The U.S. Department of Labor's Web site was hacked on Tuesday. Malicious code was placed on the site in the process.

According to security Relevant Products/Services information and event management firm AlienVault, the government site has been serving out malicious code since Wednesday. That code then works to install malware on victim computers. The Labor Department could not be reached immediately but news reports indicate the hack has been resolved.

Some security firms are pointing the finger at DeepPanda, a Thai non-governmental organization with a human rights mandate. DeepPanda has been connected with a number of advanced persistent threat Relevant Products/Services attacks.

Behind the Hack Attack

Andrew Brandt, director of Threat Research at Solera Networks, said although he was not sure what time the Labor Department site was modified, he he was made aware Tuesday that code that was suspicious in appearance had been uploaded to the department's "Site Exposure Matrices" (SEM) Web site.

"The page is offline at the moment, and I had never heard of the SEM before, but the SEM page described it as 'a repository of information gathered from a variety of sources regarding toxic substances present at Department of Energy (DOE) and Radiation Exposure Compensation Act (RECA) facilities," Brandt told us.

"The code that was added to the foot of the page caused a site visitor to load a script hosted on a server elsewhere. The page loaded the script from a page at the domain dol.ns01.us -- but the ns01.us domain is actually owned by a dynamic DNS Relevant Products/Services service called ChangeIP.com. The domain name pointed to a server hosted in Los Angeles, as of last night."

What Was the Motive?

Among the malicious code pushed down to victims' computers was a binary data Relevant Products/Services file with a .png extension. Brandt didn't manage to obtain this file through visiting the site. Instead, another researcher provided the file. That researcher claimed this binary file was the initial malware payload of the attack Relevant Products/Services.

According to Brandt, upon execution, the malware tried to contact another ChangeIP.com dynamic DNS hostname -- microsoftUpdate.ns1.name. As of this morning, he explained, that hostname had been blackholed and the malware has been unable to "phone home" since.

"It's difficult to discern the intent of a criminal targeting visitors to such a specific Web site, but clearly this was planned well in advance, and was not intended to reach a wide audience of potential victims," Brandt said. "The reality is that the public, and possibly even the webmasters at the Labor Department, may never know who carried out the attack or why, or just how successful it was."