The Flame malware is at least four years old and hosted its command-and-control servers on more than 85 domain names, according to an analysis by Kaspersky
After collaborating for a week on an analysis of Flame’s infrastructure, Russian security firm Kaspersky Labs and domain-name service provider OpenDNS reported that they had discovered at least 85 domains registered over the last four years that were used to host the command-and-control servers associated with Flame. The first three domains were registered on 2 March, 2008, according to OpenDNS.
Most of the domains start with a string of characters that appear innocuous, such as banner, flash, dns or server. By constructing the names with common words, the attackers tried to make it less likely that communications between infected machines and the command-and-control servers would be blocked, Dan Hubbard, vice president of research for OpenDNS, said during a press conference on 4 June.
“It was very well-planned and very well-executed, so it is a very sophisticated attack from that perspective,” said Hubbard.
The first analyses of Flame were published by Kaspersky Labs, Symantec and other security firms in late May, after Iran’s Computer and Emergency Response Team gave copies of the malware to the firms. Computers infected by the program were found in Iran, Lebanon, Syria, Sudan as well as other nations in the Middle East and North Africa.
Signs of infections were also found in European countries and the United States, but security experts that have analysed the program believe it did not necessarily target those nations.
Hours after the security firms published their initial research, the Flame command-and-control infrastructure was pulled offline, ostensibly by its operators, Roel Schouwenberg, senior researcher with Kaspersky Labs, told reporters. The company used sinkhole servers, which captured communications meant for Flame’s command-and-control infrastructure, to tap into the network of infected computers.
20 domain registries involved
In the latest analysis, OpenDNS and Kaspersky Labs found that some 20 domain registries were used to register the more than seven dozen domains. In addition, while the domains constituted the main command-and-control channel used by Flame’s operators, another communications channel between compromised systems may exist, such as a peer-to-peer network, Schouwenberg said.
“We noticed that some victims are connecting with newer-version information over the past week,” said Schouwenberg. “So even though the command-and-control infrastructure was down, the victims’ machines were somehow updated.”
The analysis of domain registration activity, performed in conjunction with domain registry GoDaddy, underscored the differences between Flame and two previous attacks, Stuxnet and Duqu.
The command-and-control servers used by the Flame operators all ran Ubuntu Linux, while Stuxnet and Duqu both used CentOS for their operations. The Duqu operators were “super-stealthy” in hiding the Internet addresses of the actual computers serving up malware and commands, while the Flame operators ran their control scripts from the servers at each domain.
“From this point of view, we can state that the Duqu attackers were a lot more careful about hiding their activities compared to the Flame operators,” wrote Aleks Gostev, a senior lab expert with Kaspersky.
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