Ad serving network DoubleClick confirmed Friday that hackers had attempted to breach the security of the company's computer systems.
The company said it was aware of the attacks and had to shut down some of its servers to investigate. Service was disrupted temporarily during the shutdown.
“While the attempts to access our systems appear to be mischievous in nature, we take seriously any attempt to compromise the security of our systems,” said Jules Polonetsky, DoubleClick's chief privacy officer. “We do not believe that there has been any serious impact to our networks but are working aggressively to ensure the integrity of our systems.”
The problem surfaced when French online magazine Kitetoa.com reported it had discovered a security flaw on a DoubleClick Web site.
In its statement, DoubleClick did not specify the source of the intrusion attempt. However, Attrition.org, which claims it maintains the largest archive of Web site defacements, recorded the defacement of a DoubleClick-owned Web site on March 28 by hackers claiming to be associated with the group Prime Suspectz.
The hackers broke into the site — login.dartmail.com, a private site requiring a password for access — and replaced the page with the message, “prime suspectz owned one of doubleclick servers hohohooohhoho.”
In November, Prime Suspectz, which in the past claimed to be located in Brazil, began a campaign of defacements against 21 international Web pages of high-profile companies.