Wednesday, April 1, 2009

Conficker.c State of Art worm Attacking millions of PC

oh yeah. The worlds most creative, a state of art worm is going to attack your pc soon.

The copied quotes from TREND MICRO is below.

"These guys have no designs, I think, on taking down the infrastructure, because that would separate them from their victims," said Paul Ferguson, a threat researcher at antivirus vendor Trend Micro, calling the technology and design of Conficker.c as "pretty much state of the art."

Exactly how many computers are infected with Conficker.c is not yet known, but it's one of the largest botnets ever seen and users aren't out of the woods yet

An expected activation of the Conficker.c worm at midnight on April 1 passed without incident, despite sensationalized fears that the Internet itself might be affected, but security researchers said users aren't out of the woods yet.

"They want to keep the infrastructure up and in place to make it much harder for good guys to counter and mitigate what they've orchestrated," he said.

Conficker.c was programmed to establish a link from infected host computers with command-and-control servers at midnight GMT on April 1. To reach these control servers, Conficker.c generates a list of 50,000 domain names and then selects 500 domain names to contact. That process has started, researchers said.

Exactly how many computers are infected with Conficker.c is not yet known, but the estimated number of systems infected by all variants of the Conficker worm exceeds 10 million, making this one of the largest botnets ever seen.

While infected computers have started reaching out to command servers as expected, nothing untoward has happened.

"We have observed that Conficker is reaching out, but so far none of the servers they are trying to reach are serving any new malware or any new commands," said Toralv Dirro, a security strategist at McAfee Avert Labs, in Germany.

This may just mean the people who control Conficker are biding their time, waiting for researchers and IT managers to relax their guard and assume the worst is over.

"It would be pretty stupid for the guys running Conficker to use the first possible opportunity, when everybody is very excited about it and looking at it very carefully," Dirro said. "If something was going to happen, it would probably happen in a couple of days."

Time is not on Conficker's side. The worm can be easily detected and removed by users. For example, if a PC is unable to reach Web sites such as,, or that is an indication that the computer may be infected.

In addition, IT managers can easily spot traffic coming from odd domain names and block access to the computers on their company networks. "The longer criminals wait, the less infected hosts they've got," Dirro said.

Additional help comes from a loose coalition of security vendors and others called the Conficker Working Group, which has banded together to block access to domains that Conficker is trying to communicate with. But it's not immediately clear whether those efforts, which have been successful at blocking earlier versions of the worm, will be effective against the activation of Conficker.c.

"We can't really say how successful the attempts at blocking them or not routing them are," Dirro said. "That's something we'll see when the first domain actually starts serving malware, if at least one starts doing that."

Despite the uneventful passing of the activation deadline, the threat presented by Conficker remains real.

"These guys are very sophisticated, very professional, very determined and very measured in how they implement and make changes to things," Ferguson said, adding that Conficker.c is better defended and more survivable than previous versions of the worm. "This activation on April 1 was probably just arbitrary and picked to cause hysteria."

At some point, the people behind Conficker.c could try to generate revenue from the botnet they've created or they could have other intentions.

"The big mystery is that there's this big loaded gun out there, this network of millions of machines that's under the control of persons unknown," Ferguson said. "They've given no indication of what their motives are other than toying with people."

-------- So what we should do now ? Read on.

Conficker is a work of malware that, in the form of multiple variants, has been worming its way through unpatched Windows desktop and server machines for the past four months.

Conficker has garnered mainstream attention of late due to an April 1 trigger that researchers have identified in the most recent variant of the worm. On this date, it appears that Conficker-infected machines will change the way that they "phone home" to fetch new code and instructions from whomever holds the worm's reins.

In October 2008 Microsoft released a fix for the vulnerability that Conficker exploits, in a patch that Microsoft deemed critical enough to release outside of its typical Patch Tuesday schedule. Still, enough Windows machines have remained unpatched for Conficker to spread to what security researchers estimate to be millions of machines.

Presumably, the goal of Conficker's controllers involves the creation of a botnet that would carry out illegal machine-based activities by proxy, but there's no telling exactly what the worm's makers have in mind.

The prescription for Conficker prevention is prompt system patching (particularly when Microsoft singles out a fix for out-of-band distribution), combined with client firewall and antivirus software for blocking the worm's activities and detecting and eliminating the malware where it surfaces.

In addition, members of the security community have prepared a set of freely available tools to aid in Conficker detection and removal for infected systems on your network.

More broadly, Conficker calls attention to the problems inherent in deploying client systems that offer up network-facing services to anonymous nodes, and highlights the importance of watching more closely the privileges granted to the system-level applications that run on mainstream operating systems.

Moreover, because Windows Vista and Windows Server 2008 machines have proven to be significantly less vulnerable to Conficker than systems running Windows 2000, XP and Server 2003, the worm also highlights the very real consequences of stepping off the so-called operating system upgrade treadmill. For all its hardware refresh requirements, potentially unwanted feature adjustments and software incompatibility wrinkles, Vista includes security enhancements that blunted the effect of Conficker on unpatched systems.

It's up to companies to consider whether to interpret all of this as a call to approach Windows upgrades--and their associated costs--with greater alacrity, or to step up evaluation of OS alternatives, such as Linux, with less upgrade friction and a better defined roadmap around trusted OS technologies.

How Does Conficker Work?

Conficker's primary means of propagation involves exploiting a buffer overflow vulnerability in Windows' Server system service, which is responsible for, among other things, enabling the sharing of local resources, such as disks and printers, with other machines on a network.

Conficker exploits this vulnerability to execute code on Windows systems, without requiring a system's user to open any file or visit any particular Web site--and without regard to whether a user is running with administrative or limited privileges.

Windows 2000, XP and Server 2003 are particularly vulnerable to Conficker because the affected Server service on these systems is configured to permit access from anonymous users. In October 2008, Microsoft provided information on removing the ACL (access control list) entry that permits this anonymous access, but since the ACL involved is hard-coded into the Windows DLL, this access modification would have had to be made after every boot.

With Windows Vista, Windows Server 2008 and the development builds of Windows 7, the vulnerable service limits access to authenticated users by default, but enabling the no-password file-sharing option on these systems would restore anonymous access--and vulnerability to Conficker.

Unpatched Windows XP SP2, Vista and Server 2008 machines shipped out-of-the-box with Windows' firewall enabled to block the vulnerable RPC (remote procedure call) interface, but the common firewall exception that enables file and print sharing opened the door to Conficker. Even with a firewall exception, however, Vista and Server 2008 machines would allow access to the vulnerable service only from other machines in the same network zone. For instance, sharing a resource on a Private network would not permit access to Conficker-infected nodes.

Firewall and service authentication requirements aside, Windows Vista and Server 2008 worked to mitigate Conficker infection with Address Space Layout Randomization, which, combined with the Data Execution Protection functionality introduced in XP SP2, makes it significantly more difficult to exploit buffer overflow vulnerabilities such as the one targeted by Conficker.

What Now?

Beyond the RPC vulnerability that got Conficker cooking, later variants of the worm added the capability to propagate through network shares and over infected USB memory sticks by taking advantage of Windows' Autorun functionality. Also, once Conficker has successfully rooted itself on a machine in your network, the malware will attempt to spread to other machines on the network by launching a dictionary-based attack to guess logins and passwords.

As a result, even assuming that you've long ago applied the Microsoft patches to block the Windows service vulnerability, it's important to keep watch for Conficker on your network.

Most security suites are prepared to detect and remove instances of the worm, but it’s also worth checking out the set of six Conficker containment tools prepared by Felix Leder and Tillmann Werner of the Honeynet Project and available for free download at the Web site of the University of Bonn.

The tools include a utility for calculating the list of domains that Conficker generates for fetching further code and instructions from its controllers; a memory disinfector that terminates running Conficker processes on an infected system; and a utility for calculating the file names and registry keys under which Conficker hides itself on a particular system.

Also available is a simple Python-based network scanner capable of detecting Conficker machines on a network. The scanner accepts as input either a range of IP addresses or a text file of addresses to scan, and returns a status of “clean,”” infected” or “blocked” for systems it manages to reach on the network.

Interestingly, the tool set also includes a Conficker vaccination tool that runs as a service on Windows systems and, if contacted by the worm, reports its status as up-to-date. This tool, while perhaps not appropriate for production use, is certainly an interesting take on approaching the Conficker conflict.

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