Dropbox: Password Breach Led to Spam

July 31, 2012
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Two weeks ago, many Dropbox users began suspecting a data breach at the online file-sharing service after they started receiving spam at email addresses they’d created specifically for use at Dropbox. Today, the company confirmed that suspicion, blaming the incident on a Dropbox employee who had re-used his or her Dropbox password at another site that got hacked.

In a statement released on its blog this evening, DropBox’s Aditya Agarwal wrote:

Our investigation found that usernames and passwords recently stolen from other websites were used to sign in to a small number of Dropbox accounts. We’ve contacted these users and have helped them protect their accounts.

A stolen password was also used to access an employee Dropbox account containing a project document with user email addresses. We believe this improper access is what led to the spam. We’re sorry about this, and have put additional controls in place to help make sure it doesn’t happen again.

A Dropbox spokeswoman said the company is not ready to disclose just how many user account credentials may have been compromised by this password oops, noting that the investigation is still ongoing.

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Email-Based Malware Attacks, July 2012

July 31, 2012
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Last month’s post examining the top email-based malware attacks received so much attention and provocative feedback that I thought it was worth revisiting. I assembled it because victims of cyberheists rarely discover or disclose how they got infected with the Trojan that helped thieves siphon their money, and I wanted to test conventional wisdom about the source of these attacks.

Top malware attacks and their antivirus detection rates, past 30 days. Source: UAB

While the data from the past month again shows why that wisdom remains conventional, I believe the subject is worth periodically revisiting because it serves as a reminder that these attacks can be stealthier than they appear at first glance.

The threat data draws from daily reports compiled by the computer forensics and security management students at the University of Alabama at Birmingham. The UAB reports track the top email-based threats from each day, and include information about the spoofed brand or lure, the method of delivering the malware, and links to Virustotal.com, which show the number of antivirus products that detected the malware as hostile (virustotal.com scans any submitted file or link using about 40 different antivirus and security tools, and then provides a report showing each tool’s opinion).

As the chart I compiled above indicates, attackers are switching the lure or spoofed brand quite often, but popular choices include such household names as American Airlines, Ameritrade, Craigslist, Facebook, FedEx, Hewlett-Packard (HP), Kraft, UPS and Xerox. In most of the emails, the senders spoofed the brand name in the “from:” field, and used embedded images stolen from the brands being spoofed.

The one detail most readers will probably focus on most this report is the atrociously low detection rate for these spammed malware samples. On average, antivirus software detected these threats about 22 percent of the time on the first day they were sent and scanned at virustotal.com. If we take the median score, the detection rate falls to just 17 percent. That’s actually down from last month’s average and median detection rates, 24.47 percent and 19 percent, respectively.

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Tagging and Tracking Espionage Botnets

July 30, 2012
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A security researcher who’s spent 18 months cataloging and tracking malicious software that was developed and deployed specifically for spying on governments, activists and industry executives says the complexity and scope of these cyberspy networks now rivals many large conventional cybercrime operations.

Joe Stewart, senior director of malware research at Atlanta-based Dell SecureWorks, said he’s tracked more than 200 unique families of custom malware used in cyber-espionage campaigns. He also uncovered some 1,100 Web site names registered by cyberspies for hosting networks used to control the malware, or for “spear phishing,” highly targeted emails that spread the malware.

Although those numbers may seem low in the grand scheme of things (antivirus companies now deal with many tens of thousands of new malware samples each day), almost everything about the way these cyberspying networks are put together seems designed to mask the true scope of the operations, he found. For instance, Stewart discovered that the attackers set up almost 20,000 subdomains on those 1,100 domain names; but these subdomains were used for controlling or handing out new malware for botnets that each only controlled a few hundred computers at a time.

“Unlike the largest cybercrime networks that can contain millions of infected computers in a single botnet, cyber-espionage encompasses tens of thousands of infected computers spread across hundreds of botnets,” Stewart wrote in a paper released at last week’s Black Hat security convention in Las Vegas. “So each botnet…tends to look like a fairly small-scale operation. But this belies the fact that for every [cyber-espionage] botnet that is discovered and publicized, hundreds more continue to lie undetected on thousands of networks.”

Once you get past all the technical misdirection built into the malware networks by its architects, Stewart said, the infrastructure that frames these spy machines generally points in one of two directions: one group’s infrastructure points back to Shanghai, the other to Beijing.

“There have to be hundreds of people involved, just to maintain this amount of infrastructure and this much activity and this many spear phishes, collecting so many documents, and writing this much malware,” Stewart said. “But when it comes time to grouping them, that’s when it gets harder. What I can tell from the clustering I’m doing here is that there are two major groups in operation. Some have dozens of different malware families that they use, but many will share a common botnet command and control infrastructure.”

Domains connected to different cyber-espionage botnets typically trace back to one of two destinations in China, according to Dell SecureWorks.

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ATM Skimmers Get Wafer Thin

July 24, 2012
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It’s getting harder to detect some of the newer ATM skimmers, fraud devices attached to or inserted into cash machines and designed to steal card and PIN data. Among the latest and most difficult-to-spot skimmer innovations is a wafer-thin card reading device that can be inserted directly into the ATM’s card acceptance slot.

That’s according to two recent reports from the European ATM Security Team (EAST), an organization that collects ATM fraud reports from countries in the region. In both reports, EAST said one country (it isn’t naming which) alerted them about a new form of skimming device that is thin enough to be inserted directly into the card reader slot. These devices record the data stored on the magnetic stripe on the back of the card as it is slid into a compromised ATM.

Wafer-thin skimmers like these are showing up in ATMs in one European nation. Images courtesy EAST.

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DoItQuick: Fast Domains for Dirty Deeds

July 23, 2012
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A new service offered in the cybercriminal underground is geared toward spammers, scammers and malware purveyors interested in mass-registering dozens of dodgy domains in one go.

DoItQuick offers mass registration of malware domains.

The service — doitquick.net — will auto-register up to 15 domains simultaneously, choosing randomly named domains unless the customer specifies otherwise. DoItQuick sells two classes of domains: “white” domains that are “guaranteed” to stay registered for at least a year; and “black” domains that customers can use for illicit purposes and expect to last between 2 and 30 days before they are canceled.

This service makes it quite clear why customers might prefer the “black” domain registration service: “Domains for black deeds – these domains are registered for limited terms, from 2 to 30 days (average duration is about a week). Such domains are used for black and gray deeds. Low prices, fast registration! It is ideal for redirects, exploit packs, traffic, flood, botnets and other similar stuff. Domain names are checked for getting into blacklists, trackers and Spamhaus.”

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Top Spam Botnet, “Grum,” Unplugged

July 19, 2012
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Nearly four years after it burst onto the malware scene, the notorious Grum spam botnet has been disconnected from the Internet. Grum has consistently been among the top three biggest spewers of junk email, a crime machine capable of blasting 18 billion messages per day and responsible for sending about one-third of all spam.

Source: Symantec Message Labs

The takedown, while long overdue, is another welcome example of what the security industry can accomplish cooperatively and without the aid of law enforcement officials. Early press coverage of this event erroneously attributed part of the takedown to Dutch authorities, but police in the Netherlands said they were not involved in this industry-led effort.

The Grum ambush began in earnest several weeks ago at the beginning of July, following an analysis published by security firm FireEye, a Milpitas, Calif. based company that has played a big role in previous botnet takedowns, including Mega-D/Ozdok, Rustock, Srizbi.

Atif Mushtaq, senior staff scientist at FireEye, said the company had some initial success in notifying ISPs that were hosting control networks for Grum: The Dutch ISP Ecatel responded favorably, yanking the plug on two control servers. But Mushtaq said the ISPs where Grum hosted its other control servers — networks in Russia and Panama — proved harder to convince.

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Cyberheist Smokescreen: Email, Phone, SMS Floods

July 18, 2012
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It was early October 2011, and I was on the treadmill checking email from my phone when I noticed several hundred new messages had arrived since I last looked at my Gmail inbox just 20 minutes earlier. I didn’t know it at the time, but my account was being used to beta test a private service now offered openly in the criminal underground that can be hired to create highly disruptive floods of junk email, text messages and phone calls.

Many businesses request some kind of confirmation from their bank whenever high-dollar transfers are initiated. These confirmations may be sent via text message or email, or the business may ask their bank to call them to verify requested transfers. The attack that hit my inbox was part of an offering that crooks can hire to flood each medium of communication, thereby preventing a targeted business from ever receiving or finding alerts from their bank.

Shortly after the email barrage began, I fired off a note to Google‘s public relations folks, asking for advice and assistance. Thankfully, my phone line was not a subject of the attack, and I was able to communicate what I was seeing to Google’s team. They worked to fight the attack for the better part of that day, during which time my inbox received tens of thousands of emails, burying hundreds of legitimate emails in page after page of junk messages (in the screen shot above, the note to Google spokesman Jay Nancarrow is at the top of the junk message pile).

What was most surprising about these messages was that many of them contained fairly spammy subject lines that should have been easily caught by Google’s junk mail filters. Each junk message contained nothing but pages full of garbled letters and numbers; the text of each missive resembled an encrypted message.

Google’s engineers managed to block a majority of the junk messages after about six hours, but the company declined to talk about what caused the attack to succeed. It took many more hours to sift through the junk messages to fish out the ones I wanted.

“This isn’t about a hole in Gmail or an exploit — it’s more a matter of spam dynamics and what may be able to get through more easily under certain circumstances,” Nancarrow said. “As a result, we can’t provide specifics that could aid spammers in trying new campaigns.”

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Spammers Target Dropbox Users

July 17, 2012
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“Always have your stuff when you need it with Dropbox.” That’s the marketing line for the online file storage service, but today users have had difficulty logging into the service. The outages came amid reports that many European Dropbox users were being blasted with spam for online casinos, suggesting some kind of leak of Dropbox user email addresses.

The trouble began earlier today, when users on the Dropbox support forums began complaining of suddenly receiving spam at email addresses they’d created specifically for use with Dropbox. Various users in Germany, the Netherlands and United Kingdom reported receiving junk email touting online gambling sites.

Dropbox did not respond to emails seeking comment, but a forum user who self-identified as a company employee said Dropbox was investigating the reports.

At around 3 p.m. ET, the company’s service went down in a rare outage, blocking users from logging into and accessing their files and displaying an error message on dropbox.com. I will update this post in the event that the company responds to my requests or provides some explanation of what caused today’s outage and the spam.

The outage and strange spam runs follow a week of high profile password and data breaches. Yahoo! acknowledged that more than 400,000 user names and passwords to Yahoo and other companies were stolen last Wednesday. Formspring, a social question-and-answer site, reset all user passwords after it discovered that approximately 420,000 password hashes from its servers had been posted to an online forum last Monday. Androidforums.com and Billabong International also disclosed password breaches last week.

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How to Break Into Security, Bejtlich Edition

July 17, 2012
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For this fourth installment of advice columns aimed at people who are interested in learning more about security as a craft or profession, I reached out to Richard Bejtlich, a prominent security blogger who last year moved from a job as director of incident response at General Electric to chief security officer at security forensics firm Mandiant.

Bejtlich responded with a practical how-to for a security novice looking to try on both attacker and defender hats. Without further ado…

Bejtlich: Providing advice on “getting started in digital security” is similar to providing advice on “getting started in medicine.” If you ask a neurosurgeon he or she may propose some sort of experiment with dead frog legs and batteries. If you ask a dermatologist you might get advice on protection from the sun whenever you go outside. Asking a “security person” will likewise result in many different responses, depending on the individual’s background and tastes.

Rather than try to devise a thorough curriculum that provides balanced coverage of the dozen or more distinct disciplines that one might call “digital security,” this article covers one aspect: magic. More specifically, this advice strives to dispel the notion that digital security is a realm where only magicians can perform superhuman feats involving computers and data. Rather, the point is to provide a way for beginners to get a feel for convincing a computer to take actions probably not expected by its original programmers. For those with a more technical inclination, the article provides a means to watch what is happening at the network level.

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Spy Software Aims to Corral Money Mules

July 16, 2012
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Borrowing from the playbook of corporations seeking better ways to track employee productivity, some cybercriminal gangs are investing in technologies that help them keep closer tabs on their most prized assets: “Money mules,” individuals willingly or unwittingly recruited to help fraudsters launder stolen funds. It seems that at least one mule recruitment gang employs custom software to spy on new recruits.

Last month, I heard from a reader in North Carolina named John who’d been roped into working for a company that claimed to be in the digital concierge and outsourcing business. John became suspicious that he was involved in something shady when they told him he should expect a transfer of nearly $10,000 to the personal bank account that he’d provided to his erstwhile employer in order to eventually receive a paycheck.

The software stole this glimpse of my test machine’s desktop.

The firm that hired John, a fictitious company called VIP One, recruits mules to help process fraudulent transfers from businesses victimized by account takeovers. Prior to sending its mules money, VIP One has prospective mules spend several weeks doing relatively meaningless busy work, for which they are promised payment at the end of the month.

VIP One requires all new recruits to install a “time tracking” application, basically a digital stopwatch that employees are expected to use to keep track of their time “on the job.” John was kind enough to let me take a peek inside his account at VIP One, and to download the time tracking software. It’s safe to say that time is certainly not the only thing being tracked by this program.

I installed the application in a Window XP virtual machine equipped with Wireshark, a free program that lets you inspect the data packets going in and out of a host machine. I pressed start and left the software alone for a few hours. A review of the Wireshark logs showed that the time tracking tool periodically and surreptitiously took screenshots of my system, uploading them to a site called gyazo.com. This Web site appears to be associated with a legitimate screen-grabbing application that automates the grabbing and posting online of screen captures.

My test machine also had several peripherals plugged into it, including a Webcam. To my surprise, further review of the logs showed that the time tracking tool hijacked my machine’s Web cam and took several pictures, also posting them to gyazo.com.

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