Hackers have launched a large-scale spam attack masquerading as CNN.com news notifications about the Israeli invasion of Gaza, security researchers said Thursday, in a repeat of a massive campaign last summer that also posed as CNN alerts.

Wednesday morning, RSA Security Inc.'s FraudAction Research Lab spotted the first messages in the new attack, which take advantage of the ongoing conflict in Gaza. Israeli ground forces entered Gaza on Jan. 3 after several days of airstrikes and naval bombardments that began Dec. 27.

The messages, said Sam Curry, vice president of product management at RSA, pose as alerts from the CNN cable news channel, and promise "graphic and striking" images about the conflict in Gaza between Israel and Hamas.

"It starts off with phishing e-mail that tries to look like CNN," said Curry, "and then the social engineering aspect kicks in. The messages tries to get you to go to a Web site that looks like CNN.com. There, the [fake] site says you must update to Adobe Acrobat 10." Accepting the download delivers a Trojan to the PC instead.

"The Trojan is an 'SSL' stealer," added Curry. "It scrapes the disk and looks for traffic to and from known financial services."

Other security companies reported the campaign, and said the attack is growing very quickly. MX Logic Inc., for example, said that it had seen a major jump in attack volume Thursday.

Early Thursday, said Sam Massiello, vice president of information security at MX Logic, traffic spiked to a pace of about 80,000 messages per hour. "It peaked this morning, around 10 a.m. Mountain [Standard Time], but it dropped pretty quickly after that," said Massiello. "Now, it's holding steady at around 15,000 to 20,000 messages an hour."

Massiello noted the similarities between the newest attack and one conducted in August 2008, when MX Logic monitored more than 160 million messages in a 48-hour period. So far, the current campaign is much smaller. "It's nowhere near the volume of August," he said. "But remember, it took about three days for that attack to really ramp up."

In a posting to the MX Logic blog earlier Thursday, Massiello listed some of the subject lines that the bogus CNN messages use, including "Hamas launching rocket war after Gaza evacuation," "Hamas Goads Israel into War" and "War in Gaza: while Israel and Hamas fight."

"They're trying to look topical," said RSA's Curry.