Blaster II? Microsoft warns of new security holes

Blaster II? Microsoft warns of new security holes

Only weeks after the appearance of the Blaster worm, Microsoft released a software patch for still more holes similar to those Blaster exploited.

The three new vulnerabilities were all rated "critical" and could be used by a remote attacker to take control of vulnerable systems, installing programs or changing data stored on a hard drive, Microsoft said.

The three security vulnerabilities affect the DCOM (Distributed Component Object Model) interface to a Windows component called the RPCSS service. That service processes messages using the RPC (Remote Procedure Call) protocol, according to a Microsoft security bulletin, MS03-039, that describes the problem. (See

All of Microsoft's supported operating systems were affected, except for Windows ME (Millennium Edition), the company said. Malicious hackers could exploit the vulnerability by creating a program to send improperly formatted RPC messages to the RPCSS service on a vulnerable machine.

Those messages could cause a buffer overflow that would enable attackers to place and run their own computer code on the machine, Microsoft said.

The security holes are "very similar" to a vulnerability disclosed in July in bulletin MS03-026, according to Jeff Jones, senior director of Trustworthy Computing security at Microsoft. (See

Code to exploit that vulnerability appeared on the Internet shortly after the release of the MS03-026 security bulletin. Within weeks, an Internet worm using that exploit code, W32.Blaster, was released, infecting hundreds of thousands of computers worldwide.

The patch also covers the earlier RPC hole and supersedes that earlier patch. Microsoft now recommends customers apply MS03-039 instead of the MS03-026 patch, Jones said.

To prevent a similar occurrence with the new RPC vulnerabilities, Microsoft is encouraging customers to use firewall software to block access to unnecessary communications ports such as those used by Blaster.

Home users should also enable the automatic update and automatic install features on Windows XP and other Windows operating systems, which would automatically download and install the new patch, Jones said.

A special Web page contains information on better securing Windows systems, he said. (See

For enterprise customers and others who need more technical information about the new vulnerabilities, Microsoft released an updated network scanning tool that can identify vulnerable Windows systems. The company will also host a webcast today. (See

The vulnerabilities were discovered internally, as well as by independent security companies, including eEye Digital Security.

The new findings were the result of increased scrutiny of Windows code used to handle RPC since the discovery of the earlier RPC DCOM vulnerability by a Polish hacking group, the Last Stage of Delirium Research Group, Jones said.

Microsoft didn't know of any attacks that used the vulnerabilities, Jones said.

He declined to comment on whether current versions of the Blaster worm might be modified to exploit the new vulnerabilities.

"I don't want to speculate about different ways that people might try to exploit these vulnerabilities," he said.

Follow Us

Join the newsletter!


Sign up to gain exclusive access to email subscriptions, event invitations, competitions, giveaways, and much more.

Membership is free, and your security and privacy remain protected. View our privacy policy before signing up.

Error: Please check your email address.
Show Comments