Ransomware decrypters

Filing for future reference for reference in case of a ransomware infection. This list gathers together a list of tools and references that may allow you to get access back to encrypted files.

Remember the best way to not get infected is to install a cryptolocker prevention tool (I use the Cryptoprevent), watch the sites you go to, educate yourself on what a phishing attack looks like, don’t run as administrator, use opendns (or google safe browsing) and ensure you have a good backup that is not accessible from your normal machine with your normal credentials.

If you know of any others then please let me know.

Edit – https://www.nomoreransom.org/ is also a good resource and probably should be your starting point. It even allows you to upload an encrypted file (or the ransom note) and will then check what version of crypto you have and let you know if there is a decrypter available for you.

A laymans guide to malicious files and why you shouldn’t always trust the software.

It was an interesting week at work with several malware infections making it through the various av protections that we have in place which proves that end user education should be your primary line of defense in the fight against virus’. It is amazing how often people will click on random emails that have been sent to them with random filenames just because the email arrived in their inbox (or in another mailbox that they happen to have access to), even if it was not addressed to them.

I was lucky enough to get one of these emails through to my corporate mailbox on Tuesday this week, evading detection by McAfee email protection and Forefront on the desktop. (Using another av solution would not have prevented this as you will see later)

Fake looking email
Would you trust this email?

This was obviously some scam with the description of the user not even matching the email address of the user. Being curious, I naturally saved the file to my hard drive and then uploaded it to virustotal. On Tuesday, only 1 of 58 av engines recognised this as a virus – kudos goes to Quihoo-360 for being the sole detector. I must admit that I’ve never even heard of this software and I was very surprised to see that only 1 av vendor recognised the file.

Tuesday morning's virustotal result - only one av picking it up from Quihoo-360

I submitted the file to McAfee for scanning by zipping the file up with 7-zip and password protecting it with the phrase infected and sending it to their response team at virus_research@mcafee.com. Incidentally, McAfee’s instructions for doing this are very outdated as Windows10 no longer has the option to password protect a zip file. McAfee immediately came back saying that their analysis was inconclusive and the file had been submitted for further research.  This was an improvement on the previous sample I had submitted on Friday for a cryptolocker variant that came back as no virus found!

Wednesday morning I uploaded the file to virustotal again to see what the state of detection was.

This time the detection rate was slightly better – 9 products including Sophos that I use at home, but neither of the products in use at the office.

Wednesday morning detection rate

Thursday morning, two days after receiving the virus I received a response back from McAfee that confirmed the file was malicious. They included an extra.dat that would detect the file.

By this time, virustotal was showing 25 out of 53 products detecting the virus so it is getting better. Microsoft’s product was listed as detecting the file, yet Forefront was still passing it through as clean. Although virustotal has the definition date of 7/28, my computer was showing “defs of 7/26, update on 7/27”. Not sure why there is this discrepancy of the definition dates.

Yesterday, my laptop at home still had old definitions as it was not connected to the corporate lan and was still showing the file as clean which is pretty scary.

This morning I downloaded the file to my personal laptop, saving the file with a .txt extension so I would not accidentally open it – something that is easier to do on a touch screen tablet. Interestingly Sophos did not detect anything wrong with the file. Launching the file in notepad, it starts with the letters PK which implies the file is actually a zip file and there are several strings referring to HP printers and Adobe Photoshop.Snipped notepad view of infected file

At this point I’m not going to risk my machine further by opening it with 7zip to see what happens.

However when I copied the file to .zip or to .rtf Sophos did spring into action and quarantine the file. This is really handy as it protects the file from being saved to the machine in an executable form, but also allows you to save the file to the hard drive for further analysis in your debugger of choice.  Other applications will quarantine the file no matter what the extension is, making it harder to retrieve. On the other hand, you now have an infected file on the machine that av is not discovering.

This Sunday morning, I uploaded the file to virustotal again. This time we’re slightly better at 29/54 detections. However, Comodo, Malwarebytes, Panda, SuperAntiSpyware,Symantec, TrendMicro and Vipre (among others) do not detect the file as malicious.

Malware bytes is an interesting discovery as it’s not usually regarded as an av product as it typically protects you from software being installed into suspicious locations such as autorun, startup, browser toolbars etc as opposed to traditional av that scans every file being written or read to the hard drive. However in this case and my recent cryptolocker, MalwareBytes failed to find anything malicious although HitManPro did find the Cryptolocker exe file on the machine (but MalwareBytes and McAfee did not).

The best av is the human kind that recognises a file is suspicious or unexpected and does not open it – although even this kind of av can fail (and some are more prone than others!)

Incidentally, one of my favourite solutions for the Cryptolocker variant, in theory at least, is pretty drastic and requires the permissions of file shares to be changed so that files can be created but they can’t be edited. Users (and software) would be able to write new files to the file share, but any edits to the file would not be allowed unless the changes are written to a new file. This forces users to do Save-As all the time, may break Office documents that insist on modifying the original file, but would stop Cryptolocker from overwriting files on the drive. Obviously this takes up a lot more disk space and would not be suitable for shares holding Autocad documents.

*Please note that this post is not meant to denigrate any one particular av product in particular as I understand that definitions take time to produce but av software that does not detect infections 5 days later should probably be evaluated to see if it is safe for continued use.  I do reserve the right to moderate comments on this post if they are not helpful and just say “Product XYZ is useless”

Preventing Trend Micro from scanning server after the umpteenth time of installation.

When you have a problem with Trend and have to keep reinstalling it on the server, it gets extremely frustrating waiting for the agent to do a prescan and then fail to complete the install due to “unable to install the client/server security agent.Contact Trend Micro support. Error copying FlowControl.dll”

The problem of flowcontrol.dll can be fixed by deleting the trend micro\Client Security Agent folder after you have uninstalled the software. If you get a problem deleting perficrcperfmonmgr.dll then unregister it with regsvr32 /u perficrcperfmonmgr.dll  Wait a few seconds and then rename the Client Security Agent folder to .old.  Repeat the installation and the software should install with no problems.  (Note that you may have to reboot if the Security Agent service fails to stop)

To prevent the server from rescanning for virus’s (which after all it has been doing in the past and will take a long time on a server), edit the autopcc.ini that can be found in the \\server\ofcscan\autopcc.cfg folder.  Change NoPreScan to 1 instead of 0 and then run the autopcc.exe install program.

For what it’s worth, we are looking at using Trend due to some of the features such as the Remote Manager capabilities and the fact that they do seem to listen to their users and resellers.  I had a good training session with one of their Technical managers a week ago which was really great. unfortunately the install that sparked this blog post has caused me no end of problems and Symantec would be a much more efficient install in this case.

Symantec definitions slowly getting fixed.

Symantec have now released a patch that fixes the issue of definitions being dated 12/31/2009. However, the patch so far is only available for those running 11.03 or 11.05. For more details read the official statement on the Symantec forums or the Symantec Knowledgebase article . Most of our Endpoint Protection Servers were running 11.0.4 (as live update does not upgrade the server console component) so we have to upgrade to 11.0.5 first. This can be seen as a good thing as 11.0.4 has the nasty feature of filling up the hard drive of the server as Symantec downloads and keeps 3 copies of the av definitions every few minutes as it tries to download definitions dated in 2010 (and fails). So far, most of the Endpoint Protection Manager upgrades have been fairly simple with straightforward instructions – a 25 minute process after the files have been downloaded (including backing up the database) but we had one site that didn’t work and we had to reinstall every single Symantec Endpoint Protection client and server by hand. Not a lot of fun.

Symantec patch now fixes the definitions dated 91231

Yes I deliberately posted the date this way as that is how the shortsighted programmers as Symantec did it. Needless to say, when the year rolled around to 00101 this is a lot less that 91231 so the definitions were treated as old.  It scares me to see that this bug managed to get into the product – did they not learn anything from the Y2K issues?

To make matters worse we found some servers were continually downloading definitions onto the server and in one case filled up 73gb of disk space. The fix for this is to ensure that the endpoint protection manager software is running 11.0.5 – this is a new download and upgrade installation although for one of our clients it meant uninstalling and reinstalling every single pc at that location – not an upgrade at all.

To top it all, Symantec also decided this week to announce the end of life for the v10 of their products – the only version that was actually working with correct definition dates. Although end of life is in 2012, support should really have coordinated with sales to ensure that the notice didn’t go out *this* week.

I think I still have a few servers that haven’t updated, so I will be checking those out next week. If we continue to use Symantec (which I really do not want to do), I’m hoping to look at an MSP installation of the product – one server managing all the clients so I only have one place to check for client status (and only one server to install, patch and configure)

Antivirus plus removal during Thanksgiving.

It’s been a busy Thanksgiving weekend – I spent a lot of time on Thanksgiving working on a relative’s EEE netbook which had “problems”.  That was about as technical as you get for the error report but on seeing the “windows security center” program that popped up on initial login I knew I was in for some fun.

The fake av software Antivirus plus was removed with the help of the BleepingComputer Antivirus plus removal guide but there were a few oddities in the process.

One of my favourite tools is a removable usb thumbdrive with a write protect switch so I can update the thumbdrive, set it to readonly and then use it on an infected pc without worrying about infecting my thumbdrive – incidentally I tried to find another one of these on Black Friday at Microcenter but was unable to do so. Anyway, prior to going to Thanksgiving dinner I updated my Ketarin Whatsmypass setup so I would have all of the av tools I needed (or so I thought)

Following the removal process I needed to download the rkill.com file which killed the virus process’ and malwarebytes was installed. I needed to download the random filename for malwarebytes and oddly enough the documentation doesn’t mention that if you download this on the infected pc then you are likely to kick off the antivirus plus program due to it’s hooks into ie that have not been cleaned up yet. I know this is common sense for the seasoned av cleaner, but newbies following the steps blindly may get reinfected during the process.

It would be really nice if malwarebytes would include the latest definitions as part of the install when you download the original file but I guess they don’t want to rebuild their setup program every night. After a bit of research today I’ve found that you can get the latest definition updates online so I’ll be updating the ketarin for that too.

After the virus was removed it was time to update the pc for windows updates. The first round was 72 windows patches. I couldn’t use my autopatcher/offline patcher cd as the eee pc did not come with an external drive so I had to wait about an hour to install them. After a reboot, there were another 34 to download – by this time my relative had to leave to drive home so I gave her instructions on what to do – the first two were to buy a router so her pc is not directly attached to the internet and to boot the machine up and leave it on overnight at least once a month for the windows updates to install.

Hopefully she’ll get used to firefox as her default browser 😉

The funny thing is I was asked how much they owed me for the work… I spent 5 hours (on and off) on the machine all told – they purchased it for $150. I know it would be hard to find it for that price again, but they could have purchased 2 of them and had change left if I had charged them the going rate.

As to the pc itself, this was my first exposure to the eee pc – I was pretty impressed. It wasn’t too slow (although the scan took forever) so would make a good portable pc for web browsing use.  At this point I didn’t have my Chromium OS thumb drive or I’d have given that a go to see how Chromium performed on the machine.

Symantec Enterprise Protection (SEP) firewall requirements for client checkin.

So I’ve spent ages troubleshooting and debugging Symantec’s Endpoint Protection (SEP) version 11, MR4 – the first version that actually has a hope of working  on a 64bit platform.  After spending far too long configuring the various policies and tweaking various settings I was finally able to get the software installed via group policy on a testlab machine but the client would not checkin with the management server. The virus definitions were 4 months old BUT the client console was saying everything was ok. Lots of troubleshooting later and I stumbled across the definitions for the Management server – a setting that I had originally wanted to change anyway.  In there I saw that the management server was listening on port 8014 and a quick telnet check from the client showed I was unable to connect.  Disabling windows firewall (temporarily – this is on a testlab so the infection risk is minimal) allowed the client to check in with the server, change some settings in the console and update the virus definition dates. Finally I re-enabled the firewall, added an exception for TCP port 8014 and it all looks good, but I’ll wait to see what happens overnight for definition updates on the client.  For future reference the list of communications ports for version 11 can be found at Symantecs website here or posted below in the extended entry. Continue reading “Symantec Enterprise Protection (SEP) firewall requirements for client checkin.”

Latest malware removals.

I had two pc’s given to me last weekend to fix various speed issues. Thankfully I had downloaded the AntiMalwareToolkit from Lunarsoft recently so I did a quick update which meant I had a lot of antivirus and antispyware tools with up to date definitions ready on a cd.
The first machine was pretty straightforward and just needed ad-aware removing and reinstalling to fix ad-aware crashing on bootup. At the same time I scanned for virus and was pleasantly surprised to see none on the machine. The combination of Norton 360, adaware and malwarebytes had done a good job. Norton was crippling the speed of the machine though and I had to disable Norton whilst I ran other diagnostics on the machine as it was just painfully slow whilst running.

The other machine was a whole other story. Norton AV2004 does not do a good job of keeping machines protected when the definitions were last updated in 2005, although I think you’d all agree that no other product would either! Running MalwareBytes detected 400 antivirus files ranging from vundo,trojans, spyware2009 and other infestations. My initial scan was run after booting the machine into safe mode – normal mode was unusable, taking 6 minutes to launch regedit after eventually managing to hit start/run and type in regedit.
The initial scan took over 8 hours to run. Unfortunately I had not cleaned out the temporary internet files on the machine – all 18gb of them! After the first scan completed I selected all the temporary internet files and deleted them. It took about 20 minutes for windows to finish the “preparing to delete” stage. I’m not sure what exactly it is doing, but it is incredibly annoying to hit delete, walk away from the computer and come back 20 minutes later to see it then popup and say “are you sure you want to delete these files?”. I could have deleted the files from a dos prompt but it was taking forever to do anything, so opening a dos prompt and then navigating would have been very painful.
So after 3 hours of deleting files, a reboot I did another scan. This time it took 2 hours. So the moral of the story is to delete temporary internet files first. Interestingly I later ran AdAware and that actually asked me if I wanted to delete these files before it did the scan.
The machine was now fairly responsive…..in safe mode, but still took forever to do anything in normal mode. Scans were coming up clean so the configuration was obviously still screwed up somewhere. I tried to uninstall symantec using their uninstall package but that just hung using no cpu usage so it was a hard reboot and I tried the Norton Removal Tool. The first time it would unpack the self extracting exe but do nothing after that.
At this point I came across a thread in software tips and tricks with the same symptoms of the machine running slowly and the start button being unavailable. This thread was started in 2004 so I was a bit pessimistic about the solution of running a reg cleaner (as most of them are not really worth bothering with). However several people had responded saying that the solution worked, with a couple of posts from Jan 2009 so I figured it was worth a try. I had never heard of the registry cleaner, but I had heard of Jv16 Powertools, so I downloaded RegSupreme and let it do it’s registry cleanup. I looked briefly through the results and could see nothing really unusual so I rebooted and was really surprised that the machine started to respond normally. I was then able to run the Norton Removal Tool and remove Norton from the machine completely.
I haven’t completely finished with the machine yet, but I’m nearly there. You may be wondering why I took so long on this machine. To be truthful, if it was mine I’d have wiped it straight away, but as the issues got harder to fix, my stubbornness and curiosity got the better and I needed to know how to fix the problem and retain the data on the machine. After all, formatting is the easy way out and one day I’ll have a machine that I MUST repair in order to get data and this experience will have given me some helpful experience and preparation for that day.

64bit Symantec Antivirus does not update from Management Server

Discovered that 64bit clients of Symantec Antivirus have to be set to get their updates from Symantec servers using LiveUpdate, not from the Management server (as you would normally set the configuration to be). This may involve creating a new management group in Symantec’s Administration console and setting the update to not use the parent server as per the screenshot below.
Set this to ensure Symantec Antivirus 64 bit clients update  (by absoblogginlutely)

Symantec have a time machine!

I logged a ticket with Symantec today as I needed to download Maintenance Release 7 for their corporate edition 10.1 yet their fileconnect website only gave me version 11 (which is so unstable we refuse to install it). 2 hours later I got an email from their support site that started “We have been trying to reach you in the last few days to assist you with the issue regarding Symantec Antivirus but unfortunately we have not been able to do so.”
I guess they’ve invented a time machine in order to try and beat their really long wait times on hold for support…..either that or I forgot that I logged a ticket several days ago and they’ve finally got round to dealing with it!
Anyway, they’ve given me a new serial number to log into the website with so I can download the older version. I’m not sure if it’s an inplace upgrade (I hope so) rather than a removal and reinstall again – if its the removal and reinstall that means *another* 3 or 4 hours to remove, reboot, install and then fix the issues of the client software breaking other software again.
I guess I *really* need to get some time to investigate nod32 network deployments – anyone had any experience with this?