Cyberespionage malware targets U.S., other countries

MiniDuke uses rigged PDF files to exploit an Adobe Reader vulnerability patched this month

A cyberespionage operation that uses well-crafted PDF documents to trick recipients into opening the malicious files has targeted government entities and institutions in 23 countries, including the U.S., security vendors reported Wednesday.

The malware used in the spy operation, dubbed MiniDuke, was created as recently as Feb. 20, an indication that the attackers are still active, said Kaspersky Lab, which uncovered the criminal activity with its partner CrySyS. The cyberspies' location and identity is not known.

Targets of the attackers included 59 institutions and government offices. In the U.S., victims included think tanks, a research institute and a healthcare provider, Kaspersky said.

The security companies named the malware MiniDuke because it reminded them of Duqu, another data-gathering app that some researchers have linked to Stuxnet. Discovered in 2010, Stuxnet was used to damage centrifuges in Iran's nuclear facilities. The U.S. and Israeli governments developed the malware, according to media reports.

Despite some similarities, there's no evidence MiniDuke is connected to Duqu. Nevertheless, the newly discovered malware has some interesting characteristics.

For one, the attackers targeted recipients with malicious PDF files containing fabricated content designed to appeal to the recipients' interests. The documents included human rights seminar information, Ukraine's foreign policy and membership plans for the North Atlantic Treaty Organization (NATO).

"To compromise the victims, the attackers used extremely effective social engineering techniques," Kaspersky's Global Research & Analysis Team said in a blog post

The files were rigged to exploit an Adobe Reader vulnerability patched this month. FireEye had discovered the previously unknown flaw Feb. 12. The vulnerability, which is in Adobe Reader versions 9, 10 and 11, enables an attack to bypass the software's sandbox.

Another interesting element is in the way the malware makes contact with its command and control servers. The app drops into the victim's hard drive a downloader that is only 20KB in size, is unique for every computer and contains a customized backdoor. The downloader uses a set of mathematical calculations to determine the host's unique fingerprint and then uses that data to encrypt its communications.

Once installed, the malware heads to Twitter in search of specific tweets in accounts created by the attackers. The tweets include tags with encrypted URLs that provide access to the C&C servers, which upload additional backdoors disguised as GIF picture files.

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If Twitter is not working or the accounts are taken down, the malware uses Google search to find encrypted URLs. "This model is flexible and enables the operators to constantly change how their backdoors retrieve further commands or malcode as needed," Kaspersky said.

Once the additional backdoors are installed, they fetch a larger backdoor that carries out the cyberespionage activities. Those activities include copying, moving and removing files, making a directory, setting up a kill process and downloading and executing new malware. The backdoor receives instructions from two servers, one in Panama and the other in Turkey.

Countries with government agencies and institutions targeted by the attackers included Belgium, Brazil, Bulgaria, Czech Republic, Georgia, Germany, Hungary, Ireland, Israel, Japan, Latvia, Lebanon, Lithuania, Montenegro, Portugal, Romania, Russian Federation, Slovenia, Spain, Turkey, Ukraine, United Kingdom and the United States.

Cyberespionage is rising as countries and cybercriminals use sophisticated malware to steal valuable information from government entities, institutions and large corporations. While not alone in cyberspying, China is believed to have one of the most extensive cyberintelligence operations. 

Copyright © 2013 IDG Communications, Inc.

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