Security Reports

Global Security Report - End of Year 2018


EXECUTIVE SUMMARY

The AppRiver Global Security Report for 2018 highlights the threats and trends AppRiver Security analysts saw throughout the year.

In 2018, analysts saw banking Trojans gain in popularity, while ransomware usage dipped and became more of a secondary tactic. AppRiver analysts also noted that attackers sent less malware through attachments in favor of sending malicious payloads via infected URLS. Spearphishing attacks remained popular – leveraging lots of new twists on recent attack vectors.

In this report, we will take a deep dive into many of the threats and trends we saw in email security as well as discuss examples of prevalent attacks and explore potential impacts.

INTRODUCTION

In 2018, threat actors’ tactics, traits and techniques continued to morph while security solutions proved they had to be agile enough to evolve and respond just as quickly.

While 2017 was defined by ransomware running rampant and large data breaches, we saw a shift to new, yet familiar tactics, being embraced by the adversary on a wide scale.

In 2018 banking trojans (info stealers) were being distributed at a fever pitch, superseding ransomware. And while malware delivered as an email attachment saw a slight decline, the means of distributing malicious payloads via infected URLs more than made up for the attachment decrease.

Spearphishing attacks such as Business Email Compromises (BECs) continued to turn up the heat in 2018 as they leveraged lots of new twists on recent attack vectors as well as launching attacks from further embedded positions.

Large data breaches continued to dominate 2018 headlines on a nearly daily basis. By the end of the year, most everyone that wasn’t already suffering from a serious case of breach-fatigue was by the time January 2019 rolled around.

In this report, we will take a deep dive into many of these and other trends in email security. We will also discuss examples of prevalent attacks and explore potential impacts.

BANKING/INFO-STEALER TROJANS ON THE RISE, CONTINUALLY EVOLVING

Banking trojans have seen somewhat of a renaissance in 2018. Over the course of the year, banking trojans became the most commonly distributed threat type. Though some new ransomware threats such as GandCrab emerged in 2018, the banking malware families dominated the email-threat landscape.

While the ransomware technique has proven to be a very viable cyberattack technique, the attack pendulum has swung from the in-your-face attacks that force victims to pay a ransom to siphoning funds completely under the radar. Many of these malware types are threats that have been around before 2018 but as their use has continued to grow so has their functionality and capabilities.

Unlike ransomware, this family of threats goes to great lengths to keep their infection invisible to the end user and the security measures. They operate stealthily, live off the land by taking advantage of native process, inject code directly into memory to avoid detection and transfer away funds without setting off alarms. Unlike with a Ransomware attack, the victim may not realize they are a victim until funds have been whisked away to some offshore account, most often never to return.

The majority of these banking trojans rely heavily on email as a crucial part of their infection chain.

The Trickbot Trojan has been consistently attempting to find its way into users’ inboxes throughout the year. Trickbot relies heavily on spoofed emails that are carefully crafted to look like legitimate email notifications from reputable financial institutions. The messages AppRiver filters captured were crafted to appear as legitimate “secure” emails from Lloyds Bank. The email requested the recipient to review attached documents, sign and fax back.

This approach is one we have seen before as the purveyors of Trickbot have often used Lloyds, HSBC, Barclays and NatWest themes in their malicious email campaigns. Trickbot distributors usually deliver their malware payload within a macro-enabled word or excel attachment.

Trickbot has received consistent upgrades over its lifecycle. It was seen leveraging the Eternal Blue exploit with MS17-010, thus giving it worm capabilities, not long after WannaCry had such success spreading via its use.

However, its primary functionality is to commit financial theft. Late last year, Trickbot was updated with modules to target cryptocurrency wallets such as Coinbase. It contains routines to disable Windows Defender and other AV, evade sandboxing, code-injection, key- logging, contact scraping and startup persistence. This evolution shows an effort on the part of the distributors to vary their business model to what works best to maximize their return per infection.

EMOTET

Another and even more prominent threat that we are seeing at an alarming rate is the Emotet banking Trojan. Emotet is another custom Banking Trojan that relies on heavy obfuscation and evasion techniques to go undetected while committing financial theft. Similar to Trickbot, Emotet spreads itself throughout the network by making use of its spreader module which uses brute force attacks within the network as well as leveraging the SMB worm vulnerability EternalBlue. US Cert has said that “Emotet infections have cost SLTT governments up to $1 million per incident to remediate.”

Emotet is a very fluid and evasive polymorphic Trojan loader. It was first spotted in the wild in 2014. Since then it has been continuously refined by the authors and has escalated to one of the largest players in the email-spread Malware threat landscape. It began as a Trojan loader for the group’s own nefarious purposes.

To avoid detection, indicators of compromise (IoCs) may change as quickly as every 10 minutes with payloads (file hashes) changing every couple of hours or in some cases, quicker. Emotet has morphed into a modular loader where different payload components may easily be utilized by the malicious actors. Some modules or dll’s currently or previously used include:

  • Enumerator and Worm Spreading Capability – enumerates other resources in the environment, attempts to brute-force admin and user account passwords, and spread laterally throughout the network via the SMB protocol.
  • NetPass.exe – a legitimate utility for administrators created by Nirsoft to recover network passwords stored on the system or external drives, mail passwords on Exchange, browser stored passwords (IE7.x & IE8.x), and Messenger passwords.
  • WebBrowserPassView – Nirsoft utility designed for recovery of passwords stored by the most common web browsers.
  • MailPassView – Nirsoft utility for the recovery of email passwords. This includes Outlook, Thunderbird, Windows Mail, Gmail, Hotmail and Yahoo Mail accounts.
  • Outlook scraping – harvests contacts from Outlook to use for attacks against address book contacts. Exploits the trust between sender and recipient for spreading further.

In addition to the modules listed above, Emotet also has been observed dropping the following secondary payloads post-infection:

  • Banking Trojans: IcedID, Trickbot, Qakbot, Gootkit, Zeus Panda and Dridex
  • Remote Access Trojans (RATs): Azorult
  • Ransomware: Bitpaymer, Ryuk and Umbrecrypt have been documented from the secondary payload infections, especially after Trickbot.

 

In addition to the modules, some of the latest updates to Emotet include the ability to extract up to 180 days of emails and history from an infected system. The infrastructure also has been upgraded to include dual independent server clusters. This allows for redundancy if one goes down.

From an incident response standpoint, Emotet’s aggressive spreading and persistence abilities make it an extremely difficult piece of malware to remove. There are reports, such as the city of Allentown, PA’s remediation, where the cost has exceeded a million dollars. In addition, secondary payloads such as Trickbot contain their own unique removal challenges. Remnants of some infections may remain in memory even if the malicious items on disk are removed.

Messages come in a variety of methods, some appear to be typical phishing message with a link to download a malicious Word document. Alternatively, we capture messages with directly attached malicious Word and PDF documents. Quite often these different attack methods run simultaneously. Emotet has been one of the most prolific pieces of malware that our email filters have caught this year with well over 20 million examples caught this year.

However, as the coding and sophistication became increasingly refined over time, so did the business model. As such, it has evolved to a distribution model for other threat actors to utilize while the Emotet authors take a cut of the profits. Historically speaking, it does appear there is little variance between follow-up (secondary) malware payloads. This could be interpreted as Emotet authors being very selective in who or what groups they allow to use their loader. The afore mentioned Trickbot happens to be one that we have observed using the Emotet downloader.

GOZI and the CHA

Another malware family that falls squarely into the “Banking Trojan” category is Gozi. We have seen this payload being distributed heavily throughout 2018.

The Gozi/Ursnif Trojan, whose source code has leaked several times over the years, has a rootkit component, it captures browser and email application passwords, logs keystrokes and captures screenshots. While this malware poses a great threat to the individuals being targeted, an even greater risk is for the business or organization whose network would be exposed if the attack is successful.

The primary vector of distribution for this attack has been in the form of Conversation Hijacking Attacks (CHAs). We have reported extensively on these attacks over the past several years. They are particularly concerning in that they are a highly effective means of social engineering and the accounts/machines being used to launch these attackers already are compromised.

A product of account takeovers, CHAs have been capitalizing on the trust established by two individuals that have had a prior conversation (You can read more here for a detailed look at how these attacks work.).

These attacks reached a fever pitch in late summer, peaking in September.

Better protection against banking Trojans

Although the aforementioned malware strains could easily be referred to as Spyware, however, the main focus of their activities is to commit financial theft against businesses and individuals’ bank accounts. A robust defense-in-depth approach is necessary to harden your business against these and the vast number of other malware threats that are constantly competing to finding their way onto your network.

DSD ARE PEAKING IN ACTIVITY

Distributed Spam Distraction attacks have been increasing over the past several years. This attack utilizes what is sometimes referred to an “email bomb” on the Dark Web, where it is available as a service to anyone willing to spend a few bucks to make an individual’s email inbox unusable at the drop of a hat.

DSD attacks are initiated by a web crawler that scours the web for legitimate but unsecured web forms and signs up a user for newsletters and free memberships in-masse. The target then receives a flood of “welcome” emails that make the inbox unusable for a period. This could be used with several different motivations in mind.

What differentiates the “DSD” from an “email bomb” is the motivation behind flooding the inbox. In a DSD attack the email flood is being leveraged is so that the attacker can hide a fraudulent purchase transaction email in the veritable haystack of noise created by this flood of “welcome” emails, essentially aiming to blindfold the victim to the theft being committed. Often these are purchases from an online retailer that are being shipped to what are very likely an unwitting participant’s address.

Unfortunately, there are no preventative measures that can be taken to prevent this attack. Aside from protecting your online accounts and passwords as you normally would. Another annoyance of the attack is that once launched, your email address is destined for a life of bulkmail servitude. Making sure that your email security provider provides a means to direct bulkmail to a dedicated folder is essential once this attack has been launched against you. If you think an attack like this is being levied against you, take immediate action to root out any fraudulent purchase activity and stop the transactions while there is still time.

BECs

While the high-tech Banking Trojans have become more advanced so have social engineering attacks. These attacks put the human employee directly in the crosshairs. Many of these which can be classified as Business Email Compromise (BECs) generally take a very low-tech approach but dial up the social engineering to dupe unsuspecting employees into financial loss. These attacks are being committed by an increasingly wide spectrum of at- tackers and vary in level of complexity. When these phishing attacks are successful it ends with the employee making a major blunder and willingly giving over company money to the bad guys. Don’t be that person!

Let’s get into the nuts and bolts of some of these type of attacks so you know how to identify them if you ever are hit with one.

HOW BECs WORK

Most of these attacks rely of deception as it relates to the identity of the sender. Most often they are spoofing the “display name” of the CEO and making financial requests. However, we also have seen many other variations where attackers are spoofing the identity of vendors or lower tier employees. Keep in mind that the “From” field in an email can say ANYTHING the sender wants it to.

EXAMINING THE ATTACKS

One example we saw had the attacker posing as the CEO. The message, which is requesting gift cards, is addressed to an employee in the Finance department.

This type of attack is very common, and the litany of reasons the gift cards are needed is endless. If the attacker can sink the hook with this one, they will in turn ask for images of these gift cards with PIN number exposed to be emailed to them which they can then use to make online purchases.

In another variant, the attacker spoofed the name of a lower-level employee in a message to the company Human Resources director. In this attack they are posing as the employee and asking that their payroll information be changed to a new account number. Of course, they plan on making away with the deposit amount once payday has arrived.

Another type of this attack had the attacker posing as the CEO or another high-ranking executive and requesting a wire transfer. These type of attacks are often the most damaging, with the average cost of this type of attack being $130,000.

Of course, there are all sorts of variations of this third version. Some are so involved that the attacker has breached the inbox of the target to conduct reconnaissance in advance. They study business dealings in depth and learn about relationships with vendors, who’s paying who and for what, which enables them to craft a spoofed message for a phony invoice that comes across so naturally that it far more likely to be treated as legitimate and paid. It is not unusual to hear of organizations that have suffered seven figure losses in these elaborate phishing attacks.

It is evident that the rise of professional networking sites such as LinkedIn have helped to fuel this trend by providing the attackers with a never-ending list of names and job titles to appropriately contextualize these phishing attacks. In fact, in virtually every deep dive we do with one of these attacks we find the message recipient is active on LinkedIn, except for a few cases where they were likely gathered from company press releases or websites. We have also observed a recent twist to the BEC. In some instances where the attacker is attempting to channel hop by sending a very vague email to the target with the request to “text them back” at a phone number provided. Since this immediately takes the email security out of the equation (by switching to SMS) this could be embraced more going forward.

AN ATTACKER’S INFRASTRUCTURE

Behind the Curtain of Business Email Compromise Wire Transfer Attacks

It’s a cautionary tale yet one we see happen over and over - and one that could have cost a company more than $250,000.

Earlier this year, AppRiver’s Advanced Email Filtering service successfully blocked an attempted Business Email Compromise attack in which the malicious actor was seeking a wire transfer totaling more than $250,000.

Here is how it happened.

The attacker was able to compromise the email account of Company A. Once inside the email account, he was able to gather information to initiate an attack.

Once the attacker had what he needed, he went to work crafting a simple invoice email from a vendor Company A had previous and multiple dealings with. To add an air of legitimacy, the attacker went so far as to create a false history of previous responses and dates on the email chain – giving it the appearance of a typical invoice payment request. Taking it one step farther, the cybercriminal registered a domain just one letter different from the vendor’s legitimate domain.

Similar to most higher-end BEC attacks, this one simple invoice led to banking information changes combined with the wire transfer request.

Thankfully, AppRiver’s Advanced Email Filtering service was able to stop the transaction from happening.

How Deep Does This Rabbit Hole Go?

This specific actor/group responsible for the attack had sent two of these wire transfer attacks that same day using the exact same techniques, tactics and procedures. Since their emails were so easily attributable, our curiosity was sparked, we wanted to see how much more could be exposed. We began to perform DNS who is queries and ended up with some common patterns.

The actors had used the same nonexistent street address with minor, but easily recognizable, variations when registering their fictitious domains. That pattern alone made it much easier to find additional information on their attacks. For the domains still active, they use the same hosting provider who specializes in payment via Bitcoins for domain registration and hosting.

During our research, we found other internet posts related to this actor or group on ripoffreport and reddit. These detailed similar scams or fraudulent purchases this same actor/group had used in the past.

After the dust settled, we had uncovered the below:

  • 1,103 fraudulent dspoofing legitimate companies going back to June 2015 – present
  • 293 fictitious personal names used to register the domains (including one Biggy Smallz)
  • 77 unique phone numbers for the registrations

Visualizing the Infrastructure Connections

Pardon the vagueness in defining what every detail means below. However, we wanted to provide a quick visualization of the DNS-related connections they used - without giving away the attacker’s techniques. This way AppRver can continue monitoring them and using intelligence gathered for the benefit of all 60,000+ AppRiver customers.

This first map is a zoomed-out overview of common DNS-related connections utilized by the attackers.

This second visualization, zoomed in a bit more, shows the level of detail and relationships between the fraudulent identities and DNS information connecting them.