Extremist groups, including Saudi dissident Osama bin Laden's network, are using popular web sites to post encrypted messages to their agents plotting guerrilla activities, security sources said on Tuesday.
The Internet has become the medium of choice among many guerrilla groups to pass on hidden messages, replacing the classified columns in newspapers that Cold War-era spies used to deliver their secrets.
"This is warfare on the cheap and very easy to activate," said Yonah Alexander, head of the International Center for Terrorism Studies at the Potomac Institute for Policy Studies.
Internet bulletin boards carrying pornographic and sports information - which get huge numbers of "hits" - are among the most popular hosts for extremist groups such as bin Laden's, said cyber-intelligence expert Ben Venzke.
Bin Laden, a dissident Saudi businessman, has been indicted for the 1998 bombing of two U.S. embassies in East Africa and has been named as a possible suspect behind last fall's bombing of the USS Cole destroyer in Yemen. Four alleged bin Laden associates went on trial Monday in federal court in New York for the embassy bombings.
USA Today newspaper reported on Tuesday that bin Laden began using encryption five years ago, but recently increased its use after U.S. officials revealed they were tapping his satellite telephone calls from Afghanistan, where he lives.
BUSY BULLETIN BOARDS ARE POPULAR TARGET
Venzke said just as the recipient reading a coded classified ad would know what to look for, a secret message could be embedded, or encrypted, in an image seen by millions on an Internet bulletin board.
He cited the example of a pornographic picture labeled 'blond bombshell' posted on an Internet bulletin board which would probably be downloaded by thousands of users who were unaware of a coded message "hidden" in the existing image.
"The cell (guerrilla), though, will download that image, know what program to run to extract it, what encryption software to use to decrypt it and then will have that information," said Venzke, director of intelligence, special projects, at iDefense cyber-intelligence company in Virginia.
Venzke declined to name sites where material is being hidden but said any bulletin board or public forum that generated lots of traffic was a target.
"Because it's done on a heavily-used public bulletin board, it's extremely challenging and difficult to track," he added.
Security experts said some messages are scrambled using free encryption programs set up by groups that advocate privacy on the Internet, which are then decrypted using a code known only by the recipient and sender.
CIA WORRIED ABOUT USE OF INTERNET
One U.S. security official said the authorities were extremely worried about the use of the Internet by extremist groups and that this was an area being watched very closely.
In testimony to Congress last year, the CIA's information operations issue manager, John Serabian, said Middle East groups such as Hizbollah, Hamas and bin Laden's, were using computerized files, email, and encryption to support their organizations.
"We also recognize that cyber tools offer them new, low-cost, easily hidden means to inflict damage. Terrorists and extremists already use the Internet to communicate, to raise funds, recruit, and gather intelligence," he said.
CIA director George Tenet also addressed the issue in a closed hearing last year when he referred to millions of potential "information warriors".
Extremist groups now routinely send their operatives for training on how to manipulate the Internet for plotting attacks, security sources said.
"Some groups are sending their people to study computer engineering. What is of grave concern here is the motivation behind these groups and their capability," said Alexander.
Alexander suggested that the government should devote more attention to fighting this problem, which he said was becoming more sophisticated by the day.