According to the NIPC advisory, "Chinese hackers have publicly discussed increasing their activity" between April 30 and May 7. Those days coincide with several dates of historic significance in China, including May Day, Youth Day and the two-year anniversary of the accidental bombing of the Chinese Embassy in Belgrade, Yugoslavia, on May 7.
To date, pro-Chinese hackers have defaced dozens of U.S. Web sites, replacing existing content with pro-Chinese or anti-U.S. rhetoric, according to the FBI and security experts. In addition, NIPC analysis of an Internet worm named Lion that is infecting computers and installing distributed denial-of-service tools on various systems shows that the worm sends password files from the victim site to an e-mail address in China.
Security consulting firms have also uncovered what some experts are calling a potentially massive Internet reconnaissance and surveillance operation originating in China that is looking for vulnerable Domain Name System (DNS) servers in the U.S. Those operations have been under way for several weeks, they said.
While responding on April 7 to a reported intrusion at a law firm in New York, experts at Defendnet Solutions Inc., a managed security services firm in Providence, R.I., said they uncovered evidence of a large China-based reconnaissance operation potentially involving dozens of computers.
Ed Schernau, a product manager at Defendnet, said the law firm began receiving an influx of DNS scans that were "regular and consistent" and continued at a rate of one every six minutes. Although DNS exploits are common on the Internet, Schernau said Defendnet is confident that the attackers "were probably scanning higher blocks of networks to see what was out there and were probably scanning every network address owned by a particular ISP."
In addition, Schernau said a profile of the source machine was consistent with what he called "a giant firewall device" and that it is conceivable that there were many machines behind the attack.
Shafer Ramsey, a security engineer at Defendnet who responded to the incident, said the company's counter-reconnaissance operation on the attacker was unable to produce any solid leads on the attacker's identity. "In this case, the attacker was a black hole," said Ramsey. "They used a self-signed certification on their system, providing them total control over their Net presence."
The level of sophistication of the methods used in this incident is consistent with a "top-notch" hacker or even a government organization, said Ramsey.
Chris Rouland, director of the X-Force vulnerability research unit at Internet Security Systems Inc. in Atlanta, said his company has detected a significant increase in the number of scans and probes coming out of China. "[Remote procedure call] scanning has certainly increased dramatically over the last six weeks," said Rouland, adding, however, that the scans are originating in places other than China.
The only U.S. government site believed to have been defaced so far by Chinese hackers is the Navy's Executive Office for Acquisition Related Business Systems, according to an intelligence report issued this week by Vigilinx Inc., a New York-based security firm. The Chinese hacker threats are a direct response to a pro-American hacker campaign called "ChinaKiller," according to the Vigilinx report. Pro-U.S. hackers have defaced hundreds of Chinese sites since April 4, the report states.
Vigilinx urges all U.S. companies and government agencies to run vulnerability tools, such as SATAN, SARA, Nessus and SAINT, against their systems. In addition, Common Gateway Interface (CGI) vulnerability tools should also be run to detect vulnerable CGI scripts on Web servers, the Vigilinx report said.