Entries Tagged "malware"

Page 38 of 49

Interview with an Adware Developer

Fascinating:

I should probably first speak about how adware works. Most adware targets Internet Explorer (IE) users because obviously they’re the biggest share of the market. In addition, they tend to be the less-savvy chunk of the market. If you’re using IE, then either you don’t care or you don’t know about all the vulnerabilities that IE has.

IE has a mechanism called a Browser Helper Object (BHO) which is basically a gob of executable code that gets informed of web requests as they’re going. It runs in the actual browser process, which means it can do anything the browser can do—which means basically anything. We would have a Browser Helper Object that actually served the ads, and then we made it so that you had to kill all the instances of the browser to be able to delete the thing. That’s a little bit of persistence right there.

If you also have an installer, a little executable, you can make a Registry entry and every time this thing reboots, the installer will check to make sure the BHO is there. If it is, great. If it isn’t, then it will install it. That’s fine until somebody goes and deletes the executable.

The next thing that Direct Revenue did—actually I should say what I did, because I was pretty heavily involved in this—was make a poller which continuously polls about every 10 seconds or so to see if the BHO was there and alive. If it was, great. If it wasn’t, [ the poller would ] install it. To make sure the poller was less likely to be detected, we developed this algorithm (a really trivial one) for making a random-looking filename that was consistent per machine but was not easy to guess. I think it was the first 6 or 8 characters of the DES-encoded MAC address. You take the MAC address, encode it with DES, take the first six characters and that was it. That was pretty good, except the file itself would be the same binary. If you md5-summed the file it would always be the same everywhere, and it was always in the same location.

Next we made a function shuffler, which would go into an executable, take the functions and randomly shuffle them. Once you do that, then of course the signature’s all messed up. [ We also shuffled ] a lot of the pointers within each actual function. It completely changed the shape of the executable.

We then made a bootstrapper, which was a tiny tiny piece of code written in Assembler which would decrypt the executable in memory, and then just run it. At the same time, we also made a virtual process executable. I’ve never heard of anybody else doing this before. Windows has this thing called Create Remote Thread. Basically, the semantics of Create Remote Thread are: You’re a process, I’m a different process. I call you and say “Hey! I have this bit of code. I’d really like it if you’d run this.” You’d say, “Sure,” because you’re a Windows process—you’re all hippie-like and free love. Windows processes, by the way, are insanely promiscuous. So! We would call a bunch of processes, hand them all a gob of code, and they would all run it. Each process would all know about two of the other ones. This allowed them to set up a ring…mutual support, right?

So we’ve progressed now from having just a Registry key entry, to having an executable, to having a randomly-named executable, to having an executable which is shuffled around a little bit on each machine, to one that’s encrypted—really more just obfuscated—to an executable that doesn’t even run as an executable. It runs merely as a series of threads. Now, those threads can communicate with one another, they would check to make sure that the BHO was there and up, and that the whatever other software we had was also up.

There was one further step that we were going to take but didn’t end up doing, and that is we were going to get rid of threads entirely, and just use interrupt handlers. It turns out that in Windows, you can get access to the interrupt handler pretty easily. In fact, you can register with the OS a chunk of code to handle a given interrupt. Then all you have to do is arrange for an interrupt to happen, and every time that interrupt happens, you wake up, do your stuff and go away. We never got to actually do that, but it was something we were thinking we’d do.

EDITED TO ADD (1/30): Good commentary on the interview, showing how it whitewashes history.

EDITED TO ADD (2/13): Some more commentary.

Posted on January 30, 2009 at 6:19 AM • View Comments

The Economics of Spam

Excellent paper on the economics of spam. The authors infiltrated the Storm worm and monitored its doings.

After 26 days, and almost 350 million e-mail messages, only 28 sales resulted—a conversion rate of well under 0.00001%. Of these, all but one were for male-enhancement products and the average purchase price was close to $100. Taken together, these conversions would have resulted in revenues of $2,731.88—a bit over $100 a day for the measurement period or $140 per day for periods when the campaign was active. However, our study interposed on only a small fraction of the overall Storm network—we estimate roughly 1.5 percent based on the fraction of worker bots we proxy. Thus, the total daily revenue attributable to Storm’s pharmacy campaign is likely closer to $7000 (or $9500 during periods of campaign activity). By the same logic, we estimate that Storm self-propagation campaigns can produce between 3500 and 8500 new bots per day.

Under the assumption that our measurements are representative over time (an admittedly dangerous assumption when dealing with such small samples), we can extrapolate that, were it sent continuously at the same rate, Storm-generated pharmaceutical spam would produce roughly 3.5 million dollars of revenue in a year. This number could be even higher if spam-advertised pharmacies experience repeat business. A bit less than “millions of dollars every day,” but certainly a healthy enterprise.

Of course, the authors point out that it’s dangerous to make these sorts of generalizations:

We would be the first to admit that these results represent a single data point and are not necessarily representative of spam as a whole. Different campaigns, using different tactics and marketing different products will undoubtedly produce different outcomes. Indeed, we caution strongly against researchers using the conversion rates we have measured for these Storm-based campaigns to justify assumptions in any other context.

Spam is all about economics. When sending junk mail costs a dollar in paper, list rental, and postage, a marketer needs a reasonable conversion rate to make the campaign worthwhile. When sending junk mail is almost free, a one in ten million conversion rate is acceptable.

News articles.

Posted on November 12, 2008 at 6:52 AM • View Comments

"Scareware" Vendors Sued

This is good:

Microsoft Corp. and the state of Washington this week filed lawsuits against a slew of “scareware” purveyors, scam artists who use fake security alerts to frighten consumers into paying for worthless computer security software.

The case filed by the Washington attorney general’s office names Texas-based Branch Software and its owner James Reed McCreary IV, alleging that McCreary’s company caused targeted PCs to pop up misleading security alerts about security threats on the victims’ computers. The alerts warned users that their systems were “damaged and corrupted” and instructed them to visit a Web site to purchase a copy of Registry Cleaner XP for $39.95.

I would have thought that existing scam laws would be enough, but Washington state actually has a specific law about this sort of thing:

The lawsuits were filed under Washington’s Computer Spyware Act, which among other things punishes individuals who prey on user concerns regarding spyware or other threats. Specifically, the law makes it illegal to misrepresent the extent to which software is required for computer security or privacy, and it provides actual damages or statutory damages of $100,000 per violation, whichever is greater.

Posted on October 2, 2008 at 7:03 AM • View Comments

News from the Rock Phish Gang

Definitely interesting:

Based in Europe, the Rock Phish group is a criminal collective that has been targeting banks and other financial institutions since 2004. According to RSA, they are responsible for half of the worldwide phishing attacks and have siphoned tens of millions of dollars from individuals’ bank accounts. The group got its name from a now discontinued quirk in which the phishers used directory paths that contained the word “rock.”

The first sign the group was expanding operations came in April, when it introduced a trojan known alternately as Zeus or WSNPOEM, which steals sensitive financial information in transit from a victim’s machine to a bank. Shortly afterward, the gang added more crimeware, including a custom-made botnet client that was spread, among other means, using the Neosploit infection kit.

[…]

Soon, additional signs appeared pointing to a partnership between Rock Phishers and Asprox. Most notably, the command and control server for the custom Rock Phish crimeware had exactly the same directory structure of many of the Asprox servers, leading RSA researchers to believe Rock Phish and Asprox attacks were using at least one common server. (Researchers from Damballa were able to confirm this finding after observing malware samples from each of the respective botnets establish HTTP proxy server connections to a common set of destination IPs.)

Posted on September 10, 2008 at 7:47 AM • View Comments

Chinese Cyber Attacks

The popular media conception is that there is a coordinated attempt by the Chinese government to hack into U.S. computers—military, government corporate—and steal secrets. The truth is a lot more complicated.

There certainly is a lot of hacking coming out of China. Any company that does security monitoring sees it all the time.

These hacker groups seem not to be working for the Chinese government. They don’t seem to be coordinated by the Chinese military. They’re basically young, male, patriotic Chinese citizens, trying to demonstrate that they’re just as good as everyone else. As well as the American networks the media likes to talk about, their targets also include pro-Tibet, pro-Taiwan, Falun Gong and pro-Uyghur sites.

The hackers are in this for two reasons: fame and glory, and an attempt to make a living. The fame and glory comes from their nationalistic goals. Some of these hackers are heroes in China. They’re upholding the country’s honor against both anti-Chinese forces like the pro-Tibet movement and larger forces like the United States.

And the money comes from several sources. The groups sell owned computers, malware services, and data they steal on the black market. They sell hacker tools and videos to others wanting to play. They even sell T-shirts, hats and other merchandise on their Web sites.

This is not to say that the Chinese military ignores the hacker groups within their country. Certainly the Chinese government knows the leaders of the hacker movement and chooses to look the other way. They probably buy stolen intelligence from these hackers. They probably recruit for their own organizations from this self-selecting pool of experienced hacking experts. They certainly learn from the hackers.

And some of the hackers are good. Over the years, they have become more sophisticated in both tools and techniques. They’re stealthy. They do good network reconnaissance. My guess is what the Pentagon thinks is the problem is only a small percentage of the actual problem.

And they discover their own vulnerabilities. Earlier this year, one security company noticed a unique attack against a pro-Tibet organization. That same attack was also used two weeks earlier against a large multinational defense contractor.

They also hoard vulnerabilities. During the 1999 conflict over the two-states theory conflict, in a heated exchange with a group of Taiwanese hackers, one Chinese group threatened to unleash multiple stockpiled worms at once. There was no reason to disbelieve this threat.

If anything, the fact that these groups aren’t being run by the Chinese government makes the problem worse. Without central political coordination, they’re likely to take more risks, do more stupid things and generally ignore the political fallout of their actions.

In this regard, they’re more like a non-state actor.

So while I’m perfectly happy that the U.S. government is using the threat of Chinese hacking as an impetus to get their own cybersecurity in order, and I hope they succeed, I also hope that the U.S. government recognizes that these groups are not acting under the direction of the Chinese military and doesn’t treat their actions as officially approved by the Chinese government.

This essay originally appeared on the Discovery Channel website.

EDITED TO ADD (7/18): A slightly longer version of this essay appeared in Information Security magazine as part of a point/counterpoint with Marcus Ranum. His half is here.

Posted on July 14, 2008 at 7:08 AM • View Comments

Ransomware

I’ve never figured out the fuss over ransomware:

Some day soon, you may go in and turn on your Windows PC and find your most valuable files locked up tighter than Fort Knox.

You’ll also see this message appear on your screen:

“Your files are encrypted with RSA-1024 algorithm. To recovery your files you need to buy our decryptor. To buy decrypting tool contact us at: ********@yahoo.com”

How is this any worse than the old hacker viruses that put a funny message on your screen and erased your hard drive?

Here’s how I see it, if someone actually manages to pull this up and put it into circulation, we’re looking at malware Armegeddon. Instead of losing ‘just’ your credit card numbers or having your PC turned into a spam factory, you could lose vital files forever.

Of course, you could keep current back-ups. I do, but I’ve been around this track way too many times to think that many companies, much less individual users, actually keep real back-ups. Oh, you may think you do, but when was the last time you checked to see if the data you saved could actually be restored?

The single most important thing any company or individual can do to improve security is have a good backup strategy. It’s been true for decades, and it’s still true today.

Posted on June 16, 2008 at 1:09 PM • View Comments

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Sidebar photo of Bruce Schneier by Joe MacInnis.