Category: Naked Security

Feb 21 2018

Intel ships (hopefully stable) microcode for Skylake, Kaby Lake, Coffee Lake

Enlarge / Intel Core i9 X-series Skylake X. (credit: Intel)

Intel reports that it has developed a stable microcode update to address the Spectre flaw for its Skylake, Kaby Lake, and Coffee Lake processors in all their various variants.

The microcode updates help address Spectre variant 2 attacks. Spectre variant 2 attacks work by persuading a processor's branch predictor to make a specific bad prediction about which code will be executed. This bad prediction can then be used to infer the value of data stored in memory, which, in turn, gives an attacker information that they shouldn't otherwise have. The microcode update is designed to give operating systems greater control over the branch predictor, enabling them to prevent one process from influencing the predictions made in another process.

Intel's first microcode update, developed late last year, was included in system firmware updates for machines with Broadwell, Haswell, Skylake, Kaby Lake, and Coffee Lake processors. But users subsequently discovered that the update was causing systems to crash and reboot. Initially, only Broadwell and Haswell systems were confirmed to be affected, but further examination determined that Skylake, Kaby Lake, and Coffee Lake systems were rebooting, too.

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Feb 19 2018

Krebs on Security 2018-02-19 10:44:49

Identity thieves who specialize in tax refund fraud have been busy of late hacking online accounts at multiple tax preparation firms, using them to file phony refund requests. Once the Internal Revenue Service processes the return and deposits money into bank accounts of the hacked firms’ clients, the crooks contact those clients posing as a collection agency and demand that the money be “returned.”

In one version of the scam, criminals are pretending to be debt collection agency officials acting on behalf of the IRS. They’ll call taxpayers who’ve had fraudulent tax refunds deposited into their bank accounts, claim the refund was deposited in error, and threaten recipients with criminal charges if they fail to forward the money to the collection agency.

This is exactly what happened to a number of customers at a half dozen banks in Oklahoma earlier this month. Elaine Dodd, executive vice president of the fraud division at the Oklahoma Bankers Association, said many financial institutions in the Oklahoma City area had “a good number of customers” who had large sums deposited into their bank accounts at the same time.

Dodd said the bank customers received hefty deposits into their accounts from the U.S. Treasury, and shortly thereafter were contacted by phone by someone claiming to be a collections agent for a firm calling itself DebtCredit and using the Web site name debtcredit[dot]us.

“We’re having customers getting refunds they have not applied for,” Dodd said, noting that the transfers were traced back to a local tax preparer who’d apparently gotten phished or hacked. Those banks are now working with affected customers to close the accounts and open new ones, Dodd said. “If the crooks have breached a tax preparer and can send money to the client, they can sure enough pull money out of those accounts, too.”

Several of the Oklahoma bank’s clients received customized notices from a phony company claiming to be a collections agency hired by the IRS.

The domain debtcredit[dot]us hasn’t been active for some time, but an exact copy of the site to which the bank’s clients were referred by the phony collection agency can be found at jcdebt[dot]com — a domain that was registered less than a month ago. The site purports to be associated with a company in New Jersey called Debt & Credit Consulting Services, but according to a record (PDF) retrieved from the New Jersey Secretary of State’s office, that company’s business license was revoked in 2010.

“You may be puzzled by an erroneous payment from the Internal Revenue Service but in fact it is quite an ordinary situation,” reads the HTML page shared with people who received the fraudulent IRS refunds. It includes a video explaining the matter, and references a case number, the amount and date of the transaction, and provides a list of personal “data reported by the IRS,” including the recipient’s name, Social Security Number (SSN), address, bank name, bank routing number and account number.

All of these details no doubt are included to make the scheme look official; most recipients will never suspect that they received the bank transfer because their accounting firm got hacked.

The scammers even supposedly assign the recipients an individual “appointed debt collector,” complete with a picture of the employee, her name, telephone number and email address. However, the emails to the domain used in the email address from the screenshot above (debtcredit[dot]com) bounced, and no one answers at the provided telephone number.

Along with the Web page listing the recipient’s personal and bank account information, each recipient is given a “transaction error correction letter” with IRS letterhead (see image below) that includes many of the same personal and financial details on the HTML page. It also gives the recipient instructions on the account number, ACH routing and wire number to which the wayward funds are to be wired.

A phony letter from the IRS instructing recipients on how and where to wire the money that was deposited into their bank account as a result of a fraudulent tax refund request filed in their name.

Tax refund fraud affects hundreds of thousands, if not millions, of U.S. citizens annually. Victims usually first learn of the crime after having their returns rejected because scammers beat them to it. Even those who are not required to file a return can be victims of refund fraud, as can those who are not actually due a refund from the IRS.

On Feb. 2, 2018, the IRS issued a warning to tax preparers, urging them to step up their security in light of increased attacks. On Feb. 13, the IRS warned that phony refunds through hacked tax preparation accounts are a “quickly growing scam.”

“Thieves know it is more difficult to identify and halt fraudulent tax returns when they are using real client data such as income, dependents, credits and deductions,” the agency noted in the Feb. 2 alert. “Generally, criminals find alternative ways to get the fraudulent refunds delivered to themselves rather than the real taxpayers.”

The IRS says taxpayer who receive fraudulent transfers from the IRS should contact their financial institution, as the account may need to be closed (because the account details are clearly in the hands of cybercriminals). Taxpayers receiving erroneous refunds also should consider contacting their tax preparers immediately.

If you go to file your taxes electronically this year and the return is rejected, it may mean fraudsters have beat you to it. The IRS advises taxpayers in this situation to follow the steps outlined in the Taxpayer Guide to Identity Theft. Those unable to file electronically should mail a paper tax return along with Form 14039 (PDF) — the Identity Theft Affidavit — stating they were victims of a tax preparer data breach.

Feb 16 2018

32 class-action suits filed against Intel over Spectre and Meltdown flaws

Enlarge / This may become the new default imagery for Spectre and Meltdown around Intel. (credit: Brian Turner / Flickr)

In its annual SEC filing, Intel has revealed that it's facing 32 lawsuits over the Spectre and Meltdown attacks on its processors. While the Spectre problem is a near-universal issue faced by modern processors, the Meltdown attack is specific to processors from Intel and Apple, along with certain ARM designs that are coming to market shortly.

Per Intel's filing, 30 of the cases are customer class-action suits from users claiming to be harmed by the flaws. While Meltdown has effective workarounds, they come with some performance cost. Workarounds for Spectre are more difficult and similarly can harm system performance.

The other two cases are securities class actions that claim that Intel made misleading public statements during the six-month period after the company was notified of the problems but before the attacks were made public.

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Feb 16 2018

Free Ransomware Available on Dark Web

The McAfee Advanced Threat Research team recently analyzed a ransomware-as-a-service threat that is available for free and without registration. This malware was first seen in July 2017 with the extension .shifr. It has now appeared in recent detections with the extension .cypher.

Ransomware-as-a-Service

Ransomware-as-a-service is a cybercrime economic model that allows malware developers to earn money for their creations without the need to distribute their threats. Nontechnical criminals buy their wares and launch the infections, while paying the developers a percentage of their take. The developers run relatively few risks, and their customers do most of the work.

Some ransomware-as-a-service, such as RaaSberry, use subscriptions while others require registration to gain access to the ransomware. The ransomware developer hosts a service on the “dark web” that allows any buyer to create and modify the malware. For example, the buyer can add custom ransom notes and the amount of the payment. More advanced services offer features such as evasion techniques to avoid detection and analysis. The service can also offer a control server with an administration panel to manage each victim. This system is convenient for both the developer, who makes money by selling malware, and for buyers, who gain ready-to-deploy ransomware without needing any specific coding knowledge.

The underground economy behind this service is well organized, effectively offering a cybercrime infrastructure. Basically, the ransomware is available on a website. The buyer sets up the ransomware by adding a wallet address. The ransomware is then available to download. The buyer just needs to customize and spread the malware. When a victim pays the ransom, a percentage is delivered both to the buyer and to the malware coder.

 

The ransomware is available on the TOR network at hxxp://kdvm5fd6tn6jsbwh.onion. A web page guides buyers through the configuration process.

On the configuration page, a generic XMPP address suggests we may have found a demo version of the ransomware.

On the page, the buyer need only to add a Bitcoin wallet address and the amount of the ransom. Once that is done, the malware is generated and can be downloaded. With this malware, the developer earns a 10% commission on every payment. Now let’s look at the malware sample.

Dynamic Analysis 

When the malware launches on the victim’s system, it checks for an Internet connection. If there is none, it exits the process. Otherwise, it contacts the following addresses to download the encryption key:

Once the file is running, it creates several files on the system:

  • Encryption_key: the RSA key encrypted in AES
  • Lock_file: an indicator that the system is encrypted
  • Uuid_file: a reference for the infected machine. A TOR address is generated with this ID.

The encryption key is downloaded from hxxps://kdvm5fd6tn6jsbwh.onion.to/new_c/xmKksHw53W433lmvNsdzGxqWLcPLA44Dyna.

The ransom note is created on the desktop.

The file “HOW_TO_DECRYPT_FILES.html” gives a link to the TOR network.

Once the files are encrypted, the ransom note is displayed in HTML and points to the TOR site hxxp://kdvm5fd6tn6jsbwh.onion/ with the ID of the infected machine.

Allegedly after payment, the victim can download the file decrypter.exe and unlock encrypted files, which have the extension .cypher.

The malware encrypts the following file extensions:

The targeted extensions include many picture and photography files related to Canon, Kodak, Sony, and others. There are also extensions for AutoCAD, Autodesk projects, scalable vector images, and Microsoft Office files. These files are mostly used by designers, photographers, architect—and many others.

Digging Deeper

The malware runs on 64-bit systems and is coded in Golang (“Go language,” from Google), a programming language similar to C with some improvements in error management. It is not common to find malware using Golang, although this is not the first time that we have analyzed such malware. This threat is pretty big compared with most other malware, larger than 5.5MB. The file size can make analysis more difficult and can also help evade hardcoded antimalware file-inspection sizes.

Reverse engineering in Golang is a bit different than other languages. Golang binaries are usually bigger than other executables. (By default, the compiler statically links the program’s libraries, resulting a bigger file.)

A drawback for attackers is that such big binaries can be easily detected on a corporate network. Large files are “noisier” and may appear suspicious when arriving from an external source. They can also be less convenient for attackers to deal with because they can make the infection process more difficult.

The first interesting function to analyze in a Golang binary is the “main_main.” The malware starts by gathering environment variables. It then checks whether the file “lock_file” exists in the directory C:\Users\<username>\AppData\Roaming.

The function “main_Exists” will check for the file. If it does not exist, the malware exits the process.

If the file does exist, the malware downloads the public key from the control server.

The malware contacts the address  hxxps://kdvm5fd6tn6jsbwh.onion/new_c/<nameofmalware>. The encryption public key is stored directly on the website.

This address is generated when the buyer creates the ransomware on the developer’s web page; thus the same malware encrypts files with the same public key.

The malware generates the AES key and tries to find any network share by querying the letters.

This function tries to find network shares:

Before a file is encrypted, the malware creates another file in C:\Users\<username>\AppData\Roaming\uuid_file to use as a victim identifier.

The malware encrypts the files using AES and deletes them after encryption with the function “os.remove” to avoid any simple forensic recovery.

The decrypter, which can be downloaded, works in a similar way but it requests the private key that the victims must pay for at hxxps://kdvm5fd6tn6jsbwh.onion.to/get_privkey/math/big. The mechanism behind the encryption routine seems to be on the online server and the decryption key cannot be easily recovered.

The following information describes the decrypter.

Conclusion

Cybercrime-as-a-service is not new, yet it is now more widespread than ever. In this case, the malware is available for free but the ransomware developer earns a 10% fee from each victim who pays a ransom. The use of Golang is not common for malware. Most ransomware-as-a-service is not free, which could indicate this might be a demonstration version, or a proof of concept for future sale.

This malware is not advanced and was coded without evasion techniques, such as DGA, SSL for control, encryption, or even file compression. Looking at the targeted file extensions suggests the victims can range from general home or business users to the graphics industry. Although such malware is not difficult to analyze, it can be very destructive in a corporate environment.

Keep in mind that paying a ransom is no guarantee of receiving a decryption key. McAfee advises that you never pay a ransom. You can find further information and help on unlocking some ransomware threats at https://www.nomoreransom.org.

McAfee detects this threat as Ransomware-FPDS!0F8CCEE515B8.

 

Indicators of Compromise

Hashes:

  • cb73927aa749f88134ab7874b15df898c014a35d519469f59b1c85d32fa69357
  • 0622fcb172773d8939b451c43902095b0f91877ae05e562c60d0ca0c237a2e9c

IP address:

  • hxxp://kdvm5fd6tn6jsbwh.onion

Files created:

  • C:\Users\<username>\AppData\Roaming\uuid_file
  • C:\Users\<username>\AppData\Roaming\lock_file
  • C:\Users\<username>\AppData\Roaming\encryption_key
  • C:\Users\< username >\Desktop\HOW_TO_DECRYPT_FILES.html

Encryption extension:

  • .cypher

References:

https://www.virustotal.com/en/file/0622fcb172773d8939b451c43902095b0f91877ae05e562c60d0ca0c237a2e9c/analysis/

https://isc.sans.edu/forums/diary/Ransomware+as+a+Service/23277/

 

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