if you have Firefox;
  • Install a 'well-rounded' ad-blocker, for example uBlock Origin (works with most browsers);
  • If a website you visit frequently suddenly looks completely different, or urges you to download whatever, be safe rather than sorry, and leave the website.
  • Additionally, try to Google or use social media to verify if anyone else is experiencing the same issue.
In this particular case or incident, you may also want to block the two IP addresses as described in this blog post, by adding them in your firewall, or adding them in your hosts file, like so:

For more information on how to do that, read:
How to Edit Your Hosts File on Windows, Mac, or Linux

Note that there needs to be at least a space between, and the address you want to block.


This hack shows that any website or organisation is, in theory, vulnerable to someone hijacking the website, and consequently download and install malware on a user's machine.

While it is uncertain what exactly happened, CrunchyRoll took correct action by taking the website down not too long after. At this point, it is best to monitor their Twitter account, and/or wait for an official statement.

If you have not executed the file, you should be safe. Simply delete the downloaded file.

Note that I can't speak for any second-stage payload that may have been downloaded in the early stage of the attack - however; when I investigated shortly after, I didn't observe any secondary malware.

Update: the second-stage payload was the default Meterpreter by Metasploit. Updated analysis above. This does not affect or change the disinfection or removal steps.

Follow the prevention tips above to stay secure. Any questions or feedback? Feel free to leave a comment, or reach out to me on Twitter.


Wednesday, October 25, 2017

Comparing EternalPetya and BadRabbit

I've created a table comparing the EternalPetya (ExPetr, NotPetya, etc.) outbreak from June, and the BadRabbit ransomware outbreak from yesterday (2017-10-24).

I have decided to not include WannaCry (WanaCrypt0r), as they are not related, while EternalPetya and BadRabbit do seem very closely related, or even developed by (a part of) the same people.

Use freely, as long as you include a link to the original source, which is this blog post.

Comparison table (click to enlarge)

Download the table / comparison sheet

Additionally, you may find this image as a handy spreadsheet (which you can also download in several formats) on Google Docs here:

Note: this table or sheet will be updated continuously.

Purpose of BadRabbit?

Again, this makes you wonder about the actual purpose of ransomware, which you can read more about here: The purpose of ransomware

For BadRabbit in particular, it may be deployed as a cover-up or smokescreen, or for both disruption and extortion.


As for any prevention advise, have a look at the following page I've set up:
Ransomware prevention

Disinfection and decryption

Unfortunately, decryption is likely not possible without the cybercriminal's private key.

You may be able to restore the MBR, or your files, if you catch the ransomware in the act, and shutdown the machine at that point. Reboot in safe mode and copy over or back-up your files.

Then, Restore the MBR, and reinstall Windows.

You may also try to restore the MBR first, and consequently attempt to restore files using Shadow Volume Copies. For example, a tool such as Shadow Explorer can be of assistance, or read the tutorial here.

If that doesn't work either, you may try using a data recovery program such as PhotoRec or Recuva

Any questions, comments or feedback, please do let me know in the comments section below, or send me a message on Twitter. See also my About me page for other contact details.

Saturday, October 14, 2017

Notes on Sage 2.2 ransomware version

Sage, also known as SageCrypt, is an interesting ransomware variant - emerged somewhere in December last year, and is believed to be a variant of the CryLocker ransomware.

There's a good blog post on BleepingComputer on the first version of Sage, id est "Sage 2".

Yesterday, a personal friend of mine reached out, as his "computer started talking" and his files appeared to be encrypted. And indeed, it appears he suffered the latest variant of Sage: Sage 2.2

Sage 2.2 appears to have been out for a while, at least since February of this year:

Some figures of Sage 2.2 follow below:

Figure 1 - Sage 2.2 desktop background

Figure 2 - Sage 2.2 file recovery instructions

The message reads:

You probably noticed that you can not open your files and that some software stopped working correctly.
This is expected. Your files content is still there, but it was encrypted by "SAGE 2.2 Ransomware".
Your files are not lost, it is possible to revert them back to normal state by decrypting.
The only way you can do that is by getting "SAGE Decrypter" software and your personal decryption key.

Typical features of Sage 2.2, include, but are not limited to:

  • Refresh or update of payment pages is possible;
  • Ransom note (!HELP_SOS) and portal, including CAPTCHA;

It speaks! Just like Cerber did at some point, Sage 2.2 has a message for the victim using Microsoft SAPI:

Figure 3 - VBscript which will speak to the victim (click to enlarge)

Interestingly enough, even though the version number still indicates 2.2, there's at least one slight change:
  • Deletion or purge of backup catalog/history by using:
    wbadmin delete catalog -quiet

The portal or decryption pages look as follows, stepping through:

Figure 4 - Sage 2.2 user login portal

Figure 5 - Captcha

Figure 6 - Language selection

Figure 7 - Final portal

The victim can choose from a multitude of languages, and, at the final portal, there is a special price for the decryption, for a selected time (7 days): currently 0.17720 BTC, which is about $1000.

As usual, there's a Payment, Test decryption, Instructions, and even a Support tab:

Figure 8 - Payment tab
Figure 9 - Test Decryption tab

Figure 10 - Instructions tab

Figure 11 - Support requests tab

Sage 2.2 will append the .sage extension to encrypted files and currently, it does not appear files can be decrypted without the cybercriminal's help.

As always, try to restore from a backup if possible, and avoid paying the ransom.

Additionally, have a look at my ransomware prevention page, on how to protect yourself.


Wednesday, October 11, 2017

Rick and Morty episode? Nope, another CoinMiner

Last week I got an email from someone requesting help in regards to a possible malware infection: that person downloaded a torrent, and believed it was a legitimate episode of Rick and Morty, an animated series.

A file called Rick.and.Morty.S03E10.HDTV.x264-BATV.MKV.exe (116 MB in filesize) is of our interest and, what you'll notice first is of course the file extension - it's an executable Riiiiiiiiiiiick!

In fact, this file is a self-extracting and password-protected archive which contains two other files:

Figure 1 - two new files in the archive

One file is indeed a legitimate video file, which features the following:

Figure 2 - clip

This short clip has nothing to do with Rick and Morty, but seems to be a promo clip for a new series, called '1922'.

Inside the other file however, another executable, is another self-extracting and password-protected archive, sometimes referred to as 'SFX' with inside ... More archives.

In short, what you actually end up with is a cryptominer or coinminer. In Figure 3 below, you can spot both the passwords used for the archives, as well as the mining pool of interest:

Figure 3 - Passwords, and cryptominer pool (click to enlarge)

The line of interest is as follows, in where the IP points to a US server:

START "{1}" /B /WAIT /LOW "%ALLUSERSPROFILE%\{1}\{1}.exe" -o -u off.x -p off.x -k --nicehash -o -u off.y -p off.y -k -v 0 --donate-level 1 -B

Basically, this is yet another cryptominer or coinminer. This one is rather interesting, for several reasons. If you'd like to know more, feel free to have a play around with the files, they are included as IOCs at the end of this post.


If you've been hit by this, then...:

  • Navigate to C:\ProgramData or %ALLUSERSPROFILE%
  • Search for a folder with random names. If you don't see any, you may want to follow the instructions here. Delete said folder, if possible. If not possible:
  • Open Task Manager, and search for any process with a random name. End the process and repeat step 1 to 2.
  • Perform a scan with your installed antivirus product.
  • Perform a scan with an online antivirus, which is different from the one you have. Alternatively, perform a scan with Malwarebytes.
You may also leave a comment should any difficulties arise.


  • Install an antivirus (free or not).
  • Enable showing file extensions. This is hidden by default by Windows, and will enable you to see if that 'video' is indeed a video, or not. Guide here.
  • Do not download any torrents or at least try to avoid those that are either suspicious-looking, or too good to be true.


Coinminers have been on the rise for a while now, and illegitimately use a person's machine for mining, which may additionally lead to an increased (and undesired) CPU usage.

While coinminers for now are relatively less dangerous than what's usually out there, for example banking trojans, it should not be underestimated - and the sample analysed in this post proves the point, as it employed some rather unique, or at least varied, techniques.

It is likely safe to assume that not only the malicious use of coinminers will increase, but also that other malware may jump aboard - attempting to maximize profits (or vice versa, a coinminer with added persistence or other malware on board). The latter has already been observed, for example, in AdylKuzz.


Wednesday, September 20, 2017

Malicious ad/click networks: common or forgotten threat?


Malicious ad/click networks and ad fraud are not entirely a new phenomenon, but it is important to realize the kind of threat it may pose. Is it a common, or forgotten threat? Maybe both.

In this blog post, we'll take a look at how a seemingly innocuous click network and advertiser, is actually showing some rather malicious behavior.

The beginning

It all starts with the following redirect:

Figure 1 - .js download

A 'critical Firefox update' needs to be downloaded and run, with the resulting file having multiple layers of obfuscation. After deobfuscating 2 layers, we get the following:

Figure 2 - malicious script

The script will attempt to download an .flv file from ohchivsevmeste5[.]com, with additional parameters. While I was unable to reproduce what happened afterwards at time of writing, it would likely fetch another heavily obfuscated JavaScript, for clickjacking purposes (and this behaviour can also be deduced from Figure 1, as it persists in the browser).

Clickjacking is not an uncommon phenomenon unfortunately, and is described by Wikipedia as:

Clickjacking (User Interface redress attack, UI redress attack, UI redressing) is a malicious technique of tricking a Web user into clicking on something different from what the user perceives they are clicking on, thus potentially revealing confidential information or taking control of their computer while clicking on seemingly innocuous web pages.
Basically, what you see is not what you get. In this case, a Firefox update is anything but said update.

The persona

The domain mentioned in figure 2 is hosted on 192.129.215[.]157, which has a ton of other domains, with most of them appearing random. One of these domains is aiwohblackhatx[.]org, which is registered to a person with email address of abdelrahman.a.y.127@gmail[.]com.

This email address is linked to a Facebook page, mltaqaalwza2f2, which claims to be a jobseeker website:

Advertisements for newspapers, newspapers and websites The largest site jobs on Facebook for Jordanians only

Until recently, that page listed a contact email address as ADMIN@ULTIMATECLIXX[.]COM. This has now been changed, and unfortunately I was unable to take a screen capture at that time.

Ultimateclixx sports a flashing website, promising instant payment:

Figure 3 - Ultimateclixx website (at time of writing)

Passive DNS data reveals that the email address mentioned above, has links to other domains, and in particular to a person or persona called 'Mohammed Farajalla'. This persona has multiple email addresses set up, all pointing to click networks:

Figure 4 - Persona (click to enhance)

This initially lead me to believe that Abdelrahman and Mohammed are the same person, and is simply an alias. However, WhoIs data from another domain, aifomtomyam69[.]org, reveals a person named 'Abdelrahman Farajallah' as domain owner.


Figure 5 - Ultimateclix admin forum post (click to enhanceà

Brothers or not, it seems that Mohammed is the 'public face' of the company, and Abdelrahman works in the background, registering domains. A well-oiled business scheme, apparently.

In Figure 5 above, you can see a specific post from 'mhmadfarajalla', hereafter referred to as Mohammed, explaining how he joined Goldenclixx from 2013 onwards, and made quite some investments. This reply was motivated by a user questioning their legitimacy:

Figure 6 - concerns in regards to the Ultimateclixx admin (click to enhance)

This was posted in 2015 on the eMoneySpace forum, which is a website created to 'promote or talk about internet money related subjects'. Basically, how to earn money online using ads, which is completely legal.

Link to topic can be found here:

I've also set up a mirror here:

It appears Abdelrahman and Mohammed have been involved in this scheme for a prolonged period of time. While they may have initially started their project or business as a legitimate way to make money, this has definitely shifted. They are likely located in Palestine. (see also his/their Twitter account, and make your own deductions.)

The infrastructure

Earlier, I mentioned that domains involved seemed random. Have a look at these domains:


Notice anything particular? If not, what about the following domains? (includes our initial example)


To clarify, the 2 first characters are the same for a whole set of domains, while the rest does appear to be (at least semi-)random. Just as a visual aid, here are a few other domains:



You may have noticed vahfebankofamerica[.]net in there, it is relatively newly registered (2017-09-12), by a 'Megan Quinn', with email address of qum65@binkmail[.]com. I doubt an actual Ms. Quinn would use this email address. It may try to convince users of its legitimacy, alluding it is part of Bank of America's website. However, nothing could be further from the truth.

Interestingly enough, the domain has hosted a JavaScript at least once, with a familiar pattern:

No doubt this website would also prompt you to download a 'critical security update'. Do I hear redirects mixed with ad or click-fraud and clickjacking? Who doesn't love the smell of that in the morning?

You would not have guessed, but a lot of email addresses seem randomly generated, as well as their personas. Another example includes:

Figure 7 - ohchivsevmeste5[.]com WhoIs info

Everything in the WhoIs info is fake. Not to say an Allan Yates doesn't exist, but he has nothing to do with any of this - rather he was just unlucky. This may have been the result of a 'fake name generator'.

We now have several IP's hosting a bunch of semi-random domains, set up for redirects, ads and likely clickjacking. The initial research started with 192.129.215[.]157, and expanded to/had links to 192.129.215[.]155.

Of course, I decided to take a look at 192.129.215[.]156. Surprise! It turns out it's just as bad. Maybe we should just block the whole subnet?

Some more takeaways from the infrastructure - most of the domains are or have:

  • WhoIs Guard Privacy Protection/Privacy Protect:DomainsByProxy;
  • Behind CloudFlare;
  • A valid SSL cert, issued by Comodo.

What else is there?

Earlier, Mohammed boasted in his forum post about, one of his new websites, and absolutely 'no ponzi scheme strategy'.

Some of the related websites provided by Mohammed are:

Figure 8 - adzbazar[.]com

Figure 9 - clikerz[.]net

I think you can start seeing a pattern here.

Circling back, with our email address abdelrahman.a.y.127@gmail[.]com, I noticed another registered domain, adz2you[.]com. You could zay zomeone likez the letter Z. Either way, using PassiveTotal's host pair functionality, we can find a hostpair with gptplanet. Gptplanet claims to:

Earn money by completing simple tasks online. Everyone can join, it’s absolutely FREE!
As far as I could see, this claim is indeed legit. As far as Mohammed and all his domains go: it didn't take me too long to dig up a forum post with an on-the-point title:

Link to topic can be found here:

I've also set up a mirror here:

The topic on gptplanet also references to eMoneySpace, a forum mentioned earlier, and specifically, several topics are set up about 'referral' websites our dear friend Mohammed has set up.

One user made an excellent remark:

It comes to my realize for a whole year now, is that some people are implementing some malicious scripts onto their advertised ad for a user to click on it.

Nail, head, hitting it. It seems that Mohammed isn't done yet however with both scamming people, and infecting users:

Figure 10 - Offers4all invitation

There is also mention of another person, 'Agony'. This nickname may refer to Abdelrahman.


Prevention in this case is rather short, so here goes:

  • Install an antivirus;
  • Keep your browser up-to-date;
  • Install NoScript if you have Firefox;
  • Install a 'well-rounded' ad-blocker, for example uBlock Origin (works with most browsers).

And, where possible, browse the internet with caution.

Note that the campaign on 192.129.215[.]157 remains highly active, and as such, it is recommended to block or blacklist it, as well as the other domains and IPs, provided at the end of this blog post.


When you get a prompt for download or running a 'Firefox patch' similar to above, or any other pop-ups for that matter - where you not instantiated a download yourself - cancel the download or, if not possible, kill your browser's process. This can be done via Task Manager for example.

While I haven't seen any evidence of other malicious behaviour besides ad, click-fraud and clickjacking, it is recommended to:

  • Uninstall and reinstall your current browser, along with its extensions;
  • Perform a full scan with your installed antivirus product;
  • Perform a full scan with another, online, antivirus product, or with Malwarebytes;
  • Change your passwords.

Additionally, you may check in your firewall or proxy logs, if there was any connection at some point with any of the domains or IPs provided in the Indicators OCompromise section below.


Ad fraud, clickjacking, ad networks, .... There are tons of similar networks out there. While ad networks are usually not malicious, other possibilities exist , such as:

  • An ad network is compromised;
  • An ad is compromised;
  • The ad network is malicious in itself.

Probably, at some point, there should be better security controls for ad networks, in order to prevent an attack or campaign such as the one described in this blog post. Proper security hygiene is necessary for the ad networks, but just as well for any website that serves up ads.

Clickjacking and click-fraud is a common and a very real threat. Are you watching your logs, and acting on them?


Thursday, August 24, 2017

Crystal Finance Millennium used to spread malware

Earlier today, Costin from Kaspersky tweeded the following intriguing tweet:

After some hunting, it was revealed the Crystal Finance Millennium website was indeed hacked, and serving three different flavors of malware. In this short blog post, we'll take a look at the malware variants that were distributed, and provide minimal background.


Crystal Finance Millennium' website is currently taken offline by the hosting provider, but archives of the website exist online.

Figure 1 - "At this moment the site is blocked by the hosting administrator"

From the archived webpage, it becomes apparent they provide accounting software, peronalisation of medical records, blood service and "full automation of the doctor's office" - contrary to what their company name suggests, it appears they are (mostly) focused on medical software.

Figure 2 - archived webpage of CFM's services

Moving on to the malware present on their website:

Smoke Loader

Smoke Loader, also known as Dofoil, Sharik or just 'Smoke', is a botnet with the main purpose of downloading other malware - a downloader. 

Smoke Loader was originally downloaded from:

Additionally, it was also mirrored at:

Smoke Loader drops itself in a random directory inside the user's %appdata% folder, for example:

Additionally, it performs an HTTP POST request to the following domains:

SmokeLoader has a debug path which is likely fake, or automatically generated:

We won't go any further into Smoke Loader here, but there's an excellent blog post by @hasherazade over at Malwarebytes here:
Smoke Loader – downloader with a smokescreen still alive


Chthonic is a banking trojan and derivative of Zeus, well-known banking malware. Zeus, also known as Zbot, was leaked several years ago and has since then spawned multiple new, and often improved, banking trojans.

Chthonic uses a custom encryptor and, as a result, its payload hash will differ every time.

It was observed as a dropper from the following websites:


Additionally, it drops its payload into the user's %appdata% folder; for example:

While Smoke Loader employs totally random filenames, Chthonic tries to hide by looking like a legitimate program.

It performs an HTTP POST request to the following domain:

Interestingly enough, Chthonic was spotted in June targeting a government institution in Ukraine:
Chthonic Trojan is back in nation-state cyberattack against Ukraine

Whoever's behind this Chthonic campaign however, has a sense of humour by sporting the following debug path: C:\postmaster\merge\Peasants\Billy.pdb

Chthonicwill also create a simple batch file which goes through a loop and will delete the dropper and the batch file once it has installed the payload.


PSCrypt, which is based on GlobeImposter, another ransomware variant, has been hitting Ukraine in the past:

Interestingly enough, the same PSCrypt campaign was spotted earlier this month by @malwarehunterteam:

This tweet suggests the attacks started as early as the 14th of August.

PSCrypt was originally downloaded from:

PSCrypt will encrypt files and append an extension of .pscrypt - in order to restore your files, which asks for 3500 Hryvnia (~ EUR 115):

Figure 3 - PSCrypt ransom message
PSCrypt provides a fully detailed ransom message on how to send bitcoins to the cybercriminal, as well as a personal ID ("Ваш личный идентификатор").

Additionally, PSCrypt will remove RDP related files and registry keys, likely to prevent an administrator to clean an infected machine remotely. It will also clear all event logs using wevtutil:

Figure 4 - Batch file which goes through commands in sequential order

Whoever's behind this PSCrypt campaign also shows sign of humour, indicating an address in the US, pointing to a company called "Unlock files LLC". Such company does not exist:

Figure 5 - Unlock files LLC address

Figure 6 - Companies at the same address

Unfortunately, the Bitcoin address shows a history of already paid ransoms, dating back to the 15th of August: 1Gb4Pk85VKYngfDPy3X2tjYfzvU62oL

At time of writing, a total of 0.0924071 has been received, which is around EUR 328.

Since the first payment was on the 15th of August, this supports the theory of CFM's website being compromised at least before or on the 15th, quite possibly the 14th.

The general recommendation is to NOT pay, but rather restore files from a backup.


While Crystal Finance Millenium's website was hacked, it's possible its software was not affected. In the mean time, I'd advise to not upgrade or update any software belonging to the company, but rather wait for an official statement from their side.

The hacking of a company or personal website can always happen, and as such, it is important to act fast once it's happened - the (hosting) company did the right thing to take the website offline while things are being fixed in the background.

The bigger question here is if it may be a targeted attack - recently, Ukraine has been targeted heavily by not only EternalPetya (also known as NotPetya), but also by Xdata and PSCrypt. Additionally, seemingly targeted attacks had Chthonic as payload, and, as reported in this blog post, another software company in Ukraine has been compromised.

As usual, best is to wait until further data is available before making any judgments.

Prevention advise for ransomware can be found on my dedicated page about ranomware prevention:

And, as always, indicators of compromise (IOCs) can be found below, as well as additional resources.



New Cyberattack wave is launched using officialweb site of the accounting software developer«Crystal Finance Millennium» (PDF)
“Crystal Attack” analysis – behavior analysis of the “load.exe” sample (PDF)

Wednesday, July 19, 2017

The purpose of ransomware

Ransomware, a phenomenon now very well known, serves one ultimate and obvious purpose:

  • Monetary gain for the cybercriminal(s).

However, multiple scenario's are, in fact, possible. Consider any and all of the following:

  • Deployed as ransomware, extortion;
  • Deployed as smokescreen;
  • Deployed to cause frustration;
  • Deployed out of frustration;
  • Deployed as a cover-up;
  • Deployed as a penetration test or user awareness training;
  • Deployed as a means of disruption and/or destruction.

Let's go over all of these briefly:

Deployed as ransomware, extortion

This has been the traditional approach - ransomware is installed on the victim's machine, and its only purpose is to create income for the cybercriminal(s).

In fact, ransomware is simple extortion, but via digital means.

I could give 100s, if not 1000s of links as example, but this search query should suffice and show the current boom or trend in the cybercriminal landscape:

Deployed as smokescreen

A very interesting occurrence indeed: ransomware is installed to hide the real purpose of whatever the cybercriminal or attacker is doing. This may be data exfiltration, lateral movement, or anything else, in theory, everything is a possible scenario... except for the ransomware itself.

This may happen more than you think and begs the question - what is the real purpose here?

Ransomware is obvious: files are encrypted, warning or extortion messages are scattered, and users as well as companies are unable to proceed working for days, depending on backup and recovery strategy.

Once you're hit by ransomware, more than 1 alarm bell should start ringing - you are royally compromised and, as such, should take appropriate measures immediately. There may be more than meets the eye.

There's an article on Carnal0wnage, describing one of these events:

Deployed to cause frustration

Another possible angle that goes hand in hand with the classic extortion scheme - deploying ransomware with intent of frustrating the victim. Basically, cyber bullying. While there may be a request for a monetary amount, it is not the purpose.

A notorious example of this is the Jigsaw ransomware:

Another example may be to send ransomware 'as a joke' to your friends, and giving them a bad time. Don't.

In a related example; a victim of a tech support scam tricked the scammer into installing ransomware:

Deployed out of frustration

Sometimes, an attacker may gain initial access to a server or other machine, but consequent attempts to, for example, exfiltrate data or attack other machine, is unsuccessful. This may be due to a number of things, but often due to the access being discovered, and quickly patched. On the other hand, it may have not been discovered yet, but the attacker is sitting with the same problem: the purpose is not fulfilled.

Then, out of frustration, or to gain at least something out of the victim, the machine gets trashed with ransomware.

Another possibility is a disgruntled employee, leaving ransomware as a 'present' before leaving the company.

Darryl from Kahu Security has written an excellent article on the former occurrence:

Deployed as a cover-up

This may sound ambiguous at first, but imagine a scenario where a company may face sanctions, is already compromised, or has a running investigation.

The company or organisation deploying ransomware itself, is a viable way of destroying data forever, and any evidence may be lost. 

Another possibility is, in order to cover up a much larger compromise, ransomware is installed, and everything is formatted to hide what actually happened.

Again, there is also the possibility of a disgruntled employee, or even an intruder: which brings us back to 'deployed as a smokescreen'.

There are some statistics referring to this as well, in a report by SentinelOne:

Deployed as a penetration test or user awareness training

Ransomware is very effective in the sense that most people know what its purpose is, and the dangers it may cause. As such, it is an excellent tool that can be used for demonstration purposes, such as a user awareness training. Another possibility is an external pentest, with same purpose.

An example is given by Malwarehunterteam, where KBC Group employed a phishing test, and consequently 'ransomware', meant as user awareness training:

This is a very good idea for any organisation or business in general. Are your users aware of the dangers that lie in, and beyond ransomware?

Deployed as a means of disruption and/or destruction

Last but not least -  while ransomware can have several purposes, it can also serve a particularly nasty goal: destroy a company or organisation, or at least take them offline for several days, or even weeks.

Again, there are some possibilities, but this may be a rivalry company in a similar business, again a disgruntled employee, or to disrupt large organisations on a worldwide scale.

A recent and notorious example of such an attack is the latest Petya variant, also referred to as EternalPetya, or NotPetya. A blog post from Kaspersky suggests the main purpose is a wiper:

In a way, this also falls back to the frustration, and cover-up scenario's.

Closing thoughts

As we've seen, ransomware can serve a plethora of purposes; whether it is deployed by a nation-state actor, the more common cybercriminal, or your neighbor disgruntled at your tree hanging over their wall, one thing is for sure: you are, and have been compromised!

In more recent years, targeted ransomware has become a common phenomenon, this means ransomware either tailored to your environment, or manually installed - the latter often via hacked RDP or VNC services.

The most famous example is no doubt Samas, also known as SamSam:

Other examples include: CrySiS and derivatives, RSAutil and PetrWrap. 

While targeted ransomware attacks are occurring as early as 2013, in most recent years, they have become more fearful, due to the ransomware also encrypting files.

Conclusion: ransomware is and will always be ransomware - but it may have a twist and an additional purpose.

For further reading, I gladly introduce a shameless plug by referring you to 2 of my blog posts:
Ransomware prevention

This blog post also exists as a dedicated page here: the purpose of ransomware.

If you can think of any other targeted ransomware, or purposes for ransomware, do not hesitate to leave some feedback in the comment section, or contact me on Twitter.

Wednesday, June 21, 2017

Display Color Calibration tool DCCW and UAC bypasses

In today's post we'll look at yet another way to bypass UAC using the Display Color Calibration tool, hereafter referred to as "DCCW".

DCCW has already been exploited in the past to bypass UAC, more specifically, by leveraging DLL sideloading:

This research started by helping out a friend with display issues some months ago, and stumbling upon the DCCW tool, or more specifically, the following blog post:
Using the Display Color Calibration Tool (DCCW.exe) in Windows 7 to Get the Most From your Display

Being inspired by Matt Nelson, I decided to have a closer look as to how and why this may be a UAC bypass.

What follows below is purely a Proof of Concept, as you would already need to have compromised the machine (or bypassed UAC, or let the user allow) in order to execute this.

Regardless, it can be used for persistence, and I'd still like for you to following along on my journey inside the wondrous world of UAC bypasses  :-)

This has been tested on: Windows 10 and Windows 8.1 x64 and x86.


  • User has to be member of the local administrator group.
  • UAC is ... already disabled, or at a low setting, or the user confirmed the UAC prompt.

DCCW is a Microsoft signed binary and will auto-elevate itself due to its manifest.

Figure 1 - verified, signed Microsoft binary (using Sigcheck)

Figure 2 - autoElevate is set to 'true'

Running through the DCCW wizard, we can happily click next, until the end of the wizard the following is displayed:

Figure 3 - end of DCCW wizard

Note the automatically enabled or ticked checkbox:
"Start ClearType Tuner when I click Finish to ensure that text appears correctly (Recommended)"

Launching procmon and executing DCCW; the following can be observed:

Figure 4 - DCCW loading CTTune

As you notice, DCCW attempts to open, and read, the subkey in:
HKLM\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options

Image File Execution Options (IFEO) has several uses, and can for example be used to prevent a program from starting, For example, in the past, malware has abused IFEO to hijack processes of antivirus programs, so they would not be able to start.

Back on topic, creating an IFEO using CTTune, we can start anything at the highest integrity (and circumvent the UAC prompt) ... Including PowerShell :-)

Figure 5 - Launch of DCCW, note the High integrity


Figure 6 - PowerShell started with High integrity (normal level of integrity is Medium)

To try this yourself, create a new key in:
HKLM\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options named CTTune.exe, consequently create a new value named 'Debugger' and in the Data section, place whatever you want. Example:

Figure 7 - CTTune IFEO


Figure 8 - PowerShell running as administrator, with highest integrity

This attack is more theoretical, rather than practical, due to the need for initial admin permissions, the DCCW wizard appearing, and the user having the need to click through. The main point here is that no UAC windows will appear asking the user for permission, once the IFEO is set, and DCCW is started. Some other points to consider:

  • Users love to click on things, especially 'Next' in wizards :-)
  • You can try social engineering to entice the user in allowing UAC, & clicking through
  • You can try extending the PowerShell script below, by simulating mouse clicks or button presses in PowerShell - effectively impersonating the user.

You may find the PowerShell script here on Github:

If I made any mistake(s) in the script, please do let me know!

Finding UAC bypasses

If you like to try new things, then trying to find a UAC bypass can definitely prove to be a challenge and fun! While my story here was both successful and not - I found a UAC bypass, but with limitations, it's still good to go out of your way and do something you're less familiar with.

For finding UAC bypasses, or other strange, weird or old Windows artifacts and binaries, I can definitely recommend the following tools:

Process Explorer

Process Monitor



IDA Pro Free:

A Windows system, and a C:\Windows\System32 and/or C:\Windows\SysWOW64 folder.

Additionally, have a look at the Resources section at the end of this post.


Obviously, you would like to prevent these specific bypasses from ever occurring. Please find below some recommendations I've compiled:

Additionally, have a look at the Resources section at the end of this post.


UAC bypasses are an interesting domain: while Microsoft seems to take a 'lighter' approach in regards to these specific bypasses, it doesn't mean they aren't being looked at. For example, latest releases of Windows 10 fix several UAC bypasses.

My hope is that, by accumulating the info in this blog post and following along my journey, you may find other UAC bypasses, or other cool stuff lying around :-)

Keep in mind that UAC bypasses are definitely out there in the wild - not only by pentesters, but also by attackers, whether cybercrime or APTs.

As always, feedback is appreciated.


Defeating Windows User Account Control (UACME)
Dridex Returns With Windows UAC Bypass Method
Enigma0x3's blog (tons of good stuff in there)
User Account Control: Inside Windows 7 User Account Control
User Account Control Step-by-Step Guide