In our last blog, we highlighted how banking trojans are a threat to banking customers and small businesses, normally delivered via phishing emails containing malicious attachments. While phishing is a threat to businesses and individuals in all industries, attackers targeting financial services organizations often use highly-crafted social engineering tactics to make sure they hit their mark. In the third blog of the series, we’ll take a deeper look into the techniques used to phish financial organizations, as well as ways in which you can mitigate these attacks.
What is phishing?
Phishing is a tactic where the attacker poses as a legitimate individual or service to gather sensitive information such as credentials or payment card information, or install malware on the target’s device. This is usually achieved either with an email containing a malicious attachment, or a URL link that will redirect the victim to a malicious domain where they will be asked to provide sensitive information or install plug-ins.
Email phishing campaigns can be wide and indiscriminate in their targeting, hoping that recipients will not recognise the fraudulent nature of the email. In many cases these emails are used to deliver malware such as the banking trojans.
What is Spear Phishing?
Spear phishing is a form of phishing that targets a specific individual or organization. Frequently, the emails are tailored to the recipient to make it more believable. Two common types of spear phishing are:
- Business Email Compromise (BEC). There are many different versions of BEC, but in one popular method the attacker will either spoof an executive’s email address and impersonate them, or even used a compromised business email account, to get an employee, customer or supplier to transfer funds or sensitive information to the phisher.
- Whale phishing (or Whaling). Another form of BEC, although high-level executives are the target. Attackers can use information pertaining to the executive found on public sources, including their name, phone number, email, or professional address when selecting their targets and developing social engineering tactics.
Phishing Financial Organizations
Knowing your target
An attacker will often spend considerable time investigating their target, so they can tailor the email to them and make it as compelling as possible. In recent years we’ve seen threat groups specializing in specific industries and geographies, resulting in a high level of sophistication in their attacks.
Let’s take the example of the Carbanak malware, which has been associated with several different campaigns against financial institutions, retail businesses, ATM systems and point-of-sale service providers. As the malware is in public circulation, it has been attributed to more than one group, including both the Carbanak group and FIN7. It’s unclear whether these groups are associated or simply share use of the malware and similar tools.
Operators of the Carbanak malware use social engineering techniques such as spear phishing in combination with malicious attachments containing the malware. When targeting financial companies, the emails are tailored to employees, appearing to have been written by native English speakers familiar with both investment terminology and the inner workings of public companies (see Figure 1 below). The emails frequently play up shareholder and public disclosure concerns.
Figure 1: Example of FIN7 phishing email (Source: FireEye)
Digital Shadows (now ReliaQuest) recently discovered files and source code that were allegedly related to the Carbanak group. Whatever the actual provenance of the leaked source code and files, these findings provided significant insights on how criminal groups target financial organizations with a level of sophistication that displays a strong understanding of the industry. The files not only contained the malware used to target the organizations, but also included detailed information on banking systems, instructions on how to make fraudulent payments and bypass anti-fraud features, and a list of key personnel responsible for payment processing in each of the target banks.
But how can attackers collect the information needed to learn about their targets and make their emails more believable? An open source investigation can provide a lot of information during the reconnaissance phase of the attack. An attacker will try to find any social media accounts pertaining to their victim(s), credentials found in past breaches, email and phone numbers in company material, personal addresses and emails linked to possible domains registered under the individual or provided in public company registries and assets under their name. The most sophisticated attackers, such as the Carbanak group, will often have contacts or insiders within financial organizations who can provide them with more specialized information or even privileged access to perform their operations.
Low barriers to entry
The lack of technical background or unfamiliarity with financial services terminology is not a hindrance to someone who wants to perform a phishing attack. If the attacker cares about harvesting credentials and credit card information from opportunistic targets, ‘finesse’ and technical capability is not a primary requirement. In many criminal marketplaces, aspiring attackers can find listings for complete phishing pages, usually clones of known organizations, that anyone can buy along with instructions on how to use them (See Figures 2 and 3).
Figure 2: Listing offering phishing pages for sale (Source: n0va[.]shop)
Figure 3: Tutorial on how to create a phishing page (Source: xplace[.]com)
Business Email Compromise
During a BEC, the attacker will impersonate a company executive and attempt to get an employee, customer or supplier to transfer funds or sensitive information to the phisher. A 2017 advisory from the Federal Bureau of Investigation’s (FBI) Internet Crimes Complaint Centre (IC3) reported that BEC attacks between October 2013 and December 2016 caused worldwide losses totalling over $5 billion. Recently, a six-month coordinated global law enforcement effort under the name “Operation Wire Wire” targeted business email compromise schemes, which resulted in 74 arrests.
Two highly publicized BEC attacks that hit the news in recent years are those that targeted Xoom and Scoular. Both are financial companies where spoofed emails were sent to their employees, resulting in transfers of millions of dollars to third party accounts. In Xoom’s case the emails targeted their finance department, while in Scoular’s the emails impersonated the company CEO. In some scenarios, if the attacker is familiar with the organization and its processes, they could also take advantage of real life events such as tax deadlines or impending financial deals to make their phishing attempt more believable.
Mitigating phishing attacks
Standard countermeasures such as anti-spam filters and anti-malware protections will usually filter out part of these types of scam emails; however, they are not fool-proof, especially against the most targeted attacks such as spear phishing and whaling. Organizations should therefore look to adopt a broader approach, which can include:
- Educating your team. Organizations should heavily invest on educating their personnel against these types of attacks and how to recognise them. Update your security awareness training content to include the BEC scenario. This should be a part of new hire training, but you should conduct ad-hoc training for this scenario as well. Additionally, employees should only have access to the infrastructure and resources appropriate for their position and level, that way even if they are compromised the attacker will be limited to that part of the company network. Two-factor authentication should also be required as part of the company’s security policy.
- Updating your incident response strategy. You need to build BEC into your contingency plans, just as you have built ransomware and destructive malware into your incident response/business continuity planning.
- Introducing continuous monitoring. Conduct ongoing assessments of your executive’s digital footprints. You can start with using Google Alerts to track new web content related to them.
- Enhancing company policies around wire transfers. Work with your wire transfer application vendors to build in multiple person authorizations to approve significant wire transfers and prevent successful BEC attempts against your organization.
- Establishing an OPSEC Program. Formalize an Operations Security (OPSEC) program. Organizations and their employees often, unknowingly, expose detailed personal information or information about the systems and third parties they use on social media and other sources. In the wrong hands, this information can be used effectively to socially engineer a target.
In our next blog of the threats to financial services series, we’ll cover everything you need to know about payment card fraud. Stay tuned.
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