A Spanish-speaking cybercrime group named GXC Team has been observed bundling phishing kits with malicious Android applications, taking malware-as-a-service (MaaS) offerings to the next level.
Singaporean cybersecurity company Group-IB, which has been tracking the e-crime actor since January 2023, described the crimeware solution as a "sophisticated AI-powered phishing-as-a-service platform" capable of targeting users of more than 36 Spanish banks, governmental bodies, and 30 institutions worldwide.
The phishing kit is priced anywhere between $150 and $900 a month, whereas the bundle including the phishing kit and Android malware is available on a subscription basis for about $500 per month.
Targets of the campaign include users of Spanish financial institutions, as well as tax and governmental services, e-commerce, banks, and cryptocurrency exchanges in the United States, the United Kingdom, Slovakia, and Brazil. As many as 288 phishing domains linked to the activity have been identified to date.
Also part of the spectrum of services offered are the sale of stolen banking credentials and custom coding-for-hire schemes for other cybercriminal groups targeting banking, financial, and cryptocurrency businesses.
"Unlike typical phishing developers, the GXC Team combined phishing kits together with an SMS OTP stealer malware pivoting a typical phishing attack scenario in a slightly new direction," security researchers Anton Ushakov and Martijn van den Berk said in a Thursday report.
What's notable here is that the threat actors, instead of directly making use of a bogus page to grab the credentials, urge the victims to download an Android-based banking app to prevent phishing attacks. These pages are distributed via smishing and other methods.
Once installed, the app requests for permissions to be configured as the default SMS app, thereby making it possible to intercept one-time passwords (OTPs) and other messages and exfiltrate them to a Telegram bot under their control.
"In the final stage the app opens a genuine bank's website in WebView allowing users to interact with it normally," the researchers said. "After that, whenever the attacker triggers the OTP prompt, the Android malware silently receives and forwards SMS messages with OTP codes to the Telegram chat controlled by the threat actor."
Among the other services advertised by the threat actor on a dedicated Telegram channel are AI-infused voice calling tools that allow its customers to generate voice calls to prospective targets based on a series of prompts directly from the phishing kit.
These calls typically masquerade as originating from a bank, instructing them to provide their two-factor authentication (2FA) codes, install malicious apps, or perform other arbitrary actions.
"Employing this simple yet effective mechanism enhances the scam scenario even more convincing to their victims, and demonstrates how rapidly and easily AI tools are adopted and implemented by criminals in their schemes, transforming traditional fraud scenarios into new, more sophisticated tactics," the researchers pointed out.
In a recent report, Google-owned Mandiant revealed how AI-powered voice cloning has the capability to mimic human speech with "uncanny precision," thus allowing for more authentic-sounding phishing (or vishing) schemes that facilitate initial access, privilege escalation, and lateral movement.
"Threat actors can impersonate executives, colleagues, or even IT support personnel to trick victims into revealing confidential information, granting remote access to systems, or transferring funds," the threat intelligence firm said.
"The inherent trust associated with a familiar voice can be exploited to manipulate victims into taking actions they would not normally take, such as clicking on malicious links, downloading malware, or divulging sensitive data."
Phishing kits, which also come with adversary-in-the-middle (AiTM) capabilities, have become increasingly popular as they lower the technical barrier to entry for pulling off phishing campaigns at scale.
Security researcher mr.d0x, in a report published last month, said it's possible for bad actors to take advantage of progressive web apps (PWAs) to design convincing login pages for phishing purposes by manipulating the user interface elements to display a fake URL bar.
What's more, such AiTM phishing kits can also be used to break into accounts protected by passkeys on various online platforms by means of what's called an authentication method redaction attack, which takes advantage of the fact that these services still offer a less-secure authentication method as a fallback mechanism even when passkeys have been configured.
"Since the AitM can manipulate the view presented to the user by modifying HTML, CSS, and images, or JavaScript in the login page, as it is proxied through to the end user, they can control the authentication flow and remove all references to passkey authentication," cybersecurity company eSentire said.
The disclosure comes amid a recent surge in phishing campaigns embedding URLs that are already encoded using security tools such as Secure Email Gateways (SEGs) in an attempt to mask phishing links and evade scanning, according to Barracuda Networks and Cofense.
Social engineering attacks have also been observed resorting to unusual methods wherein users are enticed into visiting seemingly legitimate-but-compromised websites and are then asked to manually copy, paste, and execute obfuscated code into a PowerShell terminal under the guise of fixing issues with viewing content in a web browser.
Details of the malware delivery method have been previously documented by ReliaQuest and Proofpoint. McAfee Labs is tracking the activity under the moniker ClickFix.
"By embedding Base64-encoded scripts within seemingly legitimate error prompts, attackers deceive users into performing a series of actions that result in the execution of malicious PowerShell commands," researchers Yashvi Shah and Vignesh Dhatchanamoorthy said.
"These commands typically download and execute payloads, such as HTA files, from remote servers, subsequently deploying malware like DarkGate and Lumma Stealer."
