WASHINGTON — U.S. authorities eyed North Korea on Wednesday as the origin of the widespread cyber attack that overwhelmed government websites in the United States and South Korea, although they warned it would be difficult to definitively identify the attackers quickly.
The powerful attack that targeted dozens of government and private sites underscored how unevenly prepared the U.S. government is to block such multipronged assaults.
While Treasury Department and Federal Trade Commission websites were shut down by the software attack, which lasted for days over the holiday weekend, others such as the Pentagon and the White House were able to fend it off with little disruption.
The North Korea link, described by three officials, more firmly connected the U.S. attacks to another wave of cyber assaults that hit government agencies Tuesday in South Korea. The officials said that while Internet addresses have been traced to North Korea, that does not necessarily mean the attack involved the Pyongyang government.
The officials spoke on condition of anonymity.
South Korea intelligence officials have identified North Korea as a suspect in those attacks and said that the sophistication of the assault suggested it was carried out at a higher level than just rogue or individual hackers.
U.S. officials declined to discuss publicly who may have instigated the intrusion or how it was done.
Targets of the most widespread cyber offensive of recent years also included the National Security Agency, Homeland Security Department and State Department, the Nasdaq stock market and The Washington Post, according to an early analysis.
The cyber assaults are known as “denial of service” attacks. Such attacks against websites are not uncommon and are caused when sites are so deluged with Internet traffic that they are effectively taken off-line. Mounting such an attack can be relatively easy and inexpensive, using widely available hacking programs.
The cyber attack did not appear, at least at the outset, to target internal or classified files or systems, but instead aimed at agencies’ public sites, creating a nuisance for officials and the consumers who use them.
Officials agreed that the incident brings to the forefront a key 21st-century threat. “It tells you that cyber attacks are real,” said Rep. Dutch Ruppersburger, D-Md., who was briefed on the incident. “It’s a very serious problem and one of the more serious facing us, along with terrorism. And China and Russia are the main threats.”
In North Korea
