Krebs on Security

Backstage with the Gameover Botnet Hijackers

June 9, 2014

When you’re planning to rob the Russian cyber mob, you’d better make sure that you have the element of surprise, that you can make a clean getaway, and that you understand how your target is going to respond. Today’s column features an interview with two security experts who helped plan and execute last week’s global, collaborative effort to hijack the Gameover Zeus botnet, an extremely resilient and sophisticated crime machine that helped an elite group of thieves steal more than $100 million from banks, businesses and consumers worldwide.

Gameover infections on June 4, 2014. Source: Shadowserver.org

Neither expert I spoke with wished to be identified for this story, citing a lack of permission from their employers and a desire to remain off the radar of the crooks inconvenienced by the action. For obvious reasons, they were also reluctant to share details about the exact weaknesses that were used to hijack the botnet, focusing instead on the planning and and preparation that went into this effort.

GAMEOVER ZEUS PRIMER

A quick review of how Gameover works should help readers get more out of the interview. In traditional botnets, infected PCs report home to and are controlled by a central server. But this architecture leaves such botnets vulnerable to disruption or takeover if authorities or security experts can gain access to the control server.

Gameover, on the other hand, is a peer-to-peer (P2P) botnet designed as a collection of small networks that are distinct but linked up in a decentralized fashion. The individual Gameover-infected PCs are known as “peers.” Above the peers are a select number of slightly more powerful and important infected systems that are assigned roles as “proxy nodes,” meaning they were selected from the peers to serve as relay points for commands coming from the Gameover botnet operators and as conduits for encrypted data stolen from the infected systems.

The basic network structure of the Gameover botnet. Source: FBI

The Gameover botnet code also includes a failsafe mechanism that can be invoked if the botnet’s P2P communications system fails, whether the failure is the result of a faulty malware update or because of a takedown effort by researchers/law enforcement. That failsafe is a domain generation algorithm (DGA) component that generates a list of 1,000 domain names each week (gibberish domains that are essentially long jumbles of letters) combined with one of six top-level domains; .com, .net, .org, .biz, .info and .ru. In the event the infected Gameover systems can’t get new instructions from their peers, the code instructs the botted systems to seek out domains from the latest list of 1,000 domains generated by the DGA until it finds a site with new instructions.

HUNDREDS OF ‘WEB INJECTS’

The Gameover malware was designed specifically to defeat two-factor authentication used by many banks. It did so using a huge collection of custom-made scripts known as “Web injects” that can inject custom content into a Web browser when the victim browses to certain sites — such as a specific bank’s login page. Web injects also are used to prompt the victim to enter additional personal information when they log in to a trusted site. An example of this type of Web inject can be seen in the video below, which shows an inject designed for Citibank customers. Continue reading →

They Hack Because They Can

June 5, 2014

87 Comments

The Internet of Things is coming….to a highway sign near you? In the latest reminder that much of our nation’s “critical infrastructure” is held together with the Internet equivalent of spit and glue, authorities in several U.S. states are reporting that a hacker has once again broken into and defaced electronic road signs over highways in several U.S. states.

Image: WNCN.

Earlier this week, news media in North Carolina reported that at least three highway signs there had apparently been compromised and re-worded to read “Hack by Sun Hacker.” Similar incidents were reported between May 27 and June 2, 2014 in two other states, which spotted variations on that message left by the perpetrator, (including an invitation to chat with him on Twitter).

The attack was reminiscent of a series of incidents beginning two years ago in which various electronic message signs were changed to read “Warning, Zombies Ahead”.

While at least those attacks were chuckle-worthy, messing with traffic signs is no laughing matter: As a report by the Multi-State Information Sharing and Analysis Center (MS-ISAC) points out, changes to road signs create a public safety issue because instead of directing drivers through road hazards, they often result in drivers slowing or stopping to view the signs or take pictures.

That same MS-ISAC notice, obtained by KrebsOnSecurity and published here (PDF), points out that these incidents appear to be encouraged by sloppy security on the part of those responsible for maintaining these signs.

“Investigators in one state believe the compromise may be in part due to the use of weak Simple Network Management Protocol (SNMP) community strings. Investigators in another state believe the malicious actor used Telnet port 23 and a simple password cracker to gain remote access. In one state the malicious actor changed the modem passwords, forcing technicians to restore to factory default settings to regain access.”

Continue reading →

Peek Inside a Professional Carding Shop

June 4, 2014

88 Comments

Over the past year, I’ve spent a great deal of time trolling a variety of underground stores that sell “dumps” — street slang for stolen credit card data that buyers can use to counterfeit new cards and go shopping in big-box stores for high-dollar merchandise that can be resold quickly for cash. By way of explaining this bizarro world, this post takes the reader on a tour of a rather exclusive and professional dumps shop that caters to professional thieves, high-volume buyers and organized crime gangs.

The subject of this post is “McDumpals,” a leading dumps shop that first went online in late April 2013. Featuring the familiar golden arches and the bastardized logo, “i’m swipin’ it,” the site’s mascot is a gangstered-up Ronald McDonald pointing a handgun at the viewer.

Nevermind that this shop is violating a ridiculous number of McDonald’s trademarks in one fell swoop: It’s currently selling cards stolen from data breaches at main street stores in nearly every U.S. state.

Like many other dumps shops, McDumpals recently began requiring potential new customers to pay a deposit (~$100) via Bitcoin before being allowed to view the goods for sale. Also typical of most card shops, this store’s home page features the latest news about new batches of stolen cards that have just been added, as well as price reductions on older batches of cards that are less reliable as instruments of fraud.

I’ve put together a slideshow (below) that steps through many of the updates that have been added to this shop since its inception. One big takeaway from this slideshow is that many shops are now categorizing their goods for sale by the state or region of the victim company.

This was a major innovation that we saw prominently on display in the card shop that was principally responsible for selling cards stolen in the Target and Sally Beauty retail breaches: In those cases, buyers were offered the ability to search for cards by the city, state and ZIP of the Target and Sally Beauty stores from which those cards were stolen. Experienced carders (as buyers are called) know that banks will often flag transactions as suspicious if they take place outside of the legitimate cardholder’s regular geographic purchasing patterns, and so carders tend to favor cards stolen from consumers who live nearby.

The slideshow may make more sense if readers familiarize themselves with a few terms and phrases that show up in the text:

Continue reading →

Ne’er-Do-Well News, Volume I

June 3, 2014

35 Comments

It’s been a while since a new category debuted on this blog, and it occurred to me that I didn’t have a catch-all designation for random ne’er-do-well news. Alas, the inaugural entry for Ne’er-Do-Well News looks at three recent unrelated developments: The availability of remote access iPhone apps written by a programmer perhaps best known for developing crimeware; the return to prison of a young hacker who earned notoriety after simultaneously hacking Paris Hilton’s cell phone and data broker LexisNexis; and the release of Pavel Vrublevsky from a Russian prison more than a year before his sentence was to expire.

ZeusTerm and Zeus Terminal are iPhone/iPad apps designed by the same guy who brought us the Styx-Crypt exploit kit.

A year ago, this blog featured a series of articles that sought to track down the developers of the Styx-Crypt exploit kit, a crimeware package being sold to help bad guys booby-trap compromised Web sites with malware. Earlier this week, I learned that a leading developer of Styx-Crypt — a Ukrainian man named Max Gavryuk — also is selling his own line of remote administration tools curiously called “Zeus Terminal,” available via the Apple iTunes store.

News of the app family came via a Twitter follower who asked to remain anonymous, but who said two of the apps by this author were recently pulled from Apple’s iTunes store, including Zeus Terminal and Zeus Terminal Lite. It’s unclear why the apps were yanked or by whom, but the developer appears to have two other remote access apps for sale on iTunes, including ZeusTerm and ZeusTerm HD.

Incidentally, the support page listed for these apps — zeus-terminal[dot]com — no longer appears to be active (if, indeed it ever was), but the developer lists as his other home page reality7solutions[dot]com, which as this blog has reported was intricately tied to the Styx-Crypt development team.

This wouldn’t be the first time a crimeware author segued into building apps for the iPhone and iPad: In January 2012, as part of my Pharma Wars series, I wrote about clues that strongly suggested the Srizbi/Reactor spam botnet was developed and sold by a guy who left the spam business to build OOO Gameprom, a company that has developed dozens of games available in the iTunes store.

Continue reading →

‘Operation Tovar’ Targets ‘Gameover’ ZeuS Botnet, CryptoLocker Scourge

June 2, 2014

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The U.S. Justice Department is expected to announce today an international law enforcement operation to seize control over the Gameover ZeuS botnet, a sprawling network of hacked Microsoft Windows computers that currently infects an estimated 500,000 to 1 million compromised systems globally. Experts say PCs infected with Gameover are being harvested for sensitive financial and personal data, and rented out to an elite cadre of hackers for use in online extortion attacks, spam and other illicit moneymaking schemes.

This graphic, from 2012, shows the decentralized nature of P2P network connectivity of 23,196 PCs infected with Gameover. Image: Dell SecureWorks

The sneak attack on Gameover, dubbed “Operation Tovar,” began late last week and is a collaborative effort by investigators at the FBI, Europol, and the UK’s National Crime Agency; security firms CrowdStrike, Dell SecureWorks, Symantec, Trend Micro and McAfee; and academic researchers at VU University Amsterdam and Saarland University in Germany. News of the action first came to light in a blog post published briefly on Friday by McAfee, but that post was removed a few hours after it went online.

Gameover is based on code from the ZeuS Trojan, an infamous family of malware that has been used in countless online banking heists. Unlike ZeuS — which was sold as a botnet creation kit to anyone who had a few thousand dollars in virtual currency to spend — Gameover ZeuS has since October 2011 been controlled and maintained by a core group of hackers from Russia and Ukraine.

Those individuals are believed to have used the botnet in high-dollar corporate account takeovers that frequently were punctuated by massive distributed-denial-of-service (DDoS) attacks intended to distract victims from immediately noticing the thefts. According to the Justice Department, Gameover has been implicated in the theft of more than $100 million in account takeovers.

The curators of Gameover also have reportedly loaned out sections of their botnet to vetted third-parties who have used them for a variety of purposes. One of the most popular uses of Gameover has been as a platform for seeding infected systems with CryptoLocker, a nasty strain of malware that locks your most precious files with strong encryption until you pay a ransom demand.

According to a 2012 research paper published by Dell SecureWorks, the Gameover Trojan is principally spread via Cutwail, one of the world’s largest and most notorious spam botnets (for more on Cutwail and its origins and authors, see this post). These junk emails typically spoof trusted brands, including shipping and phone companies, online retailers, social networking sites and financial institutions. The email lures bearing Gameover often come in the form of an invoice, an order confirmation, or a warning about an unpaid bill (usually with a large balance due to increase the likelihood that a victim will click the link). The links in the email have been replaced with those of compromised sites that will silently probe the visitor’s browser for outdated plugins that can be leveraged to install malware.

It will be interesting to hear how the authorities and security researchers involved in this effort managed to gain control over the Gameover botnet, which uses an advanced peer-to-peer (P2P) mechanism to control and update the bot-infected systems. Continue reading →

Thieves Planted Malware to Hack ATMs

May 30, 2014

78 Comments

A recent ATM skimming attack in which thieves used a specialized device to physically insert malicious software into a cash machine may be a harbinger of more sophisticated scams to come.

Two men arrested in Macau for allegedly planting malware on local ATMs (shown with equipment reportedly seized from their hotel room).

Authorities in Macau — a Chinese territory approximately 40 miles west of Hong Kong — this week announced the arrest of two Ukrainian men accused of participating in a skimming ring that stole approximately $100,000 from at least seven ATMs. Local police said the men used a device that was connected to a small laptop, and inserted the device into the card acceptance slot on the ATMs.

Armed with this toolset, the authorities said, the men were able to install malware capable of siphoning the customer’s card data and PINs. The device appears to be a rigid green circuit board that is approximately four or five times the length of an ATM card.

According to local press reports (and supplemented by an interview with an employee at one of the local banks who asked not to be named), the insertion of the circuit board caused the software running on the ATMs to crash, temporarily leaving the cash machine with a black, empty screen. The thieves would then remove the device. Soon after, the machine would restart, and begin recording the card and PINs entered by customers who used the compromised machines.

The Macau government alleges that the accused would return a few days after infecting the ATMs to collect the stolen card numbers and PINs. To do this, the thieves would reinsert the specialized chip card to retrieve the purloined data, and then a separate chip card to destroy evidence of the malware. Here’s a look at the devices that Macau authorities say the accused used to insert the malware into ATMs (I’m working on getting clearer photos of this hardware):

Five of the devices Macau police say the thieves used to insert the malware and retrieve stolen data.

Continue reading →

True Goodbye: ‘Using TrueCrypt Is Not Secure’

May 29, 2014

363 Comments

The anonymous developers responsible for building and maintaining the free whole-disk encryption suite TrueCrypt apparently threw in the towel this week, shuttering the TrueCrypt site and warning users that the product is no longer secure now that Microsoft has ended support for Windows XP.

Sometime in the last 24 hours, truecrypt.org began forwarding visitors to the program’s home page on sourceforge.net, a Web-based source code repository. That page includes instructions for helping Windows users transition drives protected by TrueCrypt over to BitLocker, the proprietary disk encryption program that ships with every Windows version (Ultimate/Enterprise ~~or Pro~~) since Vista. The page also includes this ominous warning:

“WARNING: Using TrueCrypt is not secure as it may contain unfixed security issues”

“This page exists only to help migrate existing data encrypted by TrueCrypt.”

“The development of TrueCrypt was ended in 5/2014 after Microsoft terminated support of Windows XP. Windows 8/7/Vista and later offer integrated support for encrypted disks and virtual disk images. Such integrated support is also available on other platforms (click here for more information). You should migrate any data encrypted by TrueCrypt to encrypted disks or virtual disk images supported on your platform.”

Doubters soon questioned whether the redirect was a hoax or the result of the TrueCrypt site being hacked. But a cursory review of the site’s historic hosting, WHOIS and DNS records shows no substantive changes recently.

What’s more, the last version of TrueCrypt uploaded to the site on May 27 (still available at this link) shows that the key used to sign the executable installer file is the same one that was used to sign the program back in January 2014 (hat tip to @runasand and @pyllyukko). Taken together, these two facts suggest that the message is legitimate, and that TrueCrypt is officially being retired.

That was the same conclusion reached by Matthew Green, a cryptographer and research professor at the Johns Hopkins University Information Security Institute and a longtime skeptic of TrueCrypt — which has been developed for the past 10 years by a team of anonymous coders who appear to have worked diligently to keep their identities hidden.

“I think the TrueCrypt team did this,” Green said in a phone interview. “They decided to quit and this is their signature way of doing it.”

Green last year helped spearhead dual crowdfunding efforts to raise money for a full-scale, professional security audit of the software. That effort ended up pulling in more than $70,000 (after counting the numerous Bitcoin donations) — far exceeding the campaign’s goal and demonstrating strong interest and support from the user community. Earlier this year, security firm iSEC Partners completed the first component of the code review: an analysis of TrueCrypt’s bootloader (PDF). Continue reading →

Backdoor in Call Monitoring, Surveillance Gear

May 28, 2014

20 Comments

If your company’s core business is making software designed to help first responders and police record and intercept phone calls, it’s probably a good idea to ensure the product isn’t so full of security holes that it allows trivial access by unauthorized users. Unfortunately, even companies working in this sensitive space fall victim to the classic blunder that eventually turns most software into Swiss Cheese: Trying to bolt on security only after the product has shipped.

Few companies excel at showcasing such failures as SEC Consult Vulnerability Lab, a software testing firm based in Vienna, Austria. In a post last year called Security Vendors: Do No Harm, Heal Thyself, I wrote about Symantec quietly fixing serious vulnerabilities that SEC Consult found in its Symantec Web Gateway, a popular line of security appliances designed to help “protect organizations against multiple types of Web-borne malware.” Prior to that, this blog showcased the company’s research on backdoors it discovered in security hardware and software sold by Barracuda Networks.

Today’s post looks at backdoors and other serious vulnerabilities SEC Consult found in products made by NICE Systems, an Israeli software firm that sells a variety of call recording solutions for law enforcement, public safety organizations and small businesses. According to SEC Consult, NICE’s Recording eXpress — a call recording suite designed for small and medium-sized public safety organizations (PDF) — contains an undocumented backdoor account that provides administrator-level access to the product.

“Attackers are able to completely compromise the voice recording / surveillance solution as they can gain access to the system and database level and listen to recorded calls without prior authentication,” wrote Johannes Greil and Stefan Viehböck of SEC Consult. “Furthermore, attackers would be able to use the voice recording server as a jumphost for further attacks of the internal voice VLAN, depending on the network setup.” Continue reading →

Complexity as the Enemy of Security

May 27, 2014

66 Comments

Late last month, hackers allied with the Syrian Electronic Army (SEA) compromised the Web site for the RSA Conference, the world’s largest computer security gathering. The attack, while unremarkable in many ways, illustrates the continued success of phishing attacks that spoof top executives within targeted organizations. It’s also a textbook example of how third-party content providers can be leveraged to break into high-profile Web sites.

A message left for Ira Winkler by the SEA.

The hack of rsaconference.com happened just hours after conference organizers posted several presentation videos from the February RSA Conference sessions, including one by noted security expert Ira Winkler that belittled the SEA’s hacking skills and labeled them “the cockroaches of the Internet.”

Shortly after that video went live, people browsing rsaconference.com with JavaScript enabled in their browser would have seen the homepage for the conference site replaced with a message from the SEA to Winkler stating, “If there is a cockroach in the internet it would definitely be you”.

The attackers were able to serve the message by exploiting a trust relationship that the RSA conference site had with a third-party hosting provider. The conference site uses a Web analytics package called “Lucky Orange,” which keeps track of how visitors use and browse the site. That package contained a Javascript function that called home to a stats page on a server hosted by codero.com, a hosting firm based in Austin, Texas.

According to Codero CEO Emil Sayegh, the attackers spoofed several messages from Codero executives and sent them to company employees. The messages led to a link that prompted the recipients to enter their account credentials, and someone within the organization who had the ability to change the domain name system (DNS) records for Codero fell for the ruse.

Sayegh said the attackers followed the script laid out in Winkler’s talk, almost to the letter.

“Go look at minute 16 from his talk,” Sayegh said. “It’s phenomenal. That’s exactly what they did.”

Continue reading →

Expert: Fake eBay Customer List is Bitcoin Bait

May 22, 2014

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In the wake of eBay’s disclosure that a breach may have exposed the personal data on tens of millions of users, several readers have written in to point out an advertisement that is offering to sell the full leaked user database for 1.4 bitcoins (roughly USD $772 at today’s exchange rates). The ad has even prompted some media outlets to pile on that the stolen eBay data is now for sale. But a cursory examination of the information suggests that it is almost certainly little more than a bid to separate the unwary from their funds.

The advertisement, posted on Pastebin here, promises a “full ebay user database dump with 145, 312, 663 unique records”, for sale to anyone who sends 1.453 bitcoins to a specific bitcoin wallet. The ad includes a link to a supposed “sample dump” of some 12,663 users from the Asia-Pacific region.

There is a surprisingly simple method for determining the validity of these types of offers. Most Web-based businesses allow one user or customer account per email address, and eBay is no exception here. I took a random sampling of five email addresses from the 12,663 users in that file, and tried registering new accounts with them. The outcome? Success on all five.

For a sanity check on my results, I reached out to Allison Nixon, a threat researcher with Deloitte & Touche LLP (and one of the best sources I’ve met for vetting and debunking these supposed “leaks”). Nixon did the same, and came away with identical results.

“A lot of this is inference — finding out whether an account exists,” Nixon said. “A lot of the time if they generate fake leaks, they’re not doing it based on data from real accounts, because if they did then they might as well hack the real web site.” Continue reading →

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