Sneaky Blackmailing Virus That Encrypts Data

BaCa writes "Kaspersky Lab found a new variant of Gpcode which encrypts files with various extensions using an RSA encryption algorithm with a 1024-bit key. After Gpcode.ak encrypts files on the victim machine, it changes the extension of these files to ._CRYPT and places a text file named !_READ_ME_!.txt in the same folder. In the text file the criminal tells the victims that the file has been encrypted and offers to sell them a decryptor. Is this a look into the future where the majority of malware will function based on extortion?"

Re:Anti-Malware Response

[pclminion]

Uh, if 1024-bit RSA was broken, the world of encryption security would collapse (at least for the short term). Could it happen? Sure, it's possible. Will it happen in time to save your pr0n collection? Highly unlikely.

For one thing, compromise of RSA encryption would render SSL useless.

This has been done before

[mrbill1234]

This same thing happened in the late 80's (or maybe early 90's). Some hackers mailed a 5.25 inch floppy with some "free" software on it to thousands of people around the world. When you installed the software, it would hijack your PC and encrypt various files and you had to pay a ransom to get it back. There was a EULA and everything with the disk (which of course nobody read) which made it clear what would happen if you installed the disk. Perhaps someone can remember what it was called.

Re:LET'S HOPE SO

[Osurak]

Nah, the scammers will just route it through some mule, like they do with the stuff they buy through credit card fraud.

Re:This has been done before

[mrbill1234]

Ok, I googled it:

The Aids information disk:

http://www.jahewi.nl/malware/ransomware/ransomware.html [jahewi.nl]

Re:But were they smart, or stupid?

[nine-times]

Does it matter? I have backups.

Really, this doesn't scare me very much. Can these people stop making money on spam, please, and let them try their hand at blackmail? Because it's fine-- a lot of people won't pay, and others will get the FBI to trace the money to the criminals behind it. They'll probably get caught, but either way they won't get me. Like any sane person, I have a firewall, don't open random attachments, and keep backups.

Re:This has been done before

[gad_zuki!]

This was done recently, perhaps two or three years ago. I believe it encrypted everything in My Documents and asked for payment to unencrypt it. Turns out they used the same key every time. Article from 2006 here.

http://news.bbc.co.uk/2/hi/technology/5038330.stm [bbc.co.uk]

The magic key is:

mf2lro8sw03ufvnsq034jfowr18f3cszc20vmw

Re:But were they smart, or stupid?

[Crazy Taco]

Unless you have space for infinite backups, his method is write. At some point, you'll run out of space and have to delete old backups to make room for the new ones.

Re:Anti-Malware Response

[AmiMoJo]

The last version was eventually "cracked", because the virus used the same key for all the encrypted files so once someone paid up they could distribute the key.

Re:But were they smart, or stupid?

[kesuki]

"And how often do you roll through your backups? "

try 'never i use 1 time recordable optical media'

i realize some people use 'rewritable' media for backups, and have this 'roll over' issue, but the only part of my backup that does rollover is the redundant external HDD for 'critical' data that i don't trust entirely to a DVD media, even is i only buy grade 1 media...

I don't have a small data set either, I have over 1 TB of stuff on optical discs, but surprisingly only about 30 gigs that is important enough to go to a redundant hdd.

Re:This is why backups are good

[Penguinisto]

Not 100% sure... In theory you;re correct (that is, no OS is 100% safe from such a thing), but in practice, it would be almost trivial to defend against. It wouldn't take much to rig a partition full of vital stuff as read-only, then carefully going over any data you want backed up to it once a week or so (remount it read-write for long enough to do the backup, then remount it back to read-only. No sweat. You still have that window of opportunity, but you'll likely find out that your non-protected data got horked long before you open your archives to back things up to 'em).

Also, this is one of the benefits of a journaling filesystem (or in OSX, "Time Machine"), among other things. Roll it back, and *poof* - no more encrypted files.

/P

Re:But were they smart, or stupid?

[SanityInAnarchy]

Given properly rolling backups, you don't just keep dailies for the past month. You keep dailies for a week, and weeklies for a month, and monthlies for however long you have space for.

And given that most people work in files which are essentially text or the moral equivalent (Word docs, etc), it's likely that you do, in fact, have enough space for a very, very large number of backups.

Re:But were they smart, or stupid?

[Carnildo]

And how often do you roll through your backups? Will you notice the encrypted files in time, or will you end up backing up the worthless files instead?

I don't know about most people, but my backups bear a strong resemblance to a versioned filesystem: it doesn't matter if the encrypted files wind up on the backup, because I can always roll back to a version before they were encrypted.

data ransom != blackmail

[Deanalator]

This is data ransom, not blackmail.

Re:Only an idiot doesn't backup.

[SanityInAnarchy]

Bundling rollback inside a filesystem is one of the stupidest things that could be done to fs.

Ok, you're right that the GP is stupid -- no filesystem a desktop user runs will have that transparent rollback. The closest might be "volume shadow copy", but I think that has to be done explicitly for every change you want to record.

But seriously, have you looked at FUSE lately? There's a filesystem for everything... And, historically, there are log-structured filesystems, which can, indeed, roll back any change that hasn't already been overwritten. That approach has nothing to do with inodes -- in fact, not all filesystems even have inodes.

A little knowledge is a dangerous thing.

Version control software and/or backups are designed for this purpose - and are filesystem agnostic (work with whatever fs suits your needs).

As a philosophy, yes, they're FS agnostic. In reality, it depends very much on which you choose. What you probably want is incremental backups -- version control is nice, too, but it's mostly to protect you from yourself.

Re:Anti-Malware Response

[kesuki]

Fortunately, brute force attacks aren't necessary. If one can read the memory space used by the 'decryptor' one can find the key in seconds.

this is why movie content will 'never' be immune to cracking. in the case of this virus, the decryptor is sent to you over the internet, if you pay the money, but having a good backup scheme also defeats the need to brute force. having a good security setup, should negate even the need for backups to prevent infection in the first place.

so always have a competent hardened firewall device like smoothwall express, never download attachments (webmail helps a lot in this arena, along with a secure browser, and a phishing aware user/browser add-on) avoid windows like the plague, but if you must run windows make sure it can only get access to the actual ports of the programs you actually use on it. and never run as administrator, unless you really genuinely need to do something that can't be done as a normal user.

trusting a 'commercial' 'hardware' router to protect a windows machine is insane, even if you've replaced the firmware with some variant of linux, it's Still Not hardened like smoothwall...

fine if you have all linux/bsd machines, but windows has as much security as the emperor had new clothes, even with a $$$ security suite. sad but true, only 0% of tested windows security software could stop 50/50 2006/2007 known rootkit/malware post install... the best was i think being able to remove 7/50 and 13/50, if it had actually gotten installed. specialized tools were also tested, not just suites.

the point being, if you must run windows remember that a piece of paper stands more chance of surviving a nuclear blast at point blank than windows has of being de-rooted without a format.

   

Re:But were they smart, or stupid?

[LurkerXXX]

An important part of the backup process is to occasionally test the backups to make sure that they can be restored properly. corrupted backups suck, but do happen. I test my personal ones pretty regularly. I test my work ones on a set schedule. You should too.

Actually it's called Ransomware

[ewhenn]

http://en.wikipedia.org/wiki/Ransomware_(malware) [wikipedia.org]

The crypting your files and extort has been around since 1989 http://en.wikipedia.org/wiki/PC_Cyborg_Trojan [wikipedia.org]

Re:But were they smart, or stupid?

[Opportunist]

Allow me to tell you how the money trail on this works:

You are asked to send money through Western Union or some other provider that doesn't check your ID for amounts smaller than a few thousand USD. Then they send some bum to one of the thousand WD offices, somewhere on this planet, with the withdrawal code. And only once they get your money, you get your decryption key.

So, now you know where the money ends up, and why police can't do jack about it.

1024-bit RSA is NOT considered secure anymore

[this great guy]

As it was pointed out by another poster, no 1024-bit RSA is not sufficiently strong. Recent papers have demonstrated that factoring a 1024-bit key is now within practical reach. See for example this PhD dissertation from a student whose advisor was Shamir (the S in RSA FYI), which estimates that cracking a 1024-bit key would cost a few million US dollars [mit.edu].

Sure, at this point only a small number of organizations have a few million dollars to spare on cracking RSA, but this is beyond the point. The flaw is sufficiently serious that security standards are now recommending 2048-bit RSA keys minimum.

What I am talking about are relatively recent developments, it is not very well-known that 2048-bit is the minimum recommended length. This is why 1024-bit keys are still wildly used everywhere. My bank (www.wellsfargo.com) uses a 1024-bit key...

Re:But were they smart, or stupid?

[Duncan Blackthorne]

And only once they get your money, you get your decryption key.

"And only once they get your money, you don't get your decryption key."

There, fixed that for you. :-)

Re:But were they smart, or stupid?

[computerman413]

No, Western Union discontinued telegrams 2 years ago [livescience.com]

Re:Anti-Malware Response

[Mr Z]

Oops, I see you said "decryptor." Of course, if you have that, then you've unlocked this key. But, how many keys does the virus have on its keyring and how quickly does it acquire more? It's not like it's a DVD, fixed in a medium or a CSS descrambler ASIC in a $20 DVD player.

Oh please! We all know there aren't any REAL banks

[falconwolf]

in Nigeria?

There are real banks in Nigeria, owned by the ruling ethnic group, that's where the billions of dollars from oil goes. The rulers get their money while those who live where the oil comes from, the Niger Delta [realclearpolitics.com], have to fight for scraps.

Falcon

Re:But were they smart, or stupid?

[SanityInAnarchy]

In MSFT's and even OS X time machine the default settings are to backup everything, the OS, applications etc.

News flash: There are more than two backup programs in the universe.

for a home users that is just stupid.

When was the last time you saw a home user reinstall an entire OS? How many home users still have all the application CDs needed?

For that matter, these are also things which don't change a lot. They shouldn't take up too much space in the backup, if you're using even a halfway-intelligent backup program -- both of the ones you mentioned at least do hardlinks.

The real danger here would be if the program actually corrupted the entire backup repository. For that to happen, it would have to know when your backup hard drive was plugged in -- and there are other ways of avoiding this, such as running backups over a network to a server with limited access.

Re:All your dataz

[Anonymous Coward]

Joe User: Someone set up us the encryption. We get no data. Readme file turn on.
Jack Hacker: How are you gentlemen? All your data are belong to us.

Corporate Linux users generally *do* pay

[CustomDesigned]

The self-support model that is required for a zero-price Linux distro is often not acceptable in a corporate environment (unless they have internal IT that can provide the support). Which is why Red Hat Linux (and Suse and Oracle) continue to sell despite the existence of Centos. The best part is - while the price is non-zero (and generally too hefty for home use), the freedom is still included.

Re:1024-bit RSA is NOT considered secure anymore

[this great guy]

Damn. 2000 bits of binary... Every single bit added to a binary key does exponential increases to the resulting protection.

This is a common mistake that non-cryptographers make. The above is true only for symmetric algorihtms. For asymmetric ones, like RSA, this is false. A 2001-bit RSA key is not twice harder to crack than a 2000-bit key. This is why for example the NIST recommendations list different key lengths depending on the type of crypto (sym vs. asym). For introductory-level material I suggest Cryptographic key length [wikipedia.org].

Re:Corporate Linux users generally *do* pay

[mlts]

The main reason for this is that it requires cash on the barrelhead for security certifications like FIPS, Common Criteria, etc.

RedHat and Novell have anted up to the table and can offer Linux desktops and servers in an industry that pretty much was Windows only, other than maybe a Solaris or AIX box here and there. Part of what people pay for when purchasing commercial support for RHCE or SUSE is the cost of this.

OBMac: MacOS 10 too has recently gotten FIPS certified, so that is another UNIX that is usable on the desktop where the certificates are needed for due diligence.

RedHat is great on servers, should something need changed, I can load the SRPM, make in-house source code changes, then have those stored separately from the original source so it can be documented come audit time what was changed in some program that needed customization on that level. To boot, with the binary RPM, all it takes is one simple command to push the change out to relevant machines via ssh and have those boxes install it.

No, the future is either...

[istartedi]

...easy-to-use backups, and/or the government tracking down the payments and busting the guy who receives it.

Of course, if you are just backing up to the hard drive, the virus will make sure to trash your backups. Better back up to a non re-writeable CD. Most people's unique data isn't that large. If it is, you should be doing nightly offsite backups anyway.

Re:Vista solution?

[cbhacking]

I was waiting for somebody to mention this. Shadow copies, also known as Previous Versions, is a great way to undo this kind of thing (at least long enough to take a backup before reformatting, unless you're 100% sure you can purge all the malware). It's worth mentioning that they are also on Windows Server 2003/2008.

So, the answer is yes, but only for a limited time. The number of shadow copies that can be kept is determined by the "free" space on the drive. On the other hand, there's usually at least several revisions there, so if the folder isn't changed often you can probably find the old version. If the folder IS changed frequently, you'd probably notice right away.

I say folder because if a file's name is changed (or a file is deleted), you need to recover it by going to the folder's shadow copy and restoring from there (you can restore the whole folder, but can also extract individual files). You can also rename the file and check for shadow copies under its original name.

Finally, don't forget that the shadow copies can be deleted. It takes more than normal permissions - I don't think even normal Administrators can delete them directly, though if you have Administrator it's easy enough to get System - which means you would need to have approved a UAC prompt somewhere - but that's true of most software installation. That said, the actual attack (encrypting personal files) requires no special permissions at all - it would work even on a properly locked-down Linux or OS X box. IE under Protected Mode wouldn't have sufficient permissions, however.

Re:But were they smart, or stupid?

[stokessd]

Slow down junior...

OS X is reasonably secure, but so is Linux. And while harder, Windows can also be made that way. Just because your Mac hasn't been pwned yet doesn't mean that it won't. The only secure OS is one that doesn't do anything.

Macs are actually 24 years old, and there were Mac OS viruses out there. The hardware features of automagically reading a floppy inserted into the drive made the spread of those viruses much more easy.

Sheldon

Re:But were they smart, or stupid?

[Jason Levine]

They could send the decrypt code via e-mail... from an account they hacked into. Or they could send it via mail. Only first it would go to an "innocent" (in that they don't know what they are doing) relayer. The relayer gets a big envelope, opens it up and takes out a smaller envelope. The relayer buys stamps for that envelope (they are promised reimbursement from the "small overseas business" they think they are working for) and sends it out. Even if you trace it to the relayer, you'll be hard pressed to make it any further than that.