A guide to spam

A British internet company is being used by one of the world’s most prolific spammers to produce billions of unwanted e-mails, The Times has learnt.

Unsolicited messages have increased by up to 300 per cent over the past four months as criminal gangs step up their attempts to contact computer users.

The gangs have secretly taken control of up to one in twelve computers in British homes. The machines are being used to send out thousands of e-mails every day promoting prescription drugs, cheap shares, money- laundering schemes and even wives.

Experts estimate that spam now accounts for 90 per cent of the 50 billion e-mails sent each day. Although more than 95 per cent of the unsolicited messages are detected by anti-spam systems, there is still an enormous quantity reaching e-mail inboxes. To increase the chance of reaching computer users the spammers are adopting “image” messages to avoid detection by anti-spam systems that check text. They have also developed the most aggressive virus yet seen to control computers without the owners’ knowledge.

Amichai Inbar, identified as the world’s fifth most significant spammer, has been using a London-based internet company to control the networks of hijacked computers, The Times has discovered. He is responsible for billions of e-mails advertising pornography, drugs such as Viagra and offers of “cheap” shares that turn out to be virtually worthless.

Mr Inbar, a Russian who also uses the names John Che Blau and Jonathan Blau, operates from Tel Aviv, Israel, but is linked to spammers in Russia and the US.

He is believed to have gained control of up to 150,000 computers that he uses to send his own spam, or rents out the network to criminal gangs based in Russia and the US.

Steve Linford, who runs Spamhaus, a spambusting organisation, and works with law enforcement agencies in Britain and abroad, said that Mr Inbar was being investigated by the FBI and Israeli police. “Israeli law enforcement has been on to the gang operation from the UK ISP (internet service provider) for some time and is warning for UK law enforcement to get involved,” he said.

Eighty per cent of the spam is controlled by 200 gangs involving 500-600 professional spammers. Ten spammers, based mainly in Eastern Europe, are responsible for most of the messages.

The massive increase in spam has been partially linked to the spread of the Stration virus via e-mail this summer. Once a computer has been infected it automatically contacts the spam operator’s system for instructions. It and thousands of other hijacked machines create a network called a botnet that is used to send hundreds of millions of spam e-mails every day. The botnet can also be used to mount “denial of service” attacks — inundating a company with millions of e-mails so that its computer system crashes. The gang will then demand a payment to halt the attack. Because the hijacked computers within the botnet are constantly changing, with an additional 600,000 machines infected each day, it is increasingly difficult to block messages.

To help to bypass anti-spam protection the gangs are increasingly sending their messages as picture files that look like text. “Image spam” now accounts for a third of all unwanted messages. It has a file size five times bigger than a normal text-based message — 20kB compared with 4kB. It uses random dots and dashes or tiny images to fool spam detection programmes.

British authorities appear to be powerless to stop an influx of spam. Neither the Information Commissioner nor the police have brought a prosecution under anti-spamming laws.

Anthony Smyth, technical manager of the internet security company Marshal, said: “It is an arms race. On one side we are trying to stop the spam and on the other you have the spammers trying to exploit weaknesses in the system.”

Most of the infected computers are home PCs because they are less likely to have the latest security programmes. Anti-spam companies now issue updates every 30 minutes in an attempt to keep up with the spammers.

The spam e-mails often have innocuous titles to encourage recipients to open them. The e-mail security firm Postini says the messages that have caused problems in the past year included “Donald Trump wants you”, “Please respond” and “It’s Lisa. I must have sent you the wrong site”.

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