Microsoft Corp issued software to fix 31 security flaws in its programs, a single-day record for the company whose products are targeted by hackers because they sit on the vast majority of computers.

The patches repair vulnerabilities in Windows, Office and Internet Explorer, as well as key pieces of software that businesses use in their data centers.

Once hackers are alerted to such vulnerabilities, they quickly start developing malicious software to exploit them. Such programs can be used for cybercrimes such as identity theft, sending spam and taking control of computer systems.

Alerting hackers to the flaws presents a challenge for businesses as they need time to test the patches before installing them on their computer systems. They need to make sure that the new software does not interfere with existing programs because patches can sometimes cause systems to crash.

Patching will be especially challenging for enterprises, said Dave Marcus, a senior researcher with McAfee Inc, the world's No. 2 security software maker.

It will be easier for consumers to address the threat as they can quickly download patches over the Internet, easily eliminating their exposure to attack. Such patches rarely cause stand-alone PCs to crash.

(Reporting by Jim Finkle; Editing by Steve Orlofsky)