A recent rash of computer crimes suggests that attackers are becoming more aggressive in their consumer attacks.

The U.S. Securities and Exchange Commission reports a surge in the number of complaints it is receiving about account break-ins by hackers in the last few months. "We've had more investigations in this area than we've ever had before," said John Stark, chief of the SEC's office of internal enforcement, in comments to reporters earlier today.

Stark's comments come on the heels of a report by the U.K.'s Metropolitan Police Computer Crime Unit that it had recovered credit card information and passwords stolen from 2,300 users in backdoor attacks by a U.S. attacker. "Identity theft by computer viruses is on the increase," said a spokesman from the unit.

The financial account attacks and the backdoor attacks both represent a new, more intrusive sort of exploit by identity thieves. Instead of phishing and waiting to steal select bits of information that might be useful in a crime, these new attacks allow perpetrators to go directly into the user's computer to find sensitive data or clean out the user's financial accounts.

In the case of online brokerage accounts, attackers are using spyware and keyloggers to steal account data, just as most phishers do. But instead of just taking the data, they actually enter the customer's account and sell all of the securities, funneling the proceeds to intermediary accounts where the money can be laundered, according to SEC officials.

In other cases, the perpetrators use the online accounts to "pump up" a certain stock. They buy up stock from a group of smaller companies, then sell all the stock in the account and use the proceeds to buy more stock from those same companies, in an effort to send share prices higher.

"When the price gets high enough, [the perpetrators] take profits out of a separate, unaffiliated account," said John Walsh, associate director and chief counsel at the SEC's Office of Compliance Inspections and Examinations in a speech earlier this month. "This is a clever fraud, because it avoids all of the back-end controls" brokerages have in place to prevent fraud.

Like brokerage account theft, the back door attacks uncovered in the U.K. last week suggested a more intrusive type of thief. Instead of waiting to steal personal information in transit over the Internet, the perpetrator introduced a virus that made it possible to search the victims' machines.

U.K. police said they found personal information belonging to some 83,000 British consumers on a single PC found in the U.S. Investigators do not know how far-reaching the attack was, but they said the data would have been enough to allow an attacker to clean out a customer's bank account.

Experts and researchers agree that end users are becoming more frequent targets for attackers because their systems are generally the easiest to penetrate. A BBC study published last week indicates that the average home PC in the U.K. is attacked around 50 times per night. Other studies suggest that consumers are among the most attractive and least-educated targets on hackers' lists. (See Hackers Target Consumers.)

SEC and U.K. law enforcement agencies offered few new tips on defending against these more intrusive attacks. Users should update their antivirus applications, deploy firewalls, and keep an eye on their accounts for suspicious activity, they said.

— Tim Wilson, Site Editor, Dark Reading