Targeted phishing attacks against high-rollers reached new heights over the last two months, according to a study by iDefense.
The VeriSign security division recorded 66 instances of so-called whaling attacks between February 2007, around the time fraudsters adopted the tactic, and June 2008. More than one in four of these assaults happened during the last two months.
Whaling attacks typically use carefully tailored lures in personalised emails designed to trick senior executives into downloading malicious code. Thereafter crackers use compromised machines to gain access to sensitive data such as corporate banking credentials or customer databases. Attacks are frequently timed to coincide with diary events such as tax day. Fraudulent emails have appeared under the guise of the Better Business Bureau, Internal Revenue Service and the Department of Justice, for example.
Matt Richard, director of rapid response at iDefense, explained that fraudsters typically used unscrupulous "bullet proof" hosting services to host malicious code. After tracking the crooks for months, iDefense managed to get access to their control panel, providing an insight into the fraudsters' network.
VeriSign reckons over 15,000 corporate targets have been duped by the approach over the last 15 months. Victims include conglomerates, government agencies, financial institutions and legal firms. Reported victim losses can top $100,000.
The vast majority of these attacks - 95 per cent - are the work of only two groups, according to VeriSign. Each group is differentiated by the attack code it uses. One uses Browser Helper Objects (BHO) to log SSL encrypted sessions or to carry out man-in-the-middle attacks on two-factor authentication systems. Another group favours the use of key logging software.
The latter group is from Romania and Italy, based on the language used in the code and the patterns of fraudulent transactions associated with its activities. The other group is more international, with contacts in China and south east Asia.
iDefense advocates a mixture of staff training and URL filtering as the best defences against the whalers. It warns that the attack approach is only likely to become more common over coming months. "Awareness and education are the best defences against this growing fraud," said iDefense's Richard. ®