Dubai, UAE: Smishing, a cyberattack strategy that combines SMS (short message service, also known as text messages) and phishing, has been revealed as a new and sophisticated mechanism to obtain personal and financial information from victims, through false forms on fraudulent sites.

A wave of VexTrio attacks using dictionary domain generation algorithm (DDGA) has infected numerous websites built on Wordpress, which in turn infect visitors to those sites with malware or spyware by executing Javascript code.

Infoblox Inc., a leader in secure and cloud-managed network services, has published a new edition of the company’s Quarterly Cyber Threat Intelligence Report, a security intelligence report that compiles the main threats and security breaches detected during the previous three months on a quarterly basis worldwide. Among the main conclusions of this report, which covers the months of April to June 2022, are:

Smishing - a strategy that combines SMS and phishing

Smishing messages are sent by bad actors to get victims to reveal private information, including passwords, identity and financial data. The messages typically include some incentive for the recipient to click a link, which may be for a site that hosts malware or a page that attempts to convince the user to submit data through a form.

Actors have regularly used spoofed sender numbers in the text messages to evade spam filters. However, those messages that are not automatically detected by the mobile provider can be stopped by blocking the sender’s phone number. In response, threat actors continue to evolve their own techniques. In a well-known version of mobile phone spoofing, a recipient receives a text or phone call from someone who appears to be in the area close to the recipient. Users are hesitant to block local phone numbers for fear it would also block legitimate phone calls and messages.

Spoofing the recipient’s phone number is another advance by actors to overcome spam filtering and blocking and to convince users to click on the embedded links in the messages.

Prevention and Mitigation

Smishing messages are a common method for sending phishing links. Infoblox recommends the following precautions for avoiding smishing attacks:

  • Always be suspicious of unexpected text messages, especially those that appear to contain financial or delivery correspondences, documents or links.
  • Never click URLs in text messages from unknown sources. In the campaign under discussion, the source was the recipient, who did not send the message, and that is a red flag.

VexTrio DDGA Domains Spread Adware, Spyware and Scam Web Forms

Since February 2022, Infoblox’s Threat Intelligence Group (TIG) has been tracking malicious campaigns that use domains generated by a dictionary domain generation algorithm (DDGA) to run scams and spread riskware, spyware, adware, potentially unwanted programs and pornographic content. This attack is widespread and impacts targets across many industries.

VexTrio actors heavily use domains and the DNS protocol to operate their campaigns. The actors leverage vulnerable WordPress websites as attack vectors to serve fraudulent content to unknowing website visitors. To accomplish this, they first detect websites that show cross-site scripting (XSS) vulnerabilities in WordPress themes or plugins, then inject malicious JavaScript code into them. When victims visit these websites, they are led to a landing web page that hosts fraudulent content, via one or more intermediary redirect domains that are also controlled by the actors. Additionally, as a means to avoid detection, the actors have integrated several features into their JavaScript and require the following conditions from the user to trigger the redirect:

  • The user must visit the WordPress website from a search engine. For example, the referrer URL can be https://www.google.com/.
  • Cookies are enabled in the user’s web browser.
  • The user has not visited a VexTrio compromised web page in the past 24 hours.

Prevention and mitigation

VexTrio primarily abuses vulnerable WordPress websites to deliver unwanted content to visitors. Embedding malicious JavaScript code in oft-visited web blogs and other popular but vulnerable websites helps the actors widen their reach. Infoblox assesses the VexTrio DDGA campaign could serve as a delivery vector for other cyber crime syndicates and thereby enable follow-on attacks. Infoblox recommends the following actions for protection from this kind of attack:

  • Disabling JavaScript on web browsers completely, or enabling it only for trusted sites, can help mitigate attacks employed by VexTrio actors, who capitalize on the use of JavaScript to run their tasks.
  • Consider using an adblocker program to block certain malware activated by popup ads. Along with an adblocker, consider using the web extension NoScript, which allows JavaScript and other potentially harmful content to execute only from trusted sites to reduce the attack surface available to actors.
  • Implementing Infoblox’s RPZ feeds in firewalls can stop the connection by actors at the DNS level, as all components described in this report (compromised websites, intermediary redirect domains, DDGA domains and landing pages) require the DNS protocol. TIG detects these components daily and adds them to Infoblox’s RPZ feeds.
  • Leveraging Infoblox’s Threat Insight service, which performs real-time streaming analytics on live DNS queries, can provide high-security coverage and protection against threats that are based on DGA as well as DDGA.

Newly Observed Domains and the Ukraine War

The surge in registration and observation of new domains related to the Russian invasion of Ukraine has been over for some time. Nevertheless, Infoblox research shows that low levels of new phishing campaigns, donation scams, and other suspicious activities are still being launched in attempts to take advantage of Ukraine’s crisis.

Overall, data shows that the volume of legitimate domains is greater than malicious websites in Infoblox’s environment. The surge in newly observed domains began in the first week after the invasion (the beginning of March). For several weeks, many legitimate sites were created to help provide relief to the people of Ukraine; however, cyber threat actors and scammers also took advantage of the crisis, creating their own sites and adding to the volume of newly observed domains. By the end of March (week 13), the number of domains started to decrease, and the number of newly observed domains in Infoblox’s data began to stabilize. The most recent trends, beginning in April (week 14), show that, on average, there continues to be a higher – though only slightly – number of newly observed domains (legitimate and suspicious/malicious) in comparison to before the invasion.

Although the number of malicious domains is trending down, users should remain vigilant. From previous experience, bad actors will continue to exploit individuals through email, malvertising, and other means as long as they can. For comparison, while covid related malware campaigns peaked in 2020, we still see them two years later. Users should carefully inspect requests for donations from organizations they are not familiar with and they should not click on links from unknown sources.

Mohammed Al-Moneer, Regional Director, META at Infoblox says, “Our report shares research on many dangerous malware threats. Security effectiveness depends on timely, up-to-date threat intelligence. Using tools included in Infoblox BloxOne Threat Defense, security teams can collect, normalize and distribute highly accurate, multi-sourced threat intelligence to strengthen the entire security stack. Additional capabilities can help SecOps to accelerate threat investigation and response by up to two-thirds.”

The Infoblox Q2 2022 Cyber Threat Intelligence Report can be downloaded here.

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About Infoblox

Infoblox delivers the next-level network experience with its Secure Cloud-Managed Network Services. As the pioneer in providing the world’s most reliable, secure and automated networks, we are relentless in our pursuit of next level network simplicity. A recognized industry leader, Infoblox has more than 12,000 customers, including over 70% of the Fortune 500. Learn more at https://www.infoblox.com.