Threat Lab

The past couple of days have been very busy for a lot of people, following the announcement by Microsoft that they had discovered a new network worm called Morto. After reading the refreshingly thorough writeup about Morto from both Microsoft and our partner Sophos, we were surprised to find that a few of our customers had been infected — and cleaned up — beginning with some poor schlub in South Africa as early as July 23rd, but the worm kicked into high gear last Thursday and began to propagate rapidly.

But, as much as the technical details in these posts are useful for researchers and analysts, they don’t really get to the heart of how a user of an infected computer would be affected by the worm. So, after spending a bit of time infecting some of my own machines these past couple days, I wanted to share my hands-on experience with you.

Bottom line, the worm was written to spread to (and infect) the computers run by people who don’t take security seriously: It copies itself to other computers by trying to Remote Desktop into those computers using a list of what can only be described as completely moronic passwords (the full list is on Microsoft’s technical writeup about the worm). The repurcussions are that people (or companies) who use poor quality, easily guessed passwords have been (or are going to get) spanked by Morto, and then they’ll be really irritated at the (reversible but obnoxious) changes the worm makes to the behavior of the infected computer.

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An unusual family of Trojans, apparently of Chinese origin, engages in rootkit-like behavior which seems designed not to hide the presence of the malware on an infected system, but to misdirect or confuse a technical person who might be using system analysis tools on an infected computer.

The Trojans all originated from a server operated by a free Web host in China, and each sample we tested sent profiling data about the infected system to a command-and-control server located on yet another free Web host, also located in China. It appears to have capabilities to receive instructions to download other components, and it scans the system for antivirus products commonly available in China, including products made by Qihoo 360, China’s largest homegrown antivirus company.

But the most interesting aspect of the Trojans was how it managed to fool most of the free tools someone might use to monitor running programs. The Trojan shows up in the list of active programs, but when that list includes a full path to the running executable, that path points at a nonexistent file supposedly in another location. read more…

FireEye’s Lanstein and Wolf speak at Black Hat

I’ve worked in the security industry for nearly five years, and it was apparent early on that the most successful people in this field bring to their work a passion and a commitment to protecting not only one’s customers, but to providing a certain level of information about security threats to the world at-large, so even your non-customers can help or protect themselves.

It can be hard to know where to stop once you get on a roll. Malware infections frequently lead to unexplored, interesting backwaters on the Internet. And, sometimes, those backwaters are where the criminals run those operations. When I stumble upon a criminal network or a botnet controller, it simply doesn’t feel like I’ve done enough when I merely add signatures which block or remediate infections and communications with a command-and-control server from Webroot customers. If malicious behavior depends on one or more Internet sites that send instructions, my (and many others’) initial reaction is we need to shut that down, permanently. But sometimes, a too-rapid reaction can blow back in your face.

Obviously, that was also the case when Alex Lanstein and Julia Wolf of internet security firm FireEye stumbled upon the Rustock botnet. At one time, before law enforcement in several countries swooped in on the data centers hosting the botnet’s command-and-control (CnC) infrastructure in a coordinated raid earlier this year, the massive network of Rustock-infected computers was responsible for about half of spam flooding the ‘net. The researchers’ instincts to engineer a takedown of the botnet sounded very familiar, but their initial attempts to do so backfired, and may have even spurred the malware developers to change their game, and may have made it more difficult, eventually, to eliminate the CnC altogether.

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A serious, targeted threat from customized malware that steals credit card magnetic strip track data could literally bankrupt your business. That’s the message two security researchers from Trustwave gave at their talk during the Defcon computer security conference Saturday.

The researchers, Jibran Ilyas and Nicholas Percoco of Trustwave Spider Labs, respond to calls for help when businesses find malware in critical systems. When banks field reports of credit card fraud, they try to find the earliest common location or business where all the victims used their card. When they do, the bank calls the business, who then call in the researchers.

In their talk, Malware Freak Show 3, the researchers reported on several types of malware all of which are designed to steal the so-called Track 1 data — the information encoded on the magnetic strip on the back of the card — when a salesperson or waiter swipes the credit card attached to the cash register.

The malware may reside on the register (a device that, in many cases, is simply a custom-configured Windows computer) or on a server in the back room of the business that’s used to process credit card transactions. Once the malware has the Track 1 data, it transmits the string of numbers to remote locations, where the data can be used to produce fake, but functional, physical credit cards. The thieves can then sell or use the cards to purchase valuable merchandise.

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By Marco Giuliani

In our previous technical analysis of the ZeroAccess rootkit, we highlighted how it acts as a framework by infecting the machine — setting up its own private space in the disk, first through a dedicated file system on the disk, and more recently by using a hidden and locked directory. This is where the rootkit stores the modules it downloads from the command and control servers. Until now, the plugins we’ve monitored have been ad-clickers and search engine hijackers.

We have also noted how the ZeroAccess rootkit acts very similar to the TDL3 rootkit, either by infecting a random system driver, using its own file system to store its plugins or by filtering the disk I/O by analysing the SCSI packets – though in a pretty different way. It’s more effective in the TDL3 rootkit and less effective in the ZeroAccess rootkit, however ZeroAccess has many more self-protection mechanisms in place.

While analyzing the ZeroAccess rootkit, I’ve always had the feeling it was inspired by the TDL3 rootkit. But while looking at the latest updates of it I’ve found something pretty interesting: The ZeroAccess team is looking at TDL rootkit as an enemy that needs to be defeated. The questions remains, is there a link between the two rootkits? We suspect the answer is yes.

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The Black Hat briefings, held Wednesday and Thursday this week, once again brought together some of the best and brightest in the security industry to share knowledge about novel attacks and better defenses against old and new attacks. And, once again, there were some eye opening moments at the conference.

Right from the beginning, it was clear the scope of the conference had shifted from the previous year. Conference founder Jeff Moss described a new, more rigorous committee-driven process that Black Hat had begun to employ to scrutinize and vet talk proposals. Talks this year would be more technical, go deeper into security threats, and would encompass a broader range of topics than had been done in years past.

But soon after Moss introduced former ambassador and CIA counterterrorism expert Cofer Black, the opening keynote speaker to the conference, someone pulled a fire alarm in the hall where the speech was taking place. While lights flashed and warning sirens sounded, Black joked about the prerecorded messages playing over loudspeakers.

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There are fewer types of malware infections more frustrating and annoying than a rootkit with backdoor capabilities. Over the past couple of years, we’ve seen the emergence of this new, tough-to-fight infectious code, and its transformation from nuisance to severe threat.

With the hard work and perseverance of Threat Research Analyst and master reverse-engineer Marco Giuliani, we’re proud to release the latest build of a tool we’ve used internally to clean the infections from the notable ZeroAccess rootkit off of victims’ computers. AntiZeroAccess exploits many of the vulnerabilities that Marco discovered in the rootkit to cleanly remove the rootkit code from infected machines.

The free tool removes the rootkit but does not restore the Access Control Lists (ACLs) that have been modified by the rootkit. For that, you’ll probably want to use a free tool like SetACL, which can make software functional that ZeroAccess disabled by modifying its ACL.

As I do every year, I’ve deliberately traveled to the most inhospitable climate zone in the continental US — that is, the city of Las Vegas — to attend the elite technical conference known as the Black Hat Briefings.

Black Hat is not just a technical conference, but a kind of calling for its attendees, which brings together experts in computer security, privacy, and attacks with high level officials in government and industry. In this rarefied environment, the security industry and its benefactors share information, tools, and techniques that help the entire industry coordinate their work against the interests of criminals, spies, and the vast numbers of Internet ne’er-do-wells.

I’ll be reporting from the conference about cool tools, new information about attacks, and deep analysis of malware all week. On Friday, the conference switches gears to become Defcon, which is a little less formal, a little less businesslike, and a lot more chaotic and interesting. Stay with us this week as we cover the most interesting conference in the security world.

Late Monday, after news about the death of troubled pop singer Amy Winehouse had been circling the globe for a little more than 48 hours, we saw the first malware appear that used the singer’s name as a social engineering trick to entice victims to run the malicious file. Abusing celebrity names, news, or even deaths isn’t a new (or even particularly interesting) social engineering tactic, but there was one unique aspect to this particular malware’s behavior that raised some eyebrows around here: It appears that Brazilian phisher-Trojan writers seem to be working more closely with their Chinese counterparts, using servers in China as dead drops for their stolen goods.

The widely-reported case of the malware campaign continues to distribute new, randomized files via a download link managed through a dynamic DNS service, more than a week on. The file’s name, in Portugese, (“103684policia-inglesa-divulga-fotos-do-corpo-da-cantora-amy-winehouse-WVA.exe“) translates roughly to English police divulge photos of singer Amy Winehouse’s corpse, but victims who open this file are only going to see their computer become compromised.

The malware modifies the Hosts file in Windows to redirect traffic from 78 different Web sites — the vast majority of which are Brazilian banks and finance sites such as e-gold, with the rest being American Express, and Microsoft‘s Brazilian and US domains for Hotmail, Live, and MSN — to one of 9 IP addresses, almost all of which point to servers hosted in Chinese networks. One oddball outlier IP address in the modified Hosts file list points to an IP address belonging to the network operated by the Ford Motor Company, but that IP address was not allocated to an operational server when I did some tests.

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The criminals who push rogues at the world don’t really care about the reputations of the ISPs or Web hosting services they abuse. They leap from free service to free service until they’ve thoroughly worn out their welcome and, in some cases, destroyed the reputation of the service they abused. But they have behaved in one predictable way over the years: They’re stingy, and won’t pay for anything unless it’s absolutely necessary, despite the fact that they’re raking in cash by the boatload.

But that seemed to change this week when we saw a number of Web sites pop up on the radar. The sites employ the now well-worn scam of pretending to be some sort of video streaming service. In this case, they pretended to be a porn site, but the most surprising part was not what was hosted, but where: Amazon’s Cloudfront hosting service ended up, temporarily for a few hours, serving up malicious Web pages. Amazingly, it seems they actually paid for hosting instead of just stealing it.

Amazon shut the sites down quickly, but before they did, we visited one site called xrvid-porno.com. The page isn’t exactly family friendly, but the gist of the scam is that that page eventually redirected the browser to a server inside of Amazon’s cloud hosting service, and that’s where the trouble began.

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By Marco Giuliani

Among the most infamous kernel mode rootkits in the wild, most of them have had a slowdown in their development cycle – TDL rootkit, MBR rootkit, Rustock are just some examples. The same doesn’t apply for the ZeroAccess rootkit. The team behind it is working quite hard, which we know for a fact because I’ve seen it.

We already talked about this rootkit and its evolutions in several blog posts, along with a white paper that documents more in depth all the technical features of the malware. The last major update released by the team behind ZeroAccess dates back a couple of weeks; That update implemented a strong self-defense routine able to kill security software programs that try to get access to its code, blocking the security software from running by manipulating access control list, or ACL, settings.

Last week ZeroAccess received another update, and again it’s a major one. The rootkit shifted from a hidden encrypted file used as an NTFS filesystem volume to a more comfortable hidden directory created inside the Windows folder, where the rootkit still stores its configuration data and other malware in an encrypted form.
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Last week, threat researcher and malware reverse-engineer Marco Giuliani wrote up a fairly technical description of a bootkit — a rootkit that infects the master boot record of the hard drive, making it very difficult to remove — called Popureb. Marco’s report made it clear that the bootkit does not require Windows users to format the hard drive and reinstall Windows from scratch, as Microsoft had initially claimed was required for victims of this drive-by infection.

Andrea Allevi, one of our developers who works under Marco’s direction, subsequently wrote a tool that can remove the bootkit from an infected computer, which we’re releasing today to the public. We don’t offer technical support for the tool, but it’s fairly straightforward to use: Just launch it on a system infected with Popureb.E, using an account with Administrator privileges. It will ask your permission to clean the infected MBR, and once you say ‘yes’ it’ll do the rest. You’re welcome!