A phishing attack that appeared to be an email card from the White House was an attempt to steal documents and other data from government workers -- particularly those involved in computer crime investigations, according to news reports.

According to an Associated Press report, attackers used the e-mail to collect sensitive law enforcement data. No classified information was compromised, officials told AP.

The red holiday e-mail card, with its brightly decorated Christmas tree, prompted recipients to click on a link, which would then download Zeus malware for stealing passwords, the AP report says.

The targeted attack then downloaded a second payload that is designed to steal documents from the recipient's computer, accessing Microsoft Word and Excel files.

Researchers who studied the attack say it was small and targeted to a limited number of groups with law enforcement, military, and government affiliations. It might have been sent out manually in order to avoid detection, the researchers told AP.

In his blog, Alex Cox, a researcher at NetWitness, suggests the attack could be the work of the same attackers who launched the "Kneber" exploit last February.

"It's not surprising that the holiday season was again used as an opportunity to take advantage of end users' naivete by sending a holiday e-card they could not resist opening," says Andy Hayter, anti-malcode program manager at ICSA Labs. "It is apparent that additional education needs to be conducted, since many recipients took the bait and clicked on a malicious link leading to becoming infected with a Zeus trojan horse malware." The systems infected were not running the latest anti-malware protection with the latest signature levels, Hayter observes.

Researchers told AP the attackers stole "at least several gigabytes" of data. One U.S. official told AP the code was "rather poorly written." The hackers could only get easily accessible documents and not those filed deep within layers of folders on the hard drive, said the official, who spoke to AP on condition of anonymity.

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