Oracle Corp said it is preparing an update to address a flaw in its widely used Java software after the U.S. Department of Homeland Security urged computer users to disable the program in web browsers because criminal hackers are exploiting a security bug to attack PCs.

BOSTON (Reuters) - Oracle Corp said it is preparing an update to address a flaw in its widely used Java software after the U.S. Department of Homeland Security urged computer users to disable the program in web browsers because criminal hackers are exploiting a security bug to attack PCs.

"A fix will be available shortly," the company said in a statement released late on Friday.

Company officials could not be reached on Saturday to say how quickly the update would be available for the hundreds of millions of PCs that have Java installed.

The Department of Homeland Security and computer security experts said on Thursday that hackers figured out how to exploit the bug in a version of Java used with Internet browsers to install malicious software on PCs. That has enabled them to commit crimes from identity theft to making an infected computer part of an ad-hoc computer network that can be used to attack websites.

Java is a computer language that enables programmers to write software utilizing just one set of codes that will run on virtually any type of computer, including ones that use Microsoft Corp's Windows, Apple Inc's OS X and Linux, an operating system widely employed by corporations. It is installed in Internet browsers to access web content and also directly on PCs, server computers and other devices that use it to run a wide variety of computer programs.

Oracle said in its statement that the recently discovered flaw only affects Java 7, the program's most-recent version, and Java software designed to run on browsers.

Java is so widely used that the software has become a prime target for hackers. Last year, Java surpassed Adobe Systems Inc's Reader software as the most frequently attacked piece of software, according to security software maker Kaspersky Lab.

Java was responsible for 50 percent of all cyber attacks last year in which hackers broke into computers by exploiting software bugs, according to Kaspersky. That was followed by Adobe Reader, which was involved in 28 percent of all incidents. Microsoft Windows and Internet Explorer were involved in about 3 percent of incidents, according to the survey.

The Department of Homeland Security said attackers could trick targets into visiting malicious websites that would infect their PCs with software capable of exploiting the bug in Java.

It said an attacker could also infect a legitimate website by uploading malicious software that would infect machines of computer users who trust that site because they have previously visited it without experiencing any problems.

They said developers of several popular tools, known as exploit kits, used by criminal hackers to attack PCs, have added software that allows hackers to exploit the newly discovered bug in Java.

Security experts have been scrutinizing the safety of Java since a similar security scare in August, which prompted some of them to advise using the software only on an as-needed basis.

At the time, they advised businesses to allow their workers to use Java browser plug-ins only when prompted for permission by trusted programs such as GoToMeeting, a Web-based collaboration tool from Citrix Systems Inc.

Java suffered another setback in October when Apple began removing old versions of the software from Internet browsers of Mac computers after its customers installed new versions of its OS X operating system. Apple did not provide a reason for the change and both companies declined to comment at the time.