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Bitcoin Blackmail by Snail Mail Preys on Those with Guilty Conscience

KrebsOnSecurity heard from a reader whose friend recently received a remarkably customized extortion letter via snail mail that threatened to tell the recipient’s wife about his supposed extramarital affairs unless he paid $3,600 in bitcoin. The friend said he had nothing to hide and suspects this is part of a random but well-crafted campaign to prey on men who may have a guilty conscience.

The letter addressed the recipient by his first name and hometown throughout, and claimed to have evidence of the supposed dalliances.

“You don’t know me personally and nobody hired me to look into you,” the letter begins. “Nor did I go out looking to burn you. It is just your bad luck that I stumbled across your misadventures while working on a job around Bellevue.”

The missive continues:

“I then put in more time than I probably should have looking into your life. Frankly, I am ready to forget all about you and let you get on with your life. And I am going to give you two options that will accomplish that very thing. These two options are to either ignore this letter, or simply pay me $3,600. Let’s examine those two options in more detail.”

The letter goes on to say that option 1 (ignoring the threat) means the author will send copies of his alleged evidence to the man’s wife and to her friends and family if he does not receive payment within 12 days of the letter’s post marked date.

“So [name omitted], even if you decide to come clean with your wife, it won’t protect her from the humiliation she will feel when her friends and family find out your sordid details from me,” the extortionist wrote.

Option 2, of course, involves sending $3,600 in Bitcoin to an address specified in the letter. That bitcoin address does not appear to have received any payments. Attached to the two-sided extortion note is a primer on different ways to quickly and easily obtain bitcoin.

“If I don’t receive the bitcoin by that date, I will go ahead and release the evidence to everyone,” the letter concludes. “If you go that route, then the least you could do is tell your wife so she can come up with an excuse to prepare her friends and family before they find out. The clock is ticking, [name omitted].”

Of course, sending extortion letters via postal mail is mail fraud, a crime which carries severe penalties (fines of up to $1 million and up to 30 years in jail). However, as the extortionist rightly notes in his letter, the likelihood that authorities would ever be able to catch him is probably low.

The last time I heard of or saw this type of targeted extortion by mail was in the wake of the 2015 breach at online cheating site AshleyMadison.com. But those attempts made more sense to me since obviously many AshleyMadison users quite clearly did have an affair to hide.

In any case, I’d wager that this scheme — assuming that the extortionist is lying and has indeed sent these letters to targets without actual knowledge of extramarital affairs on the part of the recipients — has a decent chance of being received by someone who really does have a current or former fling that he is hiding from his spouse. Whether that person follows through and pays the extortion, though, is another matter.

I searched online for snippets of text from the extortion letter and found just one other mention of what appears to be the same letter: It was targeting people in Wellesley, Mass, according to a local news report from December 2017.

According to that report, the local police had a couple of residents drop off letters or call to report receiving them, “but to our knowledge no residents have fallen prey to the scam. The envelopes have no return address and are postmarked out of state, but from different states. The people who have notified us suspected it was a scam and just wanted to let us know.”

In the Massachusetts incidents, the extortionist was asking for $8,500 in bitcoin. Assuming it is the same person responsible for sending this letter, perhaps the extortionist wasn’t getting many people to bite and thus lowered his “fee.”

I opted not to publish a scan of the letter here because it was double-sided and redacting names, etc. gets dicey thanks to photo and image manipulation tools. Here’s a transcription of it instead (PDF).

Source: KREBS ON SECURITY

Microsoft’s Jan. 2018 Patch Tuesday Lowdown

Microsoft on Tuesday released 14 security updates, including fixes for the Spectre and Meltdown flaws detailed last week, as well as a zero-day vulnerability in Microsoft Office that is being exploited in the wild. Separately, Adobe pushed a security update to its Flash Player software.

Last week’s story, Scary Chip Flaws Raise Spectre of Meltdown, sought to explain the gravity of these two security flaws present in most modern computers, smartphones, tablets and mobile devices. The bugs are thought to be mainly exploitable in chips made by Intel and ARM, but researchers said it was possible they also could be leveraged to steal data from computers with chips made by AMD.

By the time that story had published, Microsoft had already begun shipping an emergency update to address the flaws, but many readers complained that their PCs experienced the dreaded “blue screen of death” (BSOD) after applying the update. Microsoft warned that the BSOD problems were attributable to many antivirus programs not yet updating their software to play nice with the security updates.

On Tuesday, Microsoft said it was suspending the patches for computers running AMD chipsets.

“After investigating, Microsoft determined that some AMD chipsets do not conform to the documentation previously provided to Microsoft to develop the Windows operating system mitigations to protect against the chipset vulnerabilities known as Spectre and Meltdown,” the company said in a notice posted to its support site.

“To prevent AMD customers from getting into an unbootable state, Microsoft has temporarily paused sending the following Windows operating system updates to devices that have impacted AMD processors,” the company continued. “Microsoft is working with AMD to resolve this issue and resume Windows OS security updates to the affected AMD devices via Windows Update and WSUS as soon as possible.”

In short, if you’re running Windows on a computer powered by an AMD, you’re not going to be offered the Spectre/Meltdown fixes for now. Not sure whether your computer has an Intel or AMD chip? Most modern computers display this information (albeit very briefly) when the computer first starts up, before the Windows logo appears on the screen.

Here’s another way. From within Windows, users can find this information by pressing the Windows key on the keyboard and the “Pause” key at the same time, which should open the System Properties feature. The chip maker will be displayed next to the “Processor:” listing on that page.

Microsoft also on Tuesday provided more information about the potential performance impact on Windows computers after installing the Spectre/Meltdown updates. To summarize, Microsoft said Windows 7, 8.1 and 10 users on older chips (circa 2015 or older), as well as Windows server users on any silicon, are likely to notice a slowdown of their computer after applying this update.

Any readers who experience a BSOD after applying January’s batch of updates may be able to get help from Microsoft’s site: Here are the corresponding help pages for Windows 7, Windows 8.1 and Windows 10 users.

As evidenced by this debacle, it’s a good idea to get in the habit of backing up your system on a regular basis. I typically do this at least once a month — but especially right before installing any updates from Microsoft. 

Attackers could exploit a zero-day vulnerability in Office (CVE-2018-0802) just by getting a user to open a booby-trapped Office document or visit a malicious/hacked Web site. Microsoft also patched a flaw (CVE-2018-0819) in Office for Mac that was publicly disclosed prior to the patch being released, potentially giving attackers a heads up on how to exploit the bug.

Of the 56 vulnerabilities addressed in the January Patch Tuesday batch, at least 16 earned Microsoft’s critical rating, meaning attackers could exploit them to gain full access to Windows systems with little help from users. For more on Tuesday’s updates from Microsoft, check out blogs from Ivanti and Qualys.

As per usual, Adobe issued an update for Flash Player yesterday. The update brings Flash to version 28.0.0.137 on Windows, Mac, and Linux systems. Windows users who browse the Web with anything other than Internet Explorer may need to apply the Flash patch twice, once with IE and again using the alternative browser (Firefox, Opera, e.g.).

Chrome and IE should auto-install the latest Flash version on browser restart (users may need to manually check for updates and/or restart the browser to get the latest Flash version). Chrome users may need to restart the browser to install or automatically download the latest version.

When in doubt, click the vertical three dot icon to the right of the URL bar, select “Help,” then “About Chrome”: If there is an update available, Chrome should install it then. Chrome will replace that three dot icon with an up-arrow inside of a circle when updates are waiting to be installed.

Standard disclaimer: Because Flash remains such a security risk, I continue to encourage readers to remove or hobble Flash Player unless and until it is needed for a specific site or purpose. More on that approach (as well as slightly less radical solutions ) can be found in A Month Without Adobe Flash Player. The short version is that you can probably get by without Flash installed and not miss it at all.

For readers still unwilling to cut the Flash cord, there are half-measures that work almost as well. Fortunately, disabling Flash in Chrome is simple enough. Paste “chrome://settings/content” into a Chrome browser bar and then select “Flash” from the list of items. By default it should be set to “Ask first” before running Flash, although users also can disable Flash entirely here or whitelist and blacklist specific sites.

Another, perhaps less elegant, solution is to keep Flash installed in a browser that you don’t normally use, and then to only use that browser on sites that require it.

Source: KREBS ON SECURITY

Website Glitch Let Me Overstock My Coinbase

Coinbase and Overstock.com just fixed a serious glitch that allowed Overstock customers to buy any item at a tiny fraction of the listed price. Potentially more punishing, the flaw let anyone paying with bitcoin reap many times the authorized bitcoin refund amount on any canceled Overstock orders.

In January 2014, Overstock.com partnered with Coinbase to let customers pay for merchandise using bitcoin, making it among the first of the largest e-commerce vendors to accept the virtual currency.

On December 19, 2017, as the price of bitcoin soared to more than $17,000 per coin, Coinbase added support for Bitcoin Cash — an offshoot (or “fork”) from bitcoin designed to address the cryptocurrency’s scalability challenges.

As a result of the change, Coinbase customers with balances of bitcoin at the time of the fork were given an equal amount of bitcoin cash stored by Coinbase. However, there is a significant price difference between the two currencies: A single bitcoin is worth almost $15,000 right now, whereas a unit of bitcoin cash is valued at around $2,400.

On Friday, Jan. 5, KrebsOnSecurity was contacted by JB Snyder, owner of North Carolina-based Bancsec, a company that gets paid to break into banks and test their security. An early adopter of bitcoin, Snyder said he was using some of his virtual currency to purchase an item at Overstock when he noticed something alarming.

During the checkout process for those paying by bitcoin, Overstock.com provides the customer a bitcoin wallet address that can be used to pay the invoice and complete the transaction. But Snyder discovered that Overstock’s site just as happily accepted bitcoin cash as payment, even though bitcoin cash is currently worth only about 15 percent of the value of bitcoin.

To confirm and replicate Snyder’s experience firsthand, KrebsOnSecurity purchased a set of three outdoor solar lamps from Overstock for a grand total of $78.27.

The solar lights I purchased from Overstock.com to test Snyder’s finding. They cost $78.27 in bitcoin, but because I was able to pay for them in bitcoin cash I only paid $12.02.

After indicating I wished to pay for the lamps in bitcoin, the site produced a payment invoice instructing me to send exactly 0.00475574 bitcoins to a specific address.

The payment invoice I received from Overstock.com.

Logging into Coinbase, I took the bitcoin address and pasted that into the “pay to:” field, and then told Coinbase to send 0.00475574 in bitcoin cash instead of bitcoin. The site responded that the payment was complete. Within a few seconds I received an email from Overstock congratulating me on my purchase and stating that the items would be shipped shortly.

I had just made a $78 purchase by sending approximately USD $12 worth of bitcoin cash. Crypto-currency alchemy at last!

But that wasn’t the worst part. I didn’t really want the solar lights, but also I had no interest in ripping off Overstock. So I cancelled the order. To my surprise, the system refunded my purchase in bitcoin, not bitcoin cash!

Consider the implications here: A dishonest customer could have used this bug to make ridiculous sums of bitcoin in a very short period of time. Let’s say I purchased one of the more expensive items for sale on Overstock, such as this $100,000, 3-carat platinum diamond ring. I then pay for it in Bitcoin cash, using an amount equivalent to approximately 1 bitcoin ($~15,000).

Then I simply cancel my order, and Overstock/Coinbase sends me almost $100,000 in bitcoin, netting me a tidy $85,000 profit. Rinse, wash, repeat.

Reached for comment, Overstock.com said the company changed no code in its site and that a fix implemented by Coinbase resolved the issue.

“We were made aware of an issue affecting cryptocurrency transactions and refunds by an independent researcher. After working with the researcher to confirm the finding, that method of payment was disabled while we worked with our cryptocurrency integration partner, Coinbase, to ensure they resolved the issue. We have since confirmed that the issue described in the finding has been resolved, and the cryptocurrency payment option has been re-enabled.”

Coinbase said “the issue was caused by the merchant partner improperly using the return values in our merchant integration API. No other Coinbase customer had this problem.”Coinbase told me the bug only existed for approximately three weeks.”

“After being made aware of an issue in our joint refund processing code on SaturdayCoinbase and Overstock worked together to deploy a fix within hours,” The Coinbase statement continued. “While a patch was being developed and tested, orders were proactively disabled to protect customers. To our knowledge, a very small number of transactions were impacted by this issue. Coinbase actively works with merchant partners to identify and solve issues like this in an ongoing, collaborative manner and since being made aware of this have ensured that no other partners are affected.”

Bancsec’s Snyder and I both checked for the presence of this glitch at multiple other merchants that work directly with Coinbase in their checkout process, but we found no other examples of this flaw.

The snafu comes as many businesses that have long accepted bitcoin are now distancing themselves from the currency thanks to the recent volatility in bitcoin prices and associated fees.

Earlier this week, it emerged that Microsoft had ceased accepting payments in Bitcoin, citing volatility concerns. In December, online game giant Steam said it was dropping support for bitcoin payments for the same reason.

And, as KrebsOnSecurity noted last month, even cybercriminals who run online stores that sell stolen identities and credit cards are urging their customers to transact in something other than bitcoin.

Interestingly, bitcoin is thought to have been behind a huge jump in Overstock’s stock price in 2017. In December, Overstock CEO Patrick Byrne reportedly stoked the cryptocurrency fires when he said that he might want to sell Overstock’s e-tailing operations and pour the extra cash into accelerating his blockchain-based business ideas instead.

In case anyone is wondering what I did with the “profit” I made from this scheme, I offered to send it back to Overstock, but they told me to keep it. Instead, I donated it to archive.org, a site that has come in handy for many stories published here.

Update, 3:15 p.m. ET: A previous version of this story stated that neither Coinbase nor Overstock would say which of the two was responsible for this issue. The modified story above resolves that ambiguity.

Source: KREBS ON SECURITY