Krebs on Security

Who Wrote the Flashback OS X Worm?

April 3, 2013

A year ago today, Apple released a software update to halt the spread of the Flashback worm, a malware strain that infected more than 650,000 Mac OS X systems using a vulnerability in Apple’s version of Java. This somewhat dismal anniversary is probably as good a time as any to publish some clues I’ve gathered over the past year that point to the real-life identity of the Flashback worm’s creator.

Before I delve into the gritty details, a little background on this insidious contagion is in order. A keenly detailed research paper (PDF) published last year by Finnish security firm F-Secure puts the impact and threat from Flashback in perspective, noting that the malware boasted a series of “firsts” for its kind. For starters, Flashback was the first OS X malware to be “VMware aware” — or to know when it was being run in a virtual environment (a trick designed to frustrate security researchers). It also was the first to disable XProtect, OS X’s built-in malware protection program. These features, combined with its ability to spread through a then-unpatched vulnerability in Java made Flashback roughly as common for Macs as the Conficker Worm was for Windows PCs.

“This means Flashback is not only the most advanced, but also the most successful OS X malware we’ve ever seen,” wrote F-Secure’s Broderick Ian Aquilino.

The F-Secure writeup answers an important question not found in other analyses: Namely, what was the apparent intended purpose of Flashback? Put simply: to redirect Google results to third-party advertisers, all for the author’s profit. It’s name was derived from the fact that it spread using a social engineering trick of presenting the OS X user with a bogus Flash Player installation prompt. F-Secure notes that this same behavior — both the Flash social engineering trick and the redirection to fake Google sites that served search results for third-party advertisers that benefited the author — was also found in the QHost malware, suggesting that Flashback may have been the next evolution of the Mac QHost malware.

BLACK SEO

A year ago, I published a series that sought to identify the real-life hackers behind the top spam botnets. Using much the same methodology, I was able to identify and locate a young man in Russia who appears (and privately claims) to be the author of Flashback. As it happens, this individual hangs out on many of the same forums as the world’s top spammers (but more on that at another time).

Given Flashback’s focus on gaming Google’s ad networks, I suspected that the worm’s author probably was a key member of forums that focus on so-called “black hat SEO,” (search engine optimization), or learned in illicit ways to game search engines and manipulate ad revenues. Sure enough, this individual happens to be a very active and founding member of BlackSEO.com, a closely guarded Russian language forum dedicated to this topic.

Below is a screen shot taken from a private message between a “VIP” user named “Mavook” and a top forum member on BlackSEO.com. The conversation took place on July 14, 2012. A rough translation of their conversation is superimposed on the redacted screen grab, but basically it shows Mavook asking the senior member for help in gaining access to Darkode.com, a fairly exclusive English-language cybercrime forum (and one that I profiled in a story earlier this week).

BlackSEO.com member “Mavook” claims responsibility for creating Flashback to a senior forum member.

Mavook asks the other member to get him an invitation to Darkode, and Mavook is instructed to come up with a brief bio stating his accomplishments, and to select a nickname to use on the forum if he’s invited. Mavook replies that the Darkode nick should be not be easily tied back to his BlackSEO persona, and suggests the nickname “Macbook.” He also states that he is the “Creator of Flashback botnet for Macs,” and that he specializes in “finding exploits and creating bots.”

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Fool Me Once…

April 2, 2013

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When you’re lurking in the computer crime underground, it pays to watch your back and to keep your BS meter set to ‘maximum.’ But when you’ve gained access to an elite black market section of a closely guarded crime forum to which very few have access, it’s easy to let your guard down. That’s what I did earlier this year, and it caused me to chase a false story. This blog post aims to set the record straight on that front, and to offer a cautionary (and possibly entertaining) tale to other would-be cybersleuths.

On Jan. 16, 2013, I published a post titled, “New Java Exploit Fetches $5,000 Per Buyer.” The details in that story came from a sales thread posted to an exclusive subforum of Darkode.com, a secretive underground community that has long served as a bazaar for all manner of cybercriminal wares, including exploit kits, spam services, ransomware programs, and stealthy botnets. I’ve maintained a presence on this forum off and on (mostly on) for the past three years, in large part because Darkode has been a reliable place to find information about zero-days, or highly valuable threats that exploit previously unknown vulnerabilities in software — threats that are shared or used by attackers before the developer of the target software knows about the vulnerability.

I had previously broken several other stories about zero-day exploits for sale on Darkode that later showed up “in-the-wild” and confirmed by the affected vendors, and this sales thread was posted by one of the forum’s most trusted members. The sales thread also was created during a time in which Java’s maker Oracle Corp. was struggling with multiple zero-days in Java.

What I didn’t know at the time was that this particular sales thread was little more than a carefully laid trap by the Darkode administrators to discover which accounts I was using to lurk on their forum. Ironically, I recently learned of this snare after white/grey hat hackers compromised virtually all of the administrator accounts and private messages on Darkode.

“Looks like Krebs swallowed the bait, and i got an idea how to catch him now for the next thread,” wrote Darkode administrator “Mafi” in a Jan. 16 private message to a co-admin who uses the nickname “sp3cial1st”.

Following this post, the administrators compared notes as to which users had viewed the fake Java zero-day sales thread during the brief, two-day period it was live on a restricted portion of Darkode. “I have taken a careful examination of the logs related to the java 0day thread,” sp3cial1st wrote to a Darkode administrator who used the nick “187”.

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DHS Warns of ‘TDos’ Extortion Attacks on Public Emergency Networks

April 1, 2013

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As if emergency responders weren’t already overloaded: Increasingly, extortionists are launching debilitating attacks designed to overwhelm the telephone networks of emergency communications centers and personnel, according to a confidential alert jointly issued by the Department of Homeland Security and the FBI.

“TDos” warning

The alert, a copy of which was obtained by KrebsOnSecurity, warns public safety answering points (PSAPs) and emergency communications centers and personnel about a recent spike in so-called “telephony denial-of-service” (TDoS) attacks:

“Information received from multiple jurisdictions indicates the possibility of attacks targeting the telephone systems of public sector entities. Dozens of such attacks have targeted the administrative PSAP lines (not the 911 emergency line). The perpetrators of the attack have launched high volume of calls against the target network, tying up the system from receiving legitimate calls. This type of attack is referred to as a TDoS or Telephony Denial of Service attack. These attacks are ongoing. Many similar attacks have occurred targeting various businesses and public entities, including the financial sector and other public emergency operations interests, including air ambulance, ambulance and hospital communications.”

According to the alert, these recent TDoS attacks are part of a bizarre extortion scheme that apparently starts with a phone call to an organization from an individual claiming to represent a collections company for payday loans. The caller usually has a strong accent of some sort and asks to speak with a current or former employee concerning an outstanding debt. Failing to get payment from an individual or organization, the perpetrator launches a TDoS attack. The organization will be inundated with a continuous stream of calls for an unspecified, but lengthy period of time.

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Cash Claws, Fake Fascias & Tampered Tickets

March 28, 2013

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Credit and debit card skimmers aren’t just for ATMs anymore. According to European anti-fraud experts, innovative skimming devices are turning up on everything from train ticket kiosks to parking meters and a host of other unattended payment terminals.

Recently, at least five countries reported skimming attacks against railway or transport ticket machines, according to the European ATM Security Team (EAST), a not-for-profit organization that collects data on skimming attacks. Two countries reported skimming attacks at parking machines, and three countries had skimming incidents involving point-of-sale terminals. EAST notes that Bluetooth devices increasingly are being used to transit stolen card and PIN data wirelessly.

Skimming devices found at train ticket kiosks in Europe. Source: EAST

The organization also is tracking a skimming trend reported by three countries (mainly in Latin America) in which thieves are fabricating fake ATM fascias and placing them over genuine ATMs, like the one pictured below. After entering their PIN, cardholders see an ‘out-of-order’ message. EAST said the fake fascias include working screens so that this type of message can be displayed. The card details are compromised by a skimming device hidden inside the fake fascia, and the PINs are captured via the built-in keypad, which overlays the real keypad underneath.

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Missouri Court Rules Against $440,000 Cyberheist Victim

March 26, 2013

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A Missouri court last week handed a legal defeat to a local escrow firm that sued its financial institution to recover $440,000 stolen in a 2009 cyberheist. The court ruled that the company assumed greater responsibility for the incident because it declined to use a basic security precaution recommended by the bank: requiring two employees to sign off on all transfers.

Springfield, Mo. based Choice Escrow and Land Title LLC sued Tupelo, Miss. based BancorpSouth Inc., after hackers who had stolen the firm’s online banking ID and password used the information to make a single unauthorized wire transfer of $440,000 to a corporate bank account in Cyprus.

Choice Escrow alleged that BancorpSouth’s security procedures were not commercially reasonable. Choice pointed out that the bank’s most secure option for Internet-based authentication relied principally on so-called “dual controls,” or requiring business customers to have one user ID and password to approve a wire transfer and another user ID and password to release the same wire transfer.

Choice Escrow’s lawyers argued that because BancorpSouth allowed wire or funds transfers using two options which were both password-based, its commercial online banking security procedures fell short of 2005 guidance from the Federal Financial Institutions Examination Council (FFIEC), which warned that single-factor authentication as the only control mechanism is inadequate for high-risk transactions involving the movement of funds to other parties.

But in a decision handed down on March 18, 2013, a judge with the U.S. District Court for the Western District of Missouri focused on the fact that Choice Escrow was offered and explicitly declined in writing the use of dual controls, thereby allowing the thieves to move money directly out their account using nothing more than a stolen username and password. The court noted that Choice also declined to set a limit on the amount or number of wire transfers allowed each day (another precaution urged by the bank), and that the transfer amount initiated by the thieves was not unusual for Choice, a company that routinely moved large sums of money.

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Privacy 101: Skype Leaks Your Location

March 21, 2013

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The events of the past week reminded me of a privacy topic I’ve been meaning to revisit: That voice-over-IP telephony service Skype constantly exposes your Internet address to the entire world, and that there are now numerous free and commercial tools that can be used to link Skype user account names to numeric Internet addresses.

A Skype resolver service in action.

The fact that Skype betrays its users’ online location information is hardly news. For example, The Wall Street Journal and other news outlets warned last year about research showing that it was possible to coax Skype into revealing the IP addresses of individual Skype users. But I believe most Skype users still have no clue about this basic privacy weakness.

What’s changed is that over the past year, a number of services have emerged to help snoops and ne’er-do-wells exploit this vulnerability to track and harass others online. For example, an online search for “skype resolver” returns dozens of results that point to services (of variable reliability) that allow users to look up the Internet address of any Skype user, just by supplying the target’s Skype account name.

In the above screen shot, we can see one such service being used to display the IP address most recently used by the Skype account “mailen_support” (this particular account belongs to the tech support contact for Mailien, a Russian pharmacy spam affiliate program by the same name).

A Skype IP resolver service in action.

Typically, these Skype resolvers are offered in tandem with “booter” or “stresser” services, online attack tools-for-hire than can be rented to launch denial-of-service attacks (one of these services was used in an attack on this Web site, and on that of Ars Technica last week). The idea being that if you want to knock someone offline but you don’t know their Internet address, you can simply search on Skype to see if they have an account, and then use the resolvers to locate their IP. The resolvers work regardless of any privacy settings the target user may have selected within the Skype program’s configuration panel.

Many of these resolver services offer “blacklisting,” which for a fee will allow users to prevent other users from looking up the IP address attached to a specific Skype account, said Brandon Levene, an independent security researcher.

“It’s basically a protection scheme,” Levene said.

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The Obscurest Epoch is Today

March 18, 2013

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“History is much decried; it is a tissue of errors, we are told, no doubt correctly; and rival historians expose each other’s blunders with gratification. Yet the worst historian has a clearer view of the period he studies than the best of us can hope to form of that in which we live. The obscurest epoch is to-day; and that for a thousand reasons of incohate tendency, conflicting report, and sheer mass and multiplicity of experience; but chiefly, perhaps, by reason of an insidious shifting of landmarks.” – Robert Louis Stevenson

To say that there is a law enforcement manhunt on for the individuals responsible for posting credit report information on public figures and celebrities at the rogue site exposed.su would be a major understatement. I like to think that when that investigation is completed, some of the information I’ve helped to uncover about those affiliated with the site will come to light. For now, however, I’m content to retrace some of my footwork this past weekend that went into tracking individuals who may have been responsible for attacking my site and SWATing my home last Thursday.

I state upfront that the information in this piece is certainly not the whole story (most news reporting is, at best, a snapshot in time, a first rough draft of history). While the clues I’ve uncovered thus far point to the role of a single individual, this person is likely part of a larger group involved in hacking and SWATing activity.

In my story last week, I posted a copy of the internal database for booter.tw, one of several fee-for-service “booter” sites. Booter sites are perhaps most popular among online gaming enthusiasts, who like to use them to knock opponents offline; but they are frequently also used to launch debilitating attacks on Web sites. That leaked booter.tw database shows that the denial-of-service attack that hit my site last week was paid for by a booter.tw user with the account name “countonme,” and using the address “countonme@gmail.com.”

Since the attack, I reached out to the proprietor of booter.tw, a hacker who uses the nickname “Askaa.” He informed me that the individual who launched the attack on my site was a hacker who used the screen name Phobia. “Phobia hacked into the countonme account to make it look like the according user attacked you,” Askaa said in a brief interview over Skype instant message. Askaa declined to say why he was so confident of this information.

RealTeamHype’s Youtube page before the videos were deleted on Sunday.

Separately, over the weekend I received an email from a person who claimed to have direct knowledge of the attacks (perhaps because he, too, was involved). This individual said those who attacked my site were a group of young online video game enthusiasts who were upset that earlier in the week I’d written about ssndob.ru, a site that sells access to peoples’ credit files, Social Security numbers and other sensitive information.

According to this source, the hackers in this case belong to a four-man Xbox live gamer team that calls itself “Team Hype,” which until this past weekend had posted a number of videos to their own youtube.com channel, RealTeamHype (more on what happened to these videos in a moment).

According to the anonymous source, Team Hype consists of hackers who use the nicknames “Trojan,” “Shadow,” Convict,” and “Phobia.” The source said the group used SSNs from ssndob.ru to hijack “gamertags,” online personas tied to Xbox Live game accounts. In this case, specifically from Microsoft employees who work on the Xbox Live gaming platform. Some of the group members then sell those accounts to other Xbox Live players.

“They hack/social engineer Gamertags off Microsoft employees by using SSNs,” the source wrote. “I didn’t DDoS your site and I didn’t SWAT you, Phobia has been telling everyone he did. The method he released he said he gets SSNs, then calls phone companies and redirects the number and than gets xbox phone support to call number and confirm. I heard he got pissed that you released the site he uses. Also Trojan told a buddie of mines ‘fear'(on AIM) something about a dead body in your closet about your swat.”

Snippet from @PhobiaTheGod’s now-closed Twitter account

The source said Phobia used the Twitter account @PhobiaTheGod (now closed, but partially available here and at this cache), and that Phobia’s personal information — including real name, address and phone number — had been “doxed” or released onto Pastebin-like sites some time ago. It didn’t take long to locate this profile at skidpaste.org (“skid” is a diminutive reference to the term “script kiddies,” referring to relatively unskilled young hackers who conduct most of their exploits using automated tools without understanding how those tools actually do the dirty work).

Having watched most of the videos at RealTeamHype’s youtube channel, it appeared that my source was telling the truth about the hijacked accounts: In fact, the videos at that channel documented such hijackings in progress using desktop screen-grabbing software. The videos even showed conversations with other team members in instant message windows in the background.

But I was reluctant to put much stock in the information until the source sent me a piece of information that only the attackers and my ISP would have known. On Friday, I received a call from Cox Communications, my Internet service provider. They wanted to know why I had paid $3,000 toward my account using several different credit card numbers. I assured them that I hadn’t made that payment. Then I heard from a member of Cox’s security team, who asked if I’d reset my password and if I’d indeed asked to cancel my Internet service. He was unsurprised to learn that I hadn’t. Apparently, hackers reset the password to my Cox email account by working out the answer to my secret question (this account is separate from my Cox user account, was set up over 10 years ago, and has never been used for anything remotely interesting or sensitive).

The source told me via email: “Hey brian, i just spoke to fear he told me phobia and his buddies were telling him that they hacked your cox email and paid your cox bill with hacked credit card, im not sure if this is true but im letting you know.”

I decided to give a call to the phone number included in the doxed records for Phobia, which rang at a home in Milford, Ct. A 20-year-old named Ryan Stevenson picked up the phone. After introducing myself, I asked Ryan if he knew anything about booter.tw, and he said he didn’t bother with booter sites because they were lame.

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The World Has No Room For Cowards

March 15, 2013

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It’s not often that one has the opportunity to be the target of a cyber and kinetic attack at the same time. But that is exactly what’s happened to me and my Web site over the past 24 hours. On Thursday afternoon, my site was the target of a fairly massive denial of service attack. That attack was punctuated by a visit from a heavily armed local police unit that was tricked into responding to a 911 call spoofed to look like it came from my home.

Well, as one gamer enthusiast who follows me on Twitter remarked, I guess I’ve now “unlocked that level.”

Things began to get interesting early Thursday afternoon, when a technician from Prolexic, a company which protects Web sites (including KrebsOnSecurity.com) from denial-of-service attacks, forwarded a strange letter they’d received earlier in the day that appeared to have been sent from the FBI. The letter, a copy of which is reprinted in its entirety here, falsely stated that my site was hosting illegal content, profiting from cybercriminal activity, and that it should be shut down. Prolexic considered it a hoax, but forwarded it anyway. I similarly had no doubt it was a fake, and a short phone call to the FBI confirmed that fact.

Around the same time, my site came under a series of denial-of-service attacks, briefly knocking it offline. While Prolexic technicians worked to filter the attack traffic, I got busy tidying up the house (since we were expecting company for dinner). I heard the phone ring up in the office while I was downstairs vacuuming the living room and made a mental note to check my voicemail later. Vacuuming the rug near the front door, I noticed that some clear plastic tape I’d used to secure an extension cord for some outdoor lights was still straddling the threshold of the front door.

Fairfax County Police outside my home on 3/14/13

When I opened the door to peel the rest of the tape off, I heard someone yell, “Don’t move! Put your hands in the air.” Glancing up from my squat, I saw a Fairfax County Police officer leaning over the trunk of a squad car, both arms extended and pointing a handgun at me. As I very slowly turned my head to the left, I observed about a half-dozen other squad cars, lights flashing, and more officers pointing firearms in my direction, including a shotgun and a semi-automatic rifle. I was instructed to face the house, back down my front steps and walk backwards into the adjoining parking area, after which point I was handcuffed and walked up to the top of the street.

I informed the responding officers that this was a hoax, and that I’d even warned them in advance of this possibility. In August 2012, I filed a report with Fairfax County Police after receiving non-specific threats. The threats came directly after I wrote about a service called absoboot.com, which is a service that can be hired to knock Web sites offline.

One of the reasons that I opted to file the report was because I knew some of the young hackers who frequented the forum on which this service was advertised had discussed SWATting someone as a way of exacting revenge or merely having fun at the target’s expense. To my surprise, the officer who took my report said he had never heard of the phenomenon, but promised to read up on it.

One of the officers asked if it was okay to enter my house, and I said sure. Then an officer who was dressed more like a supervisor approached me and asked if I was the guy who had filed a police report about this eventuality about six months earlier. When I responded in the affirmative, he spoke into his handheld radio, and the police began stowing their rifles and the cuffs were removed from my wrists. He explained that they’d tried to call me on the phone number that had called them (my mobile), but that there was no answer. He apologized for the inconvenience, and said they were only doing their jobs. I told him no hard feelings. He told me that the problem of SWATting started on the West Coast and has been slowly making its way east.

The cop that took the report from me after the incident said someone had called 911 using a Caller ID number that matched my mobile phone number; the caller claimed to be me, reporting that Russians had broken into the home and shot my wife. Obviously, this was not the case, and nobody was harmed during the SWATing.

Update, Apr. 29, 2013: As I noted halfway through this follow-up post, the police officer was misinformed: The 911 call was actually made via instant message chats using a relay service designed for hearing impaired and deaf callers, *not* via a spoofed mobile phone call.

Original story:

It’s difficult to believe the phony FBI letter that Prolexic received, the denial-of-service attack, and the SWATting were somehow the work of different individuals upset over something I’ve written. The letter to Prolexic made no fewer than five references to a story I published earlier this week about sssdob.ru, a site advertised in the cybercrime underground that sells access to Social Security numbers and credit reports. That story was prompted by news media attention to exposed.su, a site that has been posting what appear to be Social Security numbers, previous addresses and other information on highly public figures, including First Lady Michelle Obama and the director of the FBI.

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Credit Reports Sold for Cheap in the Underweb

March 13, 2013

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Following the online publication of Social Security numbers and other sensitive data on high-profile Americans, the three major credit reporting bureaus say they’ve uncovered cases where hackers gained access to users’ information, Bloomberg reports. The disclosure, while probably discomforting for many, offers but a glimpse of the sensitive data available to denizens of the cybercrime underworld, which hosts several storefronts that sell cheap, illegal access to consumer credit reports.

Redacted screen shot of leaked records.

The acknowledgement by Experian, Equifax and Trans Union comes hours after hackers posted online Social Security numbers and other sensitive data on FBI Director Robert Muller, First Lady Michelle Obama, Paris Hilton and others.

Sadly, Social Security numbers and even credit reports are not difficult to find using inexpensive services advertised openly in several cybercrime forums. In most cases, these services are open to all comers; the only limitation is knowing the site’s current Web address (such sites tend to move frequently) and being able to fund an account with a virtual currency, such as WebMoney or Liberty Reserve.

Case in point: ssndob.ru, a Web site that sells access to consumer credit reports for $15 per report. The site also sells access to drivers license records ($4) and background reports ($12), as well as straight SSN and date of birth lookups. Random “fulls” records — which include first, middle and last names, plus the target’s address, phone number, SSN and DOB — sell for 50 cents each. Fulls located by DOB cost $1, and $1.50 if searched by ZIP Code.

Credit report lookup page at ssndob.ru

It’s not clear from where this service gets its credit reports and other data, but it appears that at least some of the lookups are done manually by the proprietors. Pending new records requests are tracked with varying messages, such as “in queue,” and “in progress,” and often take more than 15 minutes to process.

A source who agreed to have their information looked up at this service provided his Social Security number, date of birth and address. Within 15 minutes, the site returned a full credit report produced by TransUnion; the report, saved as an HMTL file, was archived in a password protected zip file and uploaded to sendspace.com, with a link to the file and a password to unlock the archive.

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Critical Updates for Windows, Adobe Flash, Air

March 12, 2013

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Microsoft and Adobe each released patches today to plug critical security holes in their products. Microsoft issued seven update bundles to address at least 19 20 vulnerabilities in Windows and related software. Adobe released the fourth security update in nearly as many weeks for its Flash Player software, as well as a fix for Adobe AIR.

Microsoft today began pushing out seven security patches, four of them rated “critical,” meaning the flaws they fix could be used by malware or bad guys to break into unpatched systems with little or no help from users. The critical patches address bugs in Windows, Internet Explorer, Microsoft Silverlight, Microsoft Office and Microsoft SharePoint. Updates are available for Windows XP, Vista, Windows 7, Windows 8, Windows Server 2003, 2008 and 2012.

More information on the Microsoft patches is available at the Microsoft security response center blog, which also discusses some changes to the way security updates are applied to apps available through the Windows Store.

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