Wednesday, May 13, 2015

Backup, backup, backup!

Did you miss that?  I said BACKUP!

 A recent issue highlighted this once again.  A computer had been infected by AlphaCrypt.

This is a recent incarnation of one of those nasties known as ransomware which encrypts ALL of your files and then offers to sell you the information required to decrypt them.

Once they are encrypted you have a number of options
  • Pay the ransom (several hundred pounds) and HOPE that they are honourable enough to let you have the key
  • Restore all your files from backup (you do have one, don't you?)
  • Accept that you've lost  all your data; all those photgraphs; all those documents; all those business accounts!

How it works

Put very simply, there is an encryption method known as asymmetric encryption where two keys are used; a public key is used to encrypt a message (or whatever) but only the private key can decrypt it. 

Say, for example, I want you to send me some secure information, I can generate such a key pair and send you (and everyone else) the public key so you can encrypt the message but only I can decrypt the message since only I have the private key.  There's quite a good description on wikipedia.

What this nasty does is to load the public key onto your computer and then go searching for files.  This includes your hard drive PLUS any drives that are plugged in to any USB ports - so don't leave your backup drive connected all the time!  Each file then gets encrypted using the public key and then they offer to sell you the private key.

So how can I help

The best thing I can do is encourage you most strongly to BACKUP!  If you need advice or a system setting up then get in touch.

Regarding the infection, I can certainly remove it from your system but there is no way I can decrypt your files.  And if you have the malware removed then there will probably be problems trying to decrypt them even though you've paid out the ransom (assuming they were honest enough to respect your transaction and give you the private key)


How to Avoid Problems

Computers get infected.  Fact.  But they don’t need to!  Another fact!
In this short article I look at some of the ways things go wrong by focussing on what you can do to avoid it happening!

Keep Windows up to date with any security updates

I’m only interested in security updates - those critical patches that come through with monotonous regularity from Microsoft fixing errors they’ve found in their software.  The problem is that these security holes are also known to hackers and they can make use of them to cause havoc on your computer.  ALSO, if you use Internet Explorer, make sure that has any available security patches applied.

Avoid dubious websites

This includes gaming sites, porn sites, warez sites, cracking sites and so forth.  If you feel you really need to go to such sites then vdo some research and find out how to remain protected by using a sandboxed browser.

Avoid file sharing sites

These abound and appear to give you ‘free’ software, music and so forth.  Also known as peer to peer (P2P) sites, they include the likes of Limewire, BitTorrent, BearShare and many others.  The downloads you get can often contain viruses, trojans and other malware.  If you really must use these sites then make sure you have cast iron security in place and scan everything thoroughly.

Beware of bundled software

So often when you install something you want, it also installs things you DON’T want!  ALWAYS use the custom/expert install mode and watch out for things it wants to add in to ‘help’ you.  This is how you end up with so many unwanted search bars and get your web home page altered.  Even something as simple as downloading and installing Flash player causes most people to end up installing a McAfee component which they neither need nor want.

Beware of rogue security software

These are programs or web sites which pretend to scan your computer and then tell you how bad things are.  They will, of course, offer to repair things for a fee!  More likely they will be adding malware rather than removing it!

Beware of rogue security PEOPLE!

These are the phone calls you receive claiming to be from Microsoft, Windows, BT, etc and saying that they’ve had a report that your computer has a problem and they can help you fix it.  Just hang up!  None of these organisations will cold call you - they’ve probably not even got your phone number!  Do what they say and you can be some hundreds of pounds worse off or you computer could be made unusable - or both.  If you don’t like to hang up on them, just say you don’t have a computer and they’ll hang up.

Update potentially vulnerable software

This certainly includes Java run time environment which has been revealed as having some serious security holes.  Also if you use Adobe Reader (there are alternatives available), make sure that is up to date.

Don’t allow Autorun to operate on your flash drives

A particular method of infecting you uses the fact that when a device like a memory stick is inserted, it will try and run a process.  This process can have been compromised so it is sensible never to let this happen by turning off the autorun feature.

Consider your passwords

Use strong passwords is always a good ide, which means not using dictionary words and also including special characters and both upper and lower case letters, so ‘password’, ‘fluffy’ or ‘letmein’ are all particularly bad and even trying to be clever with such as L3tM31n isn’t a lot better.  If you encounter a malware infection you should seriously consider changing your passwords.
Many types of malware are designed to steal your private information and this includes passwords and login details to sensitive web sites.
Use a different password for each web site you log in to. Never use the same password on different sites. It may seem like a nightmare trying to remember all those passwords but there are software tools which can store them safely and make them easy to use.
Additionally set your router’s admin password to something secure.

Don't allow programs or hackers privileged access

Don't disable User Access Control (UAC) in Vista or Windows 7/8, Limit user privileges and use Limited User Accounts in Windows XP AND be sure to turn on file extensions in windows so that you can see extensions. Ransomware disguises .exe files as fake PDF files with a PDF icon inside a .zip file attached to the email. Since Microsoft does not show extensions by default, they look like normal PDF files and people routinely open them. A common tactic of malware writers is to disguise malicious files by hiding the file extension or adding spaces to the existing extension as shown here (click Figure 1 to enlarge) so be sure you look closely at the full file name.

Be aware of email scams

Know how to recognize Email scams and do not open unsolicited email attachments as they can be dangerous and result in serious malware infection. For example, Zbot/Z-bot (Zeus) is typically installed through opening disguised malicious email attachments which appear to be legitimate correspondence from reputable companies such as banks and Internet providers or UPS or FedEx with tracking numbers. Once infected, Zbot downloads and executes CryptoLocker Ransomware as a secondary payload. CryptoLocker will encrypt all your data files using a Public and Private key pair. Once the encryption of the data is complete, decryption is usually not feasible and your personal data is lost forever unless you pay the ransom.

Backup

It is also a good practice to make a disk image with an imaging tool (i.e. Acronis True Image, Drive Image, Ghost, Macrium Reflect, etc.). Disk Imaging allows you to take a complete snapshot (image) of your hard disk which can be used for system recovery in case of a hard disk disaster or malware resistant to disinfection. The image is an exact, byte-by-byte copy of an entire hard drive (partition or logical disk) which can be used to restore your system at a later time to the exact same state the system was when you imaged the disk or partition. Essentially, it will restore the computer to the state it was in when the image was made.