Web security experts say the silence is likely calculated to avoid giving any credit to hackers that thrive on limelight and to reduce the risk of any further exposure.
"You don't want to pump up the attacker," said Dave Marcus, director of security research at McAfee Labs, an Internet security company in Santa Clara, Calif. "When you're a big brand and you're already a target, you certainly don't want to give them any more press than is necessary."
A collective of anonymous hackers known as Lulz Security - the same outfit that said it was behind a breach that compromised millions of user accounts at Sony Corp. in April - claimed credit for the attack on the Connecticut chapter of InfraGard, an FBI partner organization that shares information among the agency and state organizations.
FBI officials in Connecticut and Washington, D.C., have declined to comment beyond confirming an attack that prompted a shutdown of the website as a precaution.
Robert Kenny, the president of InfraGard Connecticut, also refused to describe the extent of any damage. He said the website had limited information about members but did not provide further details.
In one hint of the potential exposure, Lulz claimed via Twitter that passwords stolen from InfraGard allowed them to take control of RECOL, a Branford, Conn.-based Internet provider. The company declined to comment.
InfraGard is an association of businesses, academic institutions and law enforcement agencies dedicated to sharing information to prevent hostile acts against the United States, according to its website. Business representatives who participate get access to security information from government sources such as the FBI and Department of Homeland Security and can participate in discussions with others in the IT-security field.
Hackers also stole 180 passwords from members of InfraGard's Atlanta chapter in an attack earlier this month. Lulz released those passwords online for anyone to see.
No such data has been released from the Connecticut attack, although Lulz said recently they would release a "payload" of information from their leaks and breaches on Friday. In addition to the breach of Sony's PlayStation Network, the hackers say they are responsible for attacks on government websites in Brazil, the CIA webpage and the U.S. Senate computer system.
Organizations sometimes wait to talk about security events until after they have fixed their issues, Marcus said. Statements from organizations that have been breached can open them up to more attacks.
The hackers, in contrast, have not been shy to boast of their exploits. Lulz has taken credit for defacing the PBS website after it aired a documentary seen as critical of WikiLeaks founder Julian Assange, and a manifesto released by the group earlier this week called for a united hacker "war" and encouraged "any vessel, large or small, to open fire on any government or agency that crosses their path."
Described by critics as anarchic delinquents and supporters as Internet freedom fighters, the group is a freeform organization without a clear rationale behind their attacks.
Alan Paller, director of research at the Internet security training school SANS in Bethesda, Md., said a hacker's love of the spotlight can be his undoing. The FBI uses basic police skills to identify hackers' communications, he said.
Investigators are starting to put pressure on Lulz. On Wednesday, British police filed hacking-related charges against a teenager suspected of ties to Lulz.
The group denied via Twitter that the 19-year-old was part of its operations, but the increased scrutiny and criticism from other hacker organizations have led to infighting and a shift in the Lulz's typically cheery tone.
The group's Twitter feed recently released the names and addresses of hackers they accused of assisting investigators.
"Snitches get stitches," said the statement from the organization.
"Your cold jail cell will be haunted with our endless laughter," the group wrote.