Krebs on Security

Breach Blind Spot Puts Retailers on Defensive

February 28, 2014

In response to rumors in the financial industry that Sears may be the latest retailer hit by hackers, the company said today it has no indications that it has been breached. Although the Sears investigation is ongoing, experts say there is a good chance the identification of Sears as a victim is a false alarm caused by a common weaknesses in banks’ anti-fraud systems that becomes apparent mainly in the wake of massive breaches like the one at Target late last year.

Earlier this week, rumors began flying that Sears was breached by the same sort of attack that hit Target. In December, Target disclosed that malware installed on its store cash registers compromised credit and debit card data on 40 some million transactions. This publication reached out on Wednesday to Sears to check the validity of those rumors, and earlier today Bloomberg moved a brief story saying that the U.S. Secret Service was said to be investigating a possible data breach at Sears.

But in a short statement issued today, Sears said the company has found no information indicating a breach at the company.

“There have been rumors and reports throughout the retail industry of security incidents at various retailers, and we are actively reviewing our systems to determine if we have been a victim of a breach,” Sears said in a written statement. “We have found no information based on our review of our systems to date indicating a breach.”

The Secret Service declined to comment.

Media stories about undisclosed breaches in the retail sector have fueled rampant speculation about the identities of other victim companies. Earlier this week, The Wall Street Journal ran a piece quoting Verizon Enterprise Solutions’s Bryan Sartin saying that the company — which investigates data breaches — was responding to two different currently undisclosed breaches at major retailers.

Interestingly, Sartin gave an interview last week to this publication specifically to discuss a potential blind spot in the approach used by most banks to identify companies that may have had a payment card breach — a weakness that he said almost exclusively manifests itself directly after large breaches like the Target break-in.

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Card Backlog Extends Pain from Target Breach

February 25, 2014

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Last week’s story about steeply falling prices on credit and debit card data stolen from Target mentioned several reasons why many banks may not have already reissued all of their cards impacted by the breach. But it left out one other key reason: A huge backlog of orders at companies that manufacture credit and debit cards on behalf of financial institutions.

Turns out, while the crooks responsible for monetizing the Target breach seem to have had little trouble counterfeiting stolen cards, the process by which banks obtain legitimate replacement cards for their customers is not always quite so speedy.

I recently spoke with a gentleman who heads up security at a small federal credit union, and this individual said his institution ended up printing their own cards in-house after being told by their financial services provider that their order for some 2,000 new customer cards compromised in the Target breach would have to get behind a backlog of more than 2 million existing orders from other banks.

The credit union in question issues Visa-branded cards to its customers, but the actual physical cards are produced by Fiserv, a Brookfield, Wisc. financial services firm that also handles the online banking portals for a huge number of small to mid-sized financial institutions nationwide. In addition to servicing this credit union, Fiserv also prints cards for some of the biggest banks in the world, including Bank of America and Chase.

Shortly after the holidays, the credit union began alerting affected customers, notifying them that the institution would soon be reissuing cards. But when it actually went to place the order for the new cards, the institution was told it would have to get in line.

“They informed us that there was a backlog of 2 million cards, and said basically, ‘We’ll get to you when we get to you’,” the credit union source told KrebsOnSecurity.

Murray Walton, chief risk officer at Fiserv, acknowledged that the company has experienced extraordinarily high demand for new cards in the wake of the Target breach, but that Fiserv is quickly whittling down its existing backlog of orders.

“A large breach injects additional demand into a system that is already operating at near-peak capacity at year-end,” Walton said. “As a result, producers face the challenge of juggling existing contractual commitments with this incremental demand, and turn to mandatory overtime and staff augmentation to get the most out of their equipment and infrastructure. We believe we are managing this situation as well as possible, and are beginning to see our cycle times (order to delivery) diminish compared to a few weeks ago. Meanwhile, we note that fraud prevention is a multi-faceted challenge, and card reissue is only one arrow in the quiver. Alert consumers and behind-the-scenes fraud management programs are also essential.”

Faced with mounting customer service requests from account holders who’d been told to expect new cards, the credit union decided to take matters into its own hands.

“We have the capability to print out the cards ourselves at a local branch, so some of our software developers wrote some scripts to export the customer data and we had two people who ended up burning the midnight oil for several days making these cards by hand.”

iOS Update Quashes Dangerous SSL Bug

February 23, 2014

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Apple on Friday released a software update to fix a serious security weakness in its iOS mobile operating system that allows attackers to read and modify encrypted communications on iPhones, iPads and other iOS devices. The company says it is working to produce a patch for the same flaw in desktop and laptop computers powered by its OS X operating system.

The update — iOS 7.0.6 — addresses a glaring vulnerability in the way Apple devices handle encrypted communications. The flaw allows an attacker to intercept, read or modify encrypted email, Web browsing, Tweets and other transmitted data, provided the attacker has control over the WiFi or cellular network used by the vulnerable device.

There has been a great deal of speculation and hand-waving about whether this flaw was truly a mistake or if it was somehow introduced intentionally as a backdoor. And it’s not yet clear how long this bug has been included in Apple’s software. In any case, if you have an iPhone or iPad or other iOS device, please take a moment to apply this fix.

Generally, I advise users to avoid downloading and installing security updates when they are using public WiFi or other untrusted networks. On the surface at least, it would seem that the irony of this situation for most users is that iOS devices will download updates automatically as long as users are connected to a WiFi network. But as several folks have already pointed out on Twitter, Apple uses code-signing on iOS and app updates to ensure that rogue code can’t be pushed to devices.

I will update this post when Apple ships the patch for OS X systems. For now, it may be wise to avoid using Safari on OS X systems. As Dan Goodin at Ars Technica writes, “because the Google Chrome and Mozilla Firefox browsers appear to be unaffected by the flaw, people should also consider using those browsers when possible, although they shouldn’t be considered a panacea.”

For a deeper dive on this vulnerability and its implications, check out this piece by Larry Seltzer at ZDNet, and this analysis by Google’s Adam Langley.

Update: Apple has fixed this and a number of other important issues with OS X, in this release.

Adobe, Microsoft Push Fixes For 0-Day Threats

February 20, 2014

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For the second time this month, Adobe has issued an emergency software update to fix a critical security flaw in its Flash Player software that attackers are already exploiting. Separately, Microsoft released a stopgap fix to address a critical bug in Internet Explorer versions 9 and 10 that is actively being exploited in the wild.

The vulnerabilities in both Flash and IE are critical, meaning users could get hacked just by visiting a compromised or booby-trapped Web site. The Flash patch comes just a little over two weeks after Adobe released a rush fix for another zero-day attack against Flash.

Adobe said in an advisory today that it is aware of an exploit that exists for one of three security holes that the company is plugging with this new release, which brings Flash Player to v. 12.0.0.70 for Linux, Mac and Windows systems.

This link will tell you which version of Flash your browser has installed. IE10/IE11 and Chrome should auto-update their versions of Flash, although IE users may need to check with the Windows Update feature built into the operating system.

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Fire Sale on Cards Stolen in Target Breach

February 19, 2014

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Last year’s breach at Target Corp. flooded underground markets with millions of stolen credit and debit cards. In the days surrounding the breach disclosure, the cards carried unusually high price tags — in large part because few banks had gotten around to canceling any of them yet. Today, two months after the breach, the number of unsold stolen cards that haven’t been cancelled by issuing banks is rapidly shrinking, forcing the miscreants behind this historic heist to unload huge volumes of cards onto underground markets and at cut-rate prices.

Cards stolen in the Target breach have become much cheaper as more of them come back declined or cancelled by issuing banks.

Earlier today, the underground card shop Rescator[dot]so moved at least 2.8 million cards stolen from U.S.-based shoppers during the Target breach. This chunk of cards, dubbed “Beaver Cage” by Rescator, was the latest of dozens of batches of cards stolen from Target that have gone on sale at the shop since early December.

The Beaver Cage batch of cards have fallen in price by as much as 70 percent compared to those in “Tortuga,” a huge chunk of several million cards stolen from Target that sold for between $26.60 and $44.80 apiece in the days leading up to Dec. 19 — the day that Target acknowledged a breach. Today, those same cards are now retailing for prices ranging from $8 to $28. The oldest batches of cards stolen in the Target breach –i.e., the first batches of stolen cards sold –are at the top of legend in the graphic above; the “newer,” albeit less fresh, batches are at the bottom.

The core reason for the price drop appears to be the falling “valid rate” associated with each batch. Cards in the Tortuga base were advertised as “100 percent valid,” meaning that customers who bought ten cards from the store could expect all 10 to work when they went to use them at retailers to purchase high-priced electronics, gift cards and other items that can be quickly resold for cash.

This latest batch of Beaver Cage cards, however, carries only a 60 percent valid rate, meaning that on average customers can expect at least 4 out of every 10 cards they buy to come back declined or canceled by the issuing bank.

The most previous batch of Beaver Cage cards — pushed out by Rescator on Feb. 6 — included nearly 4 million cards stolen from Target and carried a 65 percent valid rate. Prior to Beaver Cage, the Target cards were code-named “Eagle Claw.” On Jan. 29, Rescator debuted 4 million cards bearing the Eagle Claw name and a 70 percent valid rate. The first two batches of Eagle Claw-branded cards — a chunk of 2 million cards — were released on Jan. 21 with a reported 83 percent valid rate.

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Time to Harden Your Hardware?

February 18, 2014

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Most Internet users are familiar with the concept of updating software that resides on their computers. But this past week has seen alerts about an unusual number of vulnerabilities and attacks against some important and ubiquitous hardware devices, from consumer-grade Internet routers, data storage and home automation products to enterprise-class security solutions.

Last week, the SANS Internet Storm Center began publishing data about an ongoing attack from self-propagating malware that infects some home and small-office wireless routers from Linksys. The firewall built into routers can be a useful and hearty first line of protection against online attacks, because its job is to filter out incoming traffic that the user behind the firewall did not initiate. But things get dicier when users enable remote administration capability on these powerful devices, which is where this malware comes in.

The worm — dubbed “The Moon” — bypasses the username and password prompt on affected devices. According to Ars Technica’s Dan Goodin, The Moon has infected close to 1,000 Linksys E1000, E1200 and E2400 routers, although the actual number of hijacked devices worldwide could be higher and is likely to climb. In response, Linksys said the worm affects only those devices that have the Remote Management Access feature enabled, and that Linksys ships these products with that feature turned off by default. The Ars Technica story includes more information about how to tell whether your router may be impacted. Linksys says it’s working on an official fix for the problem, and in the meantime users can block this attack by disabling the router’s remote management feature.

Similarly, it appears that some ASUS routers — and any storage devices attached to them — may be exposed to anyone online without the need of login credentials if users have taken advantage of remote access features built into the routers, according to this Ars piece from Feb. 17. The danger in this case is with Asus router models including RT-AC66R, RT-AC66U, RT-N66R, RT-N66U, RT-AC56U, RT-N56R, RT-N56U, RT-N14U, RT-N16, and RT-N16R. Enabling any of the (by-default disabled) “AiCloud” options on the devices — such as “Cloud Disk” and “Smart Access” — opens up a potentially messy can of worms. More details on this vulnerability are available at this SecurityFocus writeup.

ASUS reportedly released firmware updates last week to address these bugs. Affected users can find the latest firmware updates and instructions for updating their devices by entering the model name/number of the device here. Alternatively, consider dumping the stock router firmware in favor of something more flexible, less buggy amd most likely more secure (see this section at the end of this post for more details).

YOUR LIGHTSWITCH DOES WHAT?

Belkin WeMo Switch

Outfitting a home or office with home automation tools that let you control and remotely monitor electronics can quickly turn into a fun and addictive (if expensive) hobby. But things get somewhat more interesting when the whole setup is completely exposed to anyone on the Internet. That’s basically what experts at IOActive found is the case with Belkin‘s WeMo family of home automation devices.

According to research released today, multiple vulnerabilities in these WeMo Home Automation tools give malicious hackers the ability to remotely control the devices over the Internet, perform malicious firmware updates, and access an internal home network. From IOActive’s advisory (PDF):

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Yours Truly Profiled in The New York Times

February 17, 2014

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Today’s New York Times features a profile of this author — a story titled, “Reporting from the Web’s Underbelly”. The piece, written by The Times’s Silicon Valley reporter Nicole Perlroth, observes:

Mr. Krebs, 41, tries to write pieces that cannot be found elsewhere. His widely read cybersecurity blog, Krebs on Security, covers a particularly dark corner of the Internet: profit-seeking cybercriminals, many based in Eastern Europe, who make billions off pharmaceutical sales, malware, spam, frauds and heists like the recent ones that Mr. Krebs was first to uncover at Adobe, Target and Neiman Marcus….

…Unlike physical crime — a bank robbery, for example, quickly becomes public — online thefts are hushed up by companies that worry the disclosure will inflict more damage than the theft, allowing hackers to raid multiple companies before consumers hear about it.

“There’s a lot going on in this industry that impedes the flow of information,” Mr. Krebs said. “And there’s a lot of money to be made in having intelligence and information about what’s going on in the underworld. It’s big business but most people don’t want to pay for it, which explains why they come to someone like me.”

The New Normal: 200-400 Gbps DDoS Attacks

February 14, 2014

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Over the past four years, KrebsOnSecurity has been targeted by countless denial-of-service attacks intended to knock it offline. Earlier this week, KrebsOnSecurity was hit by easily the most massive and intense such attack yet — a nearly 200 Gbps assault leveraging a simple attack method that industry experts say is becoming alarmingly common.

At issue is a seemingly harmless feature built into many Internet servers known as the Network Time Protocol (NTP), which is used to sync the date and time between machines on a network. The problem isn’t with NTP itself, per se, but with certain outdated or hard-coded implementations of it that attackers can use to turn a relatively negligible attack into something much, much bigger. Symantec‘s writeup on this threat from December 2013 explains the problem succinctly:

Similar to DNS amplification attacks, the attacker sends a small forged packet that requests a large amount of data be sent to the target IP Address. In this case, the attackers are taking advantage of the monlist command. Monlist is a remote command in older version of NTP that sends the requester a list of the last 600 hosts who have connected to that server. For attackers the monlist query is a great reconnaissance tool. For a localized NTP server it can help to build a network profile. However, as a DDoS tool, it is even better because a small query can redirect megabytes worth of traffic.

Matthew Prince, the CEO of Cloudflare — a company that helps Web sites stay online in the face of huge DDoS attacks — blogged Thursday about a nearly 400 Gbps attack that recently hit one of the company’s customers and leveraged NTP amplification. Prince said that while Cloudflare “generally [was] able to mitigate the attack, it was large enough that it caused network congestion in parts of Europe.”

“Monday’s DDoS proved these attacks aren’t just theoretical. To generate approximately 400Gbps of traffic, the attacker used 4,529 NTP servers running on 1,298 different networks,” Prince wrote. “On average, each of these servers sent 87Mbps of traffic to the intended victim on CloudFlare’s network. Remarkably, it is possible that the attacker used only a single server running on a network that allowed source IP address spoofing to initiate the requests. An attacker with a 1 Gbps connection can theoretically generate more than 200Gbps of DDoS traffic.” Continue reading →

Email Attack on Vendor Set Up Breach at Target

February 12, 2014

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The breach at Target Corp. that exposed credit card and personal data on more than 110 million consumers appears to have begun with a malware-laced email phishing attack sent to employees at an HVAC firm that did business with the nationwide retailer, according to sources close to the investigation.

Last week, KrebsOnSecurity reported that investigators believe the source of the Target intrusion traces back to network credentials that Target had issued to Fazio Mechanical, a heating, air conditioning and refrigeration firm in Sharpsburg, Pa. Multiple sources close to the investigation now tell this reporter that those credentials were stolen in an email malware attack at Fazio that began at least two months before thieves started stealing card data from thousands of Target cash registers.

Two of those sources said the malware in question was Citadel — a password-stealing bot program that is a derivative of the ZeuS banking trojan — but that information could not be confirmed. Through a PR firm, Fazio declined to answer direct questions for this story, and Target has declined to comment, citing an active investigation.

In a statement (PDF) issued last week, Fazio said it was “the victim of a sophisticated cyber attack operation,” and further that “our IT system and security measures are in full compliance with industry practices.”

There is no question that, like Target, Fazio Mechanical was the victim of cybercrime. But investigators close to the case took issue with Fazio’s claim that it was in full compliance with industry practices, and offered another explanation of why it took the Fazio so long to detect the email malware infection: The company’s primary method of detecting malicious software on its internal systems was the free version of Malwarebytes Anti-Malware.

To be clear, Malwarebytes Anti-Malware (MBAM) free is quite good at what it’s designed to do – scan for and eliminate threats from host machines. However, there are two problems with an organization relying solely on the free version of MBAM for anti-malware protection: Firstly, the free version is an on-demand scanner that does not offer real-time protection against threats (the Pro version of MBAM does include a real-time protection component). Secondly, the free version is made explicitly for individual users and its license prohibits corporate use.

Fazio’s statement also clarified that its data connection to Target was exclusively for electronic billing, contract submission and project management. The company did not specify which component(s) of Target’s online operations that Fazio accessed externally, but a former employee at Target said nearly all Target contractors access an external billing system called Ariba, as well as a Target project management and contract submissions portal called Partners Online. The source said Fazio also would have had access to Target’s Property Development Zone portal.

According to a former member of Target’s security team who asked not to be identified, when a work order for an external vendor is created, the payment is collected through the Ariba system: Vendors log into Ariba, complete the necessary steps to close out the work order and they are later paid. But how would the attackers have moved from Target’s external billing system into an internal portion of the network occupied by point-of-sale devices? The former Target network expert has a theory:

“I know that the Ariba system has a back end that Target administrators use to maintain the system and provide vendors with login credentials, [and] I would have to speculate that once a vendor logs into the portal they have active access to the server that runs the application,” the source said. “Most, if not almost all, internal applications at Target used Active Directory (AD) credentials and I’m sure the Ariba system was no exception. I wouldn’t say the vendor had AD credentials but that the internal administrators would use their AD login to access the system from inside. This would mean the sever had access to the rest of the corporate network in some form or another.”

Last week’s story about Fazio’s role in the attack on Target mentioned that Target could be facing steep fines if it was discovered that the company was not in compliance with payment card industry (PCI) security standards. Among those is a requirement that merchants incorporate two-factor authentication for remote network access originating from outside the network by personnel and all third parties.

Another source who managed Target vendors for a number of years until quite recently said that only “in rare cases” would Target have required a vendor to use a one-time token or other two-factor authentication approach.

“Only the vendors in the highest security group — those required to directly access confidential information — would be given a token, and instructions on how to access that portion of the network,” the source said, speaking on condition of anonymity. “Target would have paid very little attention to vendors like Fazio, and I would be surprised if there was ever even a basic security assessment done of those types of vendors by Target.”

But according to Avivah Litan, a fraud analyst at Gartner, Target wouldn’t have needed to require vendors to use two-factor logins if the company believed it had taken steps to isolate the vendor portals from its payment network.

“In fairness to Target, if they thought their network was properly segmented, they wouldn’t have needed to have two-factor access for everyone,” Litan said. “But if someone got in there and somehow escalated their Active Directory privileges like you described, that might have [bridged] that segmentation.”

OPEN-SOURCE INTEL

Many readers have questioned why the attackers would have picked on an HVAC firm as a conduit for hacking Target. The answer is that they probably didn’t, at least at first. Many of these email malware attacks start with shotgun attacks that blast out email far and wide; only after the attackers have had time to comb through the victim list for interesting targets do they begin to separate the wheat from the chaff.

But Target may have inadvertently made it easier for the attackers in this case, in part by leaving massive amounts of internal documentation for vendors on its various public-facing Web properties that do not require a login. Indeed, many of these documents would be a potential gold mine of information for an attacker.

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Security Updates for Shockwave, Windows

February 11, 2014

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Adobe and Microsoft today each issued patches to fix critical security flaws in their software. Microsoft’s February Patch Tuesday includes seven patch bundles addressing at least 31 vulnerabilities in Windows and related software. Adobe pushed out an update that fixes two critical bugs in its Shockwave Player.

More than half of the updates issued by Microsoft today earned a “critical” rating — Microsoft’s most dire. That rating is assigned to vulnerabilities that can be exploited by malware or malcontents to take complete, remote control over vulnerable systems — with no help from users.

Microsoft is urging Windows users to apply all of the available fixes, but for those who need to prioritize patches (organizations that typically test patches before deploying them enterprise-wide), Redmond places a special focus on MS14-007, a graphics vulnerability in Windows 7/8/8.1 and Windows Server 2007, 2012 and Windows RT.

The cumulative, critical security update for all versions of Internet Explorer (MS14-010) fixes two dozen vulnerabilities, including one that Microsoft says has already been publicly disclosed. The other patch that Microsoft specifically called out — MS14-011 — addresses a vulnerability in VBScript that could cause problems for IE users.

Microsoft also once again is encouraging Windows users who haven’t already done so to consider installing and using its Enhanced Mitigation Experience Toolkit (EMET), a free tool that can help to significantly beef up the security of third-party applications that run on top of Windows. I would second their recommendation, and have reviewed EMET 4.0 here. The latest version — 4.1 — is available at this link and requires Microsoft’s .NET Framework 4 platform.

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