Sunday, 9 June 2013

Fighting off the zombies!

Zombies are clearly very popular in books, on TV, and in movies and games. But they are spreading! Just recently, I’ve been hearing about zombie computers, zombie companies, and zombie everything else. So, I thought I’d take a look at this rise of the zombies!

So, let’s start with zombie computers. These look like ordinary Internet-connected computers, but they’re used to spread e-mail spam and launch distributed denial-of-service (DDOS) attacks. Unlike their movie counterparts, zombie computers don’t look any different. What’s happened is that the user has typically downloaded a virus or a trojan that has allowed a hacker to take control of their computer. The user continues, probably unaware, to use their machine, and the hacker can take control and get it to send spam e-mails, or try to access a designated Web site at a specified time. The only good news about a zombie laptop is that it can be revived (see a qualified technician to do so), and by using firewalls and antivirus software, further attacks can be prevented.

Quite different are zombie companies. These are companies that are struggling to stay afloat. They can just about afford the interest payments on their loans, but not much more. They are generating just about enough cash to service their debt, so the bank is not obliged to pull the plug on the loan. And so the company limps along, but it doesn’t have enough money to invest.

There are also zombie households. They have interest-only mortgages, which they can afford to pay the interest on, but they are unable to pay off the loan itself.

Then there’s zombie data. This is described as old forgotten data that you thought you’d deleted, but hadn’t. The trouble with this kind of data is that it could be accessed by hackers and could be used against you. People are likening it to data that you thought you’d thrown away, but someone sorts through your trash and finds it – and then uses it to perhaps access your system. We’re talking about old laptops that are given to charities without the hard drives being wiped, or data stored in the cloud in an account that isn’t much use any more – it’s forgotten, but not actually gone. Dormant files can be a danger!

Zombie programs are the programs that hackers use to gain access to your computer. They are often calls ‘bots’. And a series of linked zombie computers is a botnet.

I’m also sure that there are plenty of zombie programs sitting on mainframes and other platforms that were written years ago to perform important tasks and were never deleted. They’re sitting there – perhaps their existence is unknown to the current sys progs – waiting for someone to execute them. Perhaps, with all the changes that have taken place in the intervening years, they can do no harm. Or, perhaps they can cause mayhem! It might be worth checking that any of these zombie programs can’t come back and cause chaos.

You get zombie processes on Unix. These are processes that have completed execution, but they retain an entry in the process table – allowing the parent process to read its child’s exit status. Usually all entries are removed once the parent process has read the information it needs. You can identify a zombie using the ps command – it puts a ‘Z’ (for zombie) in the STAT column.

You can get zombie transactions in SqlTransaction code. With this, a zombie transaction is a transaction that cannot be committed (due to an unrecoverable error) but is still open.

COBOL is sometimes described as a zombie programming language because, no matter what else happens in programming languages, it’s always there – seemingly unkillable! In fact, IBM has recently announced the IBM Enterprise COBOL for z/OS V5.1 compiler.

Perhaps there are more zombies out there than you thought!
Next time, I’m definitely not talking about vampire and werewolf computing.

No comments: