Latest Warnings


17
Nov 20

Be Very Sparing in Allowing Site Notifications

An increasing number of websites are asking visitors to approve “notifications,” browser modifications that periodically display messages on the user’s mobile or desktop device. In many cases these notifications are benign, but several dodgy firms are paying site owners to install their notification scripts and then selling that communications pathway to scammers and online hucksters.

Notification prompts in Firefox (left) and Google Chrome.

When a website you visit asks permission to send notifications and you approve the request, the resulting messages that pop up appear outside of the browser. For example, on Microsoft Windows systems they typically show up in the bottom right corner of the screen — just above the system clock. These so-called “push notifications” rely on an Internet standard designed to work similarly across different operating systems and web browsers.

But many users may not fully grasp what they are consenting to when they approve notifications, or how to tell the difference between a notification sent by a website and one made to appear like an alert from the operating system or another program that’s already installed on the device.

This is evident by the apparent scale of the infrastructure behind a relatively new company based in Montenegro called PushWelcome, which advertises the ability for site owners to monetize traffic from their visitors. The company’s site currently is ranked by Alexa.com as among the top 2,000 sites in terms of Internet traffic globally.

Website publishers who sign up with PushWelcome are asked to include a small script on their page which prompts visitors to approve notifications. In many cases, the notification approval requests themselves are deceptive — disguised as prompts to click “OK” to view video material, or as “CAPTCHA” requests designed to distinguish automated bot traffic from real visitors.

An ad from PushWelcome touting the money that websites can make for embedding their dodgy push notifications scripts.

Approving notifications from a site that uses PushWelcome allows any of the company’s advertising partners to display whatever messages they choose, whenever they wish to, and in real-time. And almost invariably, those messages include misleading notifications about security risks on the user’s system, prompts to install other software, ads for dating sites, erectile disfunction medications, and dubious investment opportunities.

That’s according to a deep analysis of the PushWelcome network compiled by Indelible LLC, a cybersecurity firm based in Portland, Ore. Frank Angiolelli, vice president of security at Indelible, said rogue notifications can be abused for credential phishing, as well as foisting malware and other unwanted applications on users.

“This method is currently being used to deliver something akin to adware or click fraud type activity,” Angiolelli said. “The concerning aspect of this is that it is so very undetected by endpoint security programs, and there is a real risk this activity can be used for much more nefarious purposes.”

Sites affiliated with PushWelcome often use misleading messaging to trick people into approving notifications.

Continue reading →


28
Oct 20

FBI, DHS, HHS Warn of Imminent, Credible Ransomware Threat Against U.S. Hospitals

On Monday, Oct. 26, KrebsOnSecurity began following up on a tip from a reliable source that an aggressive Russian cybercriminal gang known for deploying ransomware was preparing to disrupt information technology systems at hundreds of hospitals, clinics and medical care facilities across the United States. Today, officials from the FBI and the U.S. Department of Homeland Security hastily assembled a conference call with healthcare industry executives warning about an “imminent cybercrime threat to U.S. hospitals and healthcare providers.”

The agencies on the conference call, which included the U.S. Department of Health and Human Services (HHS), warned participants about “credible information of an increased and imminent cybercrime threat to US hospitals and healthcare providers.”

The agencies said they were sharing the information “to provide warning to healthcare providers to ensure that they take timely and reasonable precautions to protect their networks from these threats.”

The warning came less than two days after this author received a tip from Alex Holden, founder of Milwaukee-based cyber intelligence firm Hold Security. Holden said he saw online communications this week between cybercriminals affiliated with a Russian-speaking ransomware group known as Ryuk in which group members discussed plans to deploy ransomware at more than 400 healthcare facilities in the U.S.

One participant on the government conference call today said the agencies offered few concrete details of how healthcare organizations might better protect themselves against this threat actor or purported malware campaign.

“They didn’t share any IoCs [indicators of compromise], so it’s just been ‘patch your systems and report anything suspicious’,” said a healthcare industry veteran who sat in on the discussion.

However, others on the call said IoCs may be of little help for hospitals that have already been infiltrated by Ryuk. That’s because the malware infrastructure used by the Ryuk gang is often unique to each victim, including everything from the Microsoft Windows executable files that get dropped on the infected hosts to the so-called “command and control” servers used to transmit data between and among compromised systems.

Nevertheless, cybersecurity incident response firm Mandiant today released a list of domains and Internet addresses used by Ryuk in previous attacks throughout 2020 and up to the present day. Mandiant refers to the group by the threat actor classification “UNC1878,” and aired a webcast today detailing some of Ryuk’s latest exploitation tactics.

Charles Carmakal, senior vice president for Mandiant, told Reuters that UNC1878 is one of most brazen, heartless, and disruptive threat actors he’s observed over the course of his career.

“Multiple hospitals have already been significantly impacted by Ryuk ransomware and their networks have been taken offline,” Carmakal said. Continue reading →


15
Oct 20

Breach at Dickey’s BBQ Smokes 3M Cards

One of the digital underground’s most popular stores for peddling stolen credit card information began selling a batch of more than three million new card records this week. KrebsOnSecurity has learned the data was stolen in a lengthy data breach at more than 100 Dickey’s Barbeque Restaurant locations around the country.

An ad on the popular carding site Joker’s Stash for “BlazingSun,” which fraud experts have traced back to a card breach at Dickey’s BBQ.

On Monday, the carding bazaar Joker’s Stash debuted “BlazingSun,” a new batch of more than three million stolen card records, advertising “valid rates” of between 90-100 percent. This is typically an indicator that the breached merchant is either unaware of the compromise or has only just begun responding to it.

Multiple companies that track the sale in stolen payment card data say they have confirmed with card-issuing financial institutions that the accounts for sale in the BlazingSun batch have one common theme: All were used at various Dickey’s BBQ locations over the past 13-15 months.

KrebsOnSecurity first contacted Dallas-based Dickey’s on Oct. 13. Today, the company shared a statement saying it was aware of a possible payment card security incident at some of its eateries:

“We received a report indicating that a payment card security incident may have occurred. We are taking this incident very seriously and immediately initiated our response protocol and an investigation is underway. We are currently focused on determining the locations affected and time frames involved. We are utilizing the experience of third parties who have helped other restaurants address similar issues and also working with the FBI and payment card networks. We understand that payment card network rules generally provide that individuals who timely report unauthorized charges to the bank that issued their card are not responsible for those charges.”

The confirmations came from Miami-based Q6 Cyber and Gemini Advisory in New York City.

Q6Cyber CEO Eli Dominitz said the breach appears to extend from May 2019 through September 2020.

“The financial institutions we’ve been working with have already seen a significant amount of fraud related to these cards,” Dominitz said.

Gemini says its data indicated some 156 Dickey’s locations across 30 states likely had payment systems compromised by card-stealing malware, with the highest exposure in California and Arizona. Gemini puts the exposure window between July 2019 and August 2020.

“Low-and-slow” aptly describes the card breach at Dickie’s, which persisted for at least 13 months.

With the threat from ransomware attacks grabbing all the headlines, it may be tempting to assume plain old credit card thieves have moved on to more lucrative endeavors. Alas, cybercrime bazaars like Joker’s Stash have continued plying their trade, undeterred by a push from the credit card associations to encourage more merchants to install credit card readers that require more secure chip-based payment cards.

That’s because there are countless restaurants — usually franchise locations of an established eatery chain — that are left to decide for themselves whether and how quickly they should make the upgrades necessary to dip the chip versus swipe the stripe.

“Dickey’s operates on a franchise model, which often allows each location to dictate the type of point-of-sale (POS) device and processors that they utilize,” Gemini wrote in a blog post about the incident. “However, given the widespread nature of the breach, the exposure may be linked to a breach of the single central processor, which was leveraged by over a quarter of all Dickey’s locations.” Continue reading →


21
Aug 20

FBI, CISA Echo Warnings on ‘Vishing’ Threat

The Federal Bureau of Investigation (FBI) and the Cybersecurity and Infrastructure Security Agency (CISA) on Thursday issued a joint alert to warn about the growing threat from voice phishing or “vishing” attacks targeting companies. The advisory came less than 24 hours after KrebsOnSecurity published an in-depth look at a crime group offering a service that people can hire to steal VPN credentials and other sensitive data from employees working remotely during the Coronavirus pandemic.

“The COVID-19 pandemic has resulted in a mass shift to working from home, resulting in increased use of corporate virtual private networks (VPNs) and elimination of in-person verification,” the alert reads. “In mid-July 2020, cybercriminals started a vishing campaign—gaining access to employee tools at multiple companies with indiscriminate targeting — with the end goal of monetizing the access.”

As noted in Wednesday’s story, the agencies said the phishing sites set up by the attackers tend to include hyphens, the target company’s name, and certain words — such as “support,” “ticket,” and “employee.” The perpetrators focus on social engineering new hires at the targeted company, and impersonate staff at the target company’s IT helpdesk.

The joint FBI/CISA alert (PDF) says the vishing gang also compiles dossiers on employees at the specific companies using mass scraping of public profiles on social media platforms, recruiter and marketing tools, publicly available background check services, and open-source research. From the alert:

“Actors first began using unattributed Voice over Internet Protocol (VoIP) numbers to call targeted employees on their personal cellphones, and later began incorporating spoofed numbers of other offices and employees in the victim company. The actors used social engineering techniques and, in some cases, posed as members of the victim company’s IT help desk, using their knowledge of the employee’s personally identifiable information—including name, position, duration at company, and home address—to gain the trust of the targeted employee.”

“The actors then convinced the targeted employee that a new VPN link would be sent and required their login, including any 2FA [2-factor authentication] or OTP [one-time passwords]. The actor logged the information provided by the employee and used it in real-time to gain access to corporate tools using the employee’s account.”

The alert notes that in some cases the unsuspecting employees approved the 2FA or OTP prompt, either accidentally or believing it was the result of the earlier access granted to the help desk impersonator. In other cases, the attackers were able to intercept the one-time codes by targeting the employee with SIM swapping, which involves social engineering people at mobile phone companies into giving them control of the target’s phone number. Continue reading →


19
Aug 20

Voice Phishers Targeting Corporate VPNs

The COVID-19 epidemic has brought a wave of email phishing attacks that try to trick work-at-home employees into giving away credentials needed to remotely access their employers’ networks. But one increasingly brazen group of crooks is taking your standard phishing attack to the next level, marketing a voice phishing service that uses a combination of one-on-one phone calls and custom phishing sites to steal VPN credentials from employees.

According to interviews with several sources, this hybrid phishing gang has a remarkably high success rate, and operates primarily through paid requests or “bounties,” where customers seeking access to specific companies or accounts can hire them to target employees working remotely at home.

And over the past six months, the criminals responsible have created dozens if not hundreds of phishing pages targeting some of the world’s biggest corporations. For now at least, they appear to be focusing primarily on companies in the financial, telecommunications and social media industries.

“For a number of reasons, this kind of attack is really effective,” said Allison Nixon, chief research officer at New York-based cyber investigations firm Unit 221B. “Because of the Coronavirus, we have all these major corporations that previously had entire warehouses full of people who are now working remotely. As a result the attack surface has just exploded.”

TARGET: NEW HIRES

A typical engagement begins with a series of phone calls to employees working remotely at a targeted organization. The phishers will explain that they’re calling from the employer’s IT department to help troubleshoot issues with the company’s virtual private networking (VPN) technology.

The employee phishing page bofaticket[.]com. Image: urlscan.io

The goal is to convince the target either to divulge their credentials over the phone or to input them manually at a website set up by the attackers that mimics the organization’s corporate email or VPN portal.

Zack Allen is director of threat intelligence for ZeroFOX, a Baltimore-based company that helps customers detect and respond to risks found on social media and other digital channels. Allen has been working with Nixon and several dozen other researchers from various security firms to monitor the activities of this prolific phishing gang in a bid to disrupt their operations.

Allen said the attackers tend to focus on phishing new hires at targeted companies, and will often pose as new employees themselves working in the company’s IT division. To make that claim more believable, the phishers will create LinkedIn profiles and seek to connect those profiles with other employees from that same organization to support the illusion that the phony profile actually belongs to someone inside the targeted firm.

“They’ll say ‘Hey, I’m new to the company, but you can check me out on LinkedIn’ or Microsoft Teams or Slack, or whatever platform the company uses for internal communications,” Allen said. “There tends to be a lot of pretext in these conversations around the communications and work-from-home applications that companies are using. But eventually, they tell the employee they have to fix their VPN and can they please log into this website.”

SPEAR VISHING

The domains used for these pages often invoke the company’s name, followed or preceded by hyphenated terms such as “vpn,” “ticket,” “employee,” or “portal.” The phishing sites also may include working links to the organization’s other internal online resources to make the scheme seem more believable if a target starts hovering over links on the page.

Allen said a typical voice phishing or “vishing” attack by this group involves at least two perpetrators: One who is social engineering the target over the phone, and another co-conspirator who takes any credentials entered at the phishing page and quickly uses them to log in to the target company’s VPN platform in real-time.

Time is of the essence in these attacks because many companies that rely on VPNs for remote employee access also require employees to supply some type of multi-factor authentication in addition to a username and password — such as a one-time numeric code generated by a mobile app or text message. And in many cases, those codes are only good for a short duration — often measured in seconds or minutes.

But these vishers can easily sidestep that layer of protection, because their phishing pages simply request the one-time code as well.

A phishing page (helpdesk-att[.]com) targeting AT&T employees. Image: urlscan.io

Allen said it matters little to the attackers if the first few social engineering attempts fail. Most targeted employees are working from home or can be reached on a mobile device. If at first the attackers don’t succeed, they simply try again with a different employee.

And with each passing attempt, the phishers can glean important details from employees about the target’s operations, such as company-specific lingo used to describe its various online assets, or its corporate hierarchy.

Thus, each unsuccessful attempt actually teaches the fraudsters how to refine their social engineering approach with the next mark within the targeted organization, Nixon said.

“These guys are calling companies over and over, trying to learn how the corporation works from the inside,” she said. Continue reading →


11
Aug 20

Microsoft Patch Tuesday, August 2020 Edition

Microsoft today released updates to plug at least 120 security holes in its Windows operating systems and supported software, including two newly discovered vulnerabilities that are actively being exploited. Yes, good people of the Windows world, it’s time once again to backup and patch up!

At least 17 of the bugs squashed in August’s patch batch address vulnerabilities Microsoft rates as “critical,” meaning they can be exploited by miscreants or malware to gain complete, remote control over an affected system with little or no help from users. This is the sixth month in a row Microsoft has shipped fixes for more than 100 flaws in its products.

The most concerning of these appears to be CVE-2020-1380, which is a weaknesses in Internet Explorer that could result in system compromise just by browsing with IE to a hacked or malicious website. Microsoft’s advisory says this flaw is currently being exploited in active attacks.

The other flaw enjoying active exploitation is CVE-2020-1464, which is a “spoofing” bug in virtually all supported versions of Windows that allows an attacker to bypass Windows security features and load improperly signed files. For more on this flaw, see Microsoft Put Off Fixing Zero for 2 Years.

Trend Micro’s Zero Day Initiative points to another fix — CVE-2020-1472 — which involves a critical issue in Windows Server versions that could let an unauthenticated attacker gain administrative access to a Windows domain controller and run an application of their choosing. A domain controller is a server that responds to security authentication requests in a Windows environment, and a compromised domain controller can give attackers the keys to the kingdom inside a corporate network.

“It’s rare to see a Critical-rated elevation of privilege bug, but this one deserves it,” said ZDI’S Dustin Childs. “What’s worse is that there is not a full fix available.”

Perhaps the most “elite” vulnerability addressed this month earned the distinction of being named CVE-2020-1337, and refers to a security hole in the Windows Print Spooler service that could allow an attacker or malware to escalate their privileges on a system if they were already logged on as a regular (non-administrator) user.

Satnam Narang at Tenable notes that CVE-2020-1337 is a patch bypass for CVE-2020-1048, another Windows Print Spooler vulnerability that was patched in May 2020. Narang said researchers found that the patch for CVE-2020-1048 was incomplete and presented their findings for CVE-2020-1337 at the Black Hat security conference earlier this month. More information on CVE-2020-1337, including a video demonstration of a proof-of-concept exploit, is available here. Continue reading →


30
Jul 20

Is Your Chip Card Secure? Much Depends on Where You Bank

Chip-based credit and debit cards are designed to make it infeasible for skimming devices or malware to clone your card when you pay for something by dipping the chip instead of swiping the stripe. But a recent series of malware attacks on U.S.-based merchants suggest thieves are exploiting weaknesses in how certain financial institutions have implemented the technology to sidestep key chip card security features and effectively create usable, counterfeit cards.

A chip-based credit card. Image: Wikipedia.

Traditional payment cards encode cardholder account data in plain text on a magnetic stripe, which can be read and recorded by skimming devices or malicious software surreptitiously installed in payment terminals. That data can then be encoded onto anything else with a magnetic stripe and used to place fraudulent transactions.

Newer, chip-based cards employ a technology known as EMV that encrypts the account data stored in the chip. The technology causes a unique encryption key — referred to as a token or “cryptogram” — to be generated each time the chip card interacts with a chip-capable payment terminal.

Virtually all chip-based cards still have much of the same data that’s stored in the chip encoded on a magnetic stripe on the back of the card. This is largely for reasons of backward compatibility since many merchants — particularly those in the United States — still have not fully implemented chip card readers. This dual functionality also allows cardholders to swipe the stripe if for some reason the card’s chip or a merchant’s EMV-enabled terminal has malfunctioned.

But there are important differences between the cardholder data stored on EMV chips versus magnetic stripes. One of those is a component in the chip known as an integrated circuit card verification value or “iCVV” for short — also known as a “dynamic CVV.”

The iCVV differs from the card verification value (CVV) stored on the physical magnetic stripe, and protects against the copying of magnetic-stripe data from the chip and the use of that data to create counterfeit magnetic stripe cards. Both the iCVV and CVV values are unrelated to the three-digit security code that is visibly printed on the back of a card, which is used mainly for e-commerce transactions or for card verification over the phone.

The appeal of the EMV approach is that even if a skimmer or malware manages to intercept the transaction information when a chip card is dipped, the data is only valid for that one transaction and should not allow thieves to conduct fraudulent payments with it going forward.

However, for EMV’s security protections to work, the back-end systems deployed by card-issuing financial institutions are supposed to check that when a chip card is dipped into a chip reader, only the iCVV is presented; and conversely, that only the CVV is presented when the card is swiped. If somehow these do not align for a given transaction type, the financial institution is supposed to decline the transaction.

The trouble is that not all financial institutions have properly set up their systems this way. Unsurprisingly, thieves have known about this weakness for years. In 2017, I wrote about the increasing prevalence of “shimmers,” high-tech card skimming devices made to intercept data from chip card transactions.

A close-up of a shimmer found on a Canadian ATM. Source: RCMP.

More recently, researchers at Cyber R&D Labs published a paper detailing how they tested 11 chip card implementations from 10 different banks in Europe and the U.S. The researchers found they could harvest data from four of them and create cloned magnetic stripe cards that were successfully used to place transactions.

There are now strong indications the same method detailed by Cyber R&D Labs is being used by point-of-sale (POS) malware to capture EMV transaction data that can then be resold and used to fabricate magnetic stripe copies of chip-based cards.

Earlier this month, the world’s largest payment card network Visa released a security alert regarding a recent merchant compromise in which known POS malware families were apparently modified to target EMV chip-enabled POS terminals.

“The implementation of secure acceptance technology, such as EMV® Chip, significantly reduced the usability of the payment account data by threat actors as the available data only included personal account number (PAN), integrated circuit card verification value (iCVV) and expiration date,” Visa wrote. “Thus, provided iCVV is validated properly, the risk of counterfeit fraud was minimal. Additionally, many of the merchant locations employed point-to-point encryption (P2PE) which encrypted the PAN data and further reduced the risk to the payment accounts processed as EMV® Chip.”

Visa did not name the merchant in question, but something similar seems to have happened at Key Food Stores Co-Operative Inc., a supermarket chain in the northeastern United States. Key Food initially disclosed a card breach in March 2020, but two weeks ago updated its advisory to clarify that EMV transaction data also was intercepted.

“The POS devices at the store locations involved were EMV enabled,” Key Food explained. “For EMV transactions at these locations, we believe only the card number and expiration date would have been found by the malware (but not the cardholder name or internal verification code).”

While Key Food’s statement may be technically accurate, it glosses over the reality that the stolen EMV data could still be used by fraudsters to create magnetic stripe versions of EMV cards presented at the compromised store registers in cases where the card-issuing bank hadn’t implemented EMV correctly. Continue reading →


19
Jun 20

Turn on MFA Before Crooks Do It For You

Hundreds of popular websites now offer some form of multi-factor authentication (MFA), which can help users safeguard access to accounts when their password is breached or stolen. But people who don’t take advantage of these added safeguards may find it far more difficult to regain access when their account gets hacked, because increasingly thieves will enable multi-factor options and tie the account to a device they control. Here’s the story of one such incident.

As a career chief privacy officer for different organizations, Dennis Dayman has tried to instill in his twin boys the importance of securing their online identities against account takeovers. Both are avid gamers on Microsoft’s Xbox platform, and for years their father managed their accounts via his own Microsoft account. But when the boys turned 18, they converted their child accounts to adult, effectively taking themselves out from under their dad’s control.

On a recent morning, one of Dayman’s sons found he could no longer access his Xbox account. The younger Dayman admitted to his dad that he’d reused his Xbox profile password elsewhere, and that he hadn’t enabled multi-factor authentication for the account.

When the two of them sat down to reset his password, the screen displayed a notice saying there was a new Gmail address tied to his Xbox account. When they went to turn on multi-factor authentication for his son’s Xbox profile — which was tied to a non-Microsoft email address — the Xbox service said it would send a notification of the change to unauthorized Gmail account in his profile.

Wary of alerting the hackers that they were wise to their intrusion, Dennis tried contacting Microsoft Xbox support, but found he couldn’t open a support ticket from a non-Microsoft account. Using his other son’s Outlook account, he filed a ticket about the incident with Microsoft.

Dennis soon learned the unauthorized Gmail address added to his son’s hacked Xbox account also had enabled MFA. Meaning, his son would be unable to reset the account’s password without approval from the person in control of the Gmail account.

Luckily for Dayman’s son, he hadn’t re-used the same password for the email address tied to his Xbox profile. Nevertheless, the thieves began abusing their access to purchase games on Xbox and third-party sites.

“During this period, we started realizing that his bank account was being drawn down through purchases of games from Xbox and [Electronic Arts],” Dayman the elder recalled. “I pulled the recovery codes for his Xbox account out of the safe, but because the hacker came in and turned on multi-factor, those codes were useless to us.”

Microsoft support sent Dayman and his son a list of 20 questions to answer about their account, such as the serial number on the Xbox console originally tied to the account when it was created. But despite answering all of those questions successfully, Microsoft refused to let them reset the password, Dayman said.

“They said their policy was not to turn over accounts to someone who couldn’t provide the second factor,” he said.

Dayman’s case was eventually escalated to Tier 3 Support at Microsoft, which was able to walk him through creating a new Microsoft account, enabling MFA on it, and then migrating his son’s Xbox profile over to the new account.

Microsoft told KrebsOnSecurity that while users currently are not prompted to enable two-step verification upon sign-up, they always have the option to enable the feature.

“Users are also prompted shortly after account creation to add additional security information if they have not yet done so, which enables the customer to receive security alerts and security promotions when they login to their account,” the company said in a written statement. “When we notice an unusual sign-in attempt from a new location or device, we help protect the account by challenging the login and send the user a notification. If a customer’s account is ever compromised, we will take the necessary steps to help them recover the account.” Continue reading →


14
Jun 20

Privnotes.com Is Phishing Bitcoin from Users of Private Messaging Service Privnote.com

For the past year, a site called Privnotes.com has been impersonating Privnote.com, a legitimate, free service that offers private, encrypted messages which self-destruct automatically after they are read. Until recently, I couldn’t quite work out what Privnotes was up to, but today it became crystal clear: Any messages containing bitcoin addresses will be automatically altered to include a different bitcoin address, as long as the Internet addresses of the sender and receiver of the message are not the same.

Earlier this year, KrebsOnSecurity heard from the owners of Privnote.com, who complained that someone had set up a fake clone of their site that was fooling quite a few regular users of the service.

And it’s not hard to see why: Privnotes.com is confusingly similar in name and appearance to the real thing, and comes up second in Google search results for the term “privnote.” Also, anyone who mistakenly types “privnotes” into Google search may see at the top of the results a misleading paid ad for “Privnote” that actually leads to privnotes.com.

A Google search for the term “privnotes” brings up a misleading paid ad for the phishing site privnotes.com, which is listed above the legitimate site — privnote.com.

Privnote.com (the legit service) employs technology that encrypts all messages so that even Privnote itself cannot read the contents of the message. And it doesn’t send and receive messages. Creating a message merely generates a link. When that link is clicked or visited, the service warns that the message will be gone forever after it is read.

But according to the owners of Privnote.com, the phishing site Privnotes.com does not fully implement encryption, and can read and/or modify all messages sent by users.

“It is very simple to check that the note in privnoteS is sent unencrypted in plain text,” Privnote.com explained in a February 2020 message, responding to inquiries from KrebsOnSecurity. “Moreover, it doesn’t enforce any kind of decryption key when opening a note and the key after # in the URL can be replaced by arbitrary characters and the note will still open.”

But that’s not the half of it. KrebsOnSecurity has learned that the phishing site Privnotes.com uses some kind of automated script that scours messages for bitcoin addresses, and replaces any bitcoin addresses found with its own bitcoin address. The script apparently only modifies messages if the note is opened from a different Internet address than the one that composed the address.

Here’s an example, using the bitcoin wallet address from bitcoin’s Wikipedia page as an example. The following message was composed at Privnotes.com from a computer with an Internet address in New York, with the message, “please send money to bc1qar0srrr7xfkvy5l643lydnw9re59gtzzwf5mdq thanks”:

A test message composed on privnotes.com, which is phishing users of the legitimate encrypted message service privnote.com. Pay special attention to the bitcoin address in this message.

When I visited the Privnotes.com link generated by clicking the “create note” button on the above page from a different computer with an Internet address in California, this was the result. As you can see, it lists a different bitcoin address, albeit one with the same first four characters.

The altered message. Notice the bitcoin address has been modified and is not the same address that was sent in the original note.

Several other tests confirmed that the bitcoin modifying script does not seem to change message contents if the sender and receiver’s IP addresses are the same, or if one composes multiple notes with the same bitcoin address in it. Continue reading →


9
Jun 20

Florence, Ala. Hit By Ransomware 12 Days After Being Alerted by KrebsOnSecurity

In late May, KrebsOnSecurity alerted numerous officials in Florence, Ala. that their information technology systems had been infiltrated by hackers who specialize in deploying ransomware. Nevertheless, on Friday, June 5, the intruders sprang their attack, deploying ransomware and demanding nearly $300,000 worth of bitcoin. City officials now say they plan to pay the ransom demand, in hopes of keeping the personal data of their citizens off of the Internet.

Nestled in the northwest corner of Alabama, Florence is home to roughly 40,000 residents. It is part of a quad-city metropolitan area perhaps best known for the Muscle Shoals Sound Studio that recorded the dulcet tones of many big-name music acts in the 1960s and 70s.

Image: Florenceal.org

On May 26, acting on a tip from Milwaukee, Wisc.-based cybersecurity firm Hold Security, KrebsOnSecurity contacted the office of Florence’s mayor to alert them that a Windows 10 system in their IT environment had been commandeered by a ransomware gang.

Comparing the information shared by Hold Security dark web specialist Yuliana Bellini with the employee directory on the Florence website indicated the username for the computer that attackers had used to gain a foothold in the network on May 6 belonged to the city’s manager of information systems.

My call was transferred to no fewer than three different people, none of whom seemed eager to act on the information. Eventually, I was routed to the non-emergency line for the Florence police department. When that call went straight to voicemail, I left a message and called the city’s emergency response team.

That last effort prompted a gracious return call the following day from a system administrator for the city, who thanked me for the heads up and said he and his colleagues had isolated the computer and Windows network account Hold Security flagged as hacked.

“I can’t tell you how grateful we are that you helped us dodge this bullet,” the technician said in a voicemail message for this author. “We got everything taken care of now, and some different protocols are in place. Hopefully we won’t have another near scare like we did, and hopefully we won’t have to talk to each other again.”

But on Friday, Florence Mayor Steve Holt confirmed that a cyberattack had shut down the city’s email system. Holt told local news outlets at the time there wasn’t any indication that ransomware was involved.

However, in an interview with KrebsOnSecurity Tuesday, Holt acknowledged the city was being extorted by DoppelPaymer, a ransomware gang with a reputation for negotiating some of the highest extortion payments across dozens of known ransomware families.

The average ransomware payment by ransomware strain. Source: Chainalysis.

Holt said the same gang appears to have simultaneously compromised networks belonging to four other victims within an hour of Florence, including another municipality that he declined to name. Holt said the extortionists initially demanded 39 bitcoin (~USD $378,000), but that an outside security firm hired by the city had negotiated the price down to 30 bitcoin (~USD $291,000).

Like many other cybercrime gangs operating these days, DoppelPaymer will steal reams of data from victims prior to launching the ransomware, and then threaten to publish or sell the data unless a ransom demand is paid.

Holt told KrebsOnSecurity the city can’t afford to see its citizens’ personal and financial data jeopardized by not paying.

“Do they have our stuff? We don’t know, but that’s the roll of the dice,” Holt said. Continue reading →