Experts: New attacks may exploit latest Windows flaws

Malicious attacks attempting to take advantage of the three critical flaws announced Wednesday by Microsoft in several versions of its Windows software shouldn't be long in coming, according to security experts.

Because the vulnerabilities are very similar to the one that the Blaster worm took advantage of last month, it will take relatively little effort for copycats to churn out variants attacking the new holes, they said. "This new vulnerability is reminiscent of the first RPC flaw and should be treated with the utmost urgency and priority by network administrators globally," said Marc Maiffret, co-founder of eEye Digital Security in a statement.

The security vendor was one of the companies to discover the new flaws.

"This is RPC and Blaster all over again, with new patches required and a strong potential of new variants of the original Blaster worm emerging," Maiffret said.

The flaws exist in the remote procedure call (RPC) protocol used by the Windows operating system. The first two are buffer-overrun vulnerabilities that could allow an attacker to take full administrative control of a victim's system. An attacker that exploited these flaws would be able to take a variety of actions, including installing malicious programs, deleting data or creating new accounts, according to Microsoft.

The third flaw is a denial-of-service vulnerability that could allow RPC services to hang and become unresponsive, according to Microsoft.

The U.S. Department of Homeland Security (DHS) also warned about the possibility that exploits would soon be released. The agency yesterday issued an advisory warning users of the “potential for significant impact on Internet operations” because of the vulnerabilities.

“DHS believes that exploits are being developed,” the advisory said.

In urging users to update vulnerable Windows versions a soon as possible, the DHS also added that it's “concerned that a properly written exploit could rapidly spread on the Internet as a worm or virus in a fashion similar to the Blaster worm.”

It isn't very difficult to develop exploits for the new holes, said Max Caceres, director of product management at Core Security Technologies, a Boston-based vendor of security software and services. For instance, Core Security was able to write attack code capable of compromising systems in the manner described by Microsoft in a matter of hours after the bulletin was announced, Caceres said.

"In this case, it was pretty fast because the vulnerabilities are very similar to the last one," Caceres said. "The attack vector is exactly the same. The only change is in where the vulnerabilities exist.

"We always assume that if we can do it, there are others out there who can do it," said Dan Ingevaldson, engineering manager in the X-Force unit at Internet Security Systems (ISS) in Atlanta.

ISS was able to develop an exploit for the previous RPC vulnerability within 12 hours using just the information gleaned from the patch Microsoft issued to handle with the flaw.

With the latest flaw, hackers already have an existing code base with which to work, security experts said. As a result, the amount of time administrators usually have to test and patch their systems before a malicious exploit is crafted will be shorter than usual, predicted Jerry Brady, chief technology officer at Guardent in Waltham, Mass.

"There's a lot of exploit code available for the last RPC vulnerability that would only require very small modifications" to be effective against the new flaws, he said.

In addition, there are some automated tools, including one called KaHT, that can be relatively easily modified to scan for and exploit vulnerable systems, Brady said.

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