BianLian
 

BianLian is a sophisticated and evolving banking trojan that primarily targets Android devices. First observed in 2018, BianLian is known for its complex and constantly evolving nature, making it a significant challenge for mobile security experts. The BianLian banking trojan is disseminated on the Google Play store. Once activated, the malware waits for instructions from Firebase, Google's platform for creating mobile apps. Attackers were able to use Firebase to issue commands to compromised devices. This trojan employs many common techniques, including SMS interception, the ability to lock the device, and overlay attacks to steal credentials.

The name "BianLian" derives from a Chinese opera face-changing technique, highlighting its ability to change tactics and evade detection. The authors of this trojan are known as Hydra, and they've continued to advance the malware's capabilities. In April 2022, a version of the trojan was discovered with capabilities for bypassing photoTAN, an authentication method banks employ to verify online orders. This trojan has been used to target banks in Turkey and Europe.

This trojan applies several techniques to evade detection, including:

• The malware detects if a request came from Google Play Protect. If detected, the trojan functions as a regular app to avoid detection.
• In subsequent releases, the trojan detected if Google Play Protect was running and deactivated the service before the request.
• The attackers obfuscated the code to make the malware more difficult to research.

Threats Posed by BianLian to Your Mobile Banking App:

• Overlay Attacks: BianLian is adept at overlay attacks, a technique that displays a fake login screen or user interface on top of legitimate apps, including mobile banking apps. When users enter their login credentials, they unknowingly provide them to the attacker. Overlay attacks make it difficult for users to distinguish between genuine and fake interfaces.
• Accessibility Services Abuse: BianLian abuses Android's accessibility services designed to assist users with disabilities. By gaining access to these services, the trojan can observe user actions and manipulate app behavior, including interacting with mobile banking apps.
• Dynamic Code Loading: BianLian often uses dynamic code loading techniques, downloading malicious code from remote servers during runtime. Dynamic code loading enables the trojan to change its behavior without requiring a full app update, making it more adaptable to security measures.
• Data Theft: BianLian can capture sensitive information such as login credentials, one-time passwords (OTPs), and personal data. It can also steal SMS messages containing financial transaction details, compromising user accounts.
• Remote Control: The trojan may establish a connection to a command and control (C2) server controlled by attackers. This control server connection allows remote control of infected devices, enabling attackers to initiate unauthorized transactions and manipulate device settings.
• Persistence: BianLian is known for its ability to maintain persistence on infected devices, ensuring that it remains active and can continue to steal information over time.

Mitigating the Threat of BianLian:

To protect your mobile banking app and its users from the BianLian banking trojan and similar threats, consider implementing the following security measures:

• Regular Updates: Keep your mobile banking app up-to-date with the latest security patches and enhancements to address known vulnerabilities.
• User Education: Educate users about downloading the official app from trusted sources and being cautious with app permissions.
• Multi-factor Authentication (MFA): Encourage users to enable MFA for their accounts to add an extra layer of security.
• Real-time Monitoring: Implement real-time monitoring to detect and respond to suspicious activities within your app and network traffic.
• Secure Coding: Follow safe coding practices to prevent vulnerabilities in your app's code, including input validation, data encryption, and secure API communication.
• Third-party Library Review: Carefully review and vet third-party libraries or components used in your app for potential security risks.
• Collaborate with Security Experts: Work with cybersecurity experts to conduct security assessments, code reviews, and penetration testing to identify and address your app's security weaknesses.
• Incident Response Plan: Develop an incident response plan to respond to security incidents or breaches effectively.

What Are The Major Banking Trojan Families?

Some of the central banking trojan families have posed significant threats to mobile banking apps and their users. It's essential to stay informed about these threats, their evolving tactics, and the security measures necessary to protect your app and users against them. Regularly updating your app and following security best practices can help mitigate these risks.

• Anubis: Anubis is an Android banking trojan known for its ability to perform sophisticated financial data theft. It can capture screenshots, record keystrokes, and steal SMS messages, making it highly effective at stealing sensitive banking information. Anubis often masquerades as legitimate apps to trick users.
  
• BankBot: BankBot is an Android banking trojan that spreads through fake apps in third-party app stores. It uses overlay attacks to steal login credentials and intercept SMS messages containing OTPs. BankBot has been a persistent threat in the Android ecosystem.
  
• BianLian: BianLian is a sophisticated and evolving banking trojan that primarily targets Android devices. First observed in 2018, BianLian is known for its complex and constantly evolving nature, making it a significant challenge for mobile security experts. BianLian employs many common techniques, including SMS interception, the ability to lock the device, and overlay attacks to steal credentials.
  
• BrasDex: BrasDex is a sophisticated Android banking trojan that primarily targets banking and financial applications, particularly in Brazil. This trojan has drawn attention because of its ability to manipulate Android’s Accessibility Services, bypass traditional banking security measures, and conduct fraudulent financial transactions through automated systems.
• Cabassous: Cabassous is a modular banking trojan that can be customized to target specific banks and financial institutions. It is typically distributed through SMS phishing messages that contain a malicious link. Once the link is clicked, the trojan is installed on the victim's device. The trojan attempts to prompt users to enter their login credentials using the overlay attack technique.

• Cerberus Trojan: Cerberus is an Android banking Trojan available for rent on underground forums. It features keylogging, screen recording, and remote control of infected devices. Cerberus is regularly updated to evade detection and enhance its capabilities.

• Coper: Coper is a modular banking trojan that can be customized to target specific banks and financial institutions. It is typically distributed through SMS phishing messages that contain a malicious link. Once this malware is installed on the user's device, it leverages social engineering and the accessibility services feature to disable Google Play Protect and install additional malicious apps. 
• Elibomi Malware: Elibomi is Android malware actively targeting users, particularly in India, by masquerading as legitimate applications to steal sensitive personal and financial information. Elibomi typically propagates through SMS phishing (smishing) campaigns.
• Emotet (formerly a banking trojan): Emotet was initially a banking trojan but has evolved into a multifunctional malware platform. It is primarily distributed through malicious email attachments and has been involved in spreading other malware, including ransomware. Emotet's primary goal is to establish a foothold in a system, which can later be used to deliver other malware payloads, including banking trojans.
  
• EventBot: EventBot is a sophisticated Android trojan that targets financial apps, including mobile banking apps. It is known for its advanced capabilities and ability to steal sensitive information from infected devices. EventBot's primary goal is to harvest financial data and credentials to carry out fraudulent transactions and illicit activities.
• ExobotCompact.D: ExobotCompact.D is a banking trojan that steals sensitive information from mobile banking apps. ExobotCompact.D is also known as Octo. It is a modular malware that can be customized to target specific banks and financial institutions. ExobotCompact.d is typically distributed through SMS phishing messages containing malicious links.
• FluBot: FluBot is a sophisticated Android banking trojan that spreads via SMS phishing, enticing users to click on malicious links. FluBot first emerged in late 2020 and focuses on stealing sensitive information, particularly banking credentials and personal data.
• Ginp: Ginp is an Android banking trojan that initially started as a simple SMS stealer but evolved into a more potent threat. It specializes in stealing credit card information by intercepting SMS messages containing card details. Ginp also uses overlay attacks to steal login credentials from banking apps.
  
• Marcher: Marcher is another Android-focused banking Trojan active for several years. It primarily spreads through malicious apps or phishing campaigns and can intercept SMS messages containing OTPs. Marcher has a wide range of targets, including banks in multiple countries.
• Medusa Trojan: The Medusa trojan is a banking trojan that spreads via SMS phishing, enticing users to click on malicious links. Once this trojan is installed, the device user is asked to grant it accessibility services permission, which is used to grant the application more permissions. The trojan features manycapabilities, including keylogging, stealing data from clipboards, screencasting, and sending event logs to a command-and-control server. 
• Mysterybot: Mysterybot is a sophisticated form of Android malware that emerged in mid-2018, combining the functionalities of a banking trojan, keylogger, and ransomware. It explicitly targets banking applications and can steal sensitive data such as login credentials and financial information.
• Nexus Trojan: The Nexus trojan is a sophisticated banking malware that primarily targets Android mobile devices, posing a severe threat to mobile app security, especially for enterprises like e-commerce platforms or retail banks. First detected in early 2023, the Nexus trojan is designed to steal sensitive user data, such as banking credentials, two-factor authentication (2FA) codes, and other personal information.
• Octo: Octo is a banking trojan that steals sensitive data from mobile banking applications. Octo can also be called ExobotCompact.D. It is a modular malware that can be tailored to target specific financial institutions and banks.
• Pixbankbot: Pixbankbot is a sophisticated banking trojan that targets mobile devices designed to infiltrate financial applications and steal sensitive data.
  
• QakBot: QakBot is a sophisticated banking trojan that has evolved into a versatile malware platform. Initially targeting financial institutions, it now poses significant risks to various sectors, including enterprises developing mobile applications.
• SharkBot: SharkBot is a banking trojan that primarily targets money transfers, attempting to exploit the Automatic Transfer Systems (ATS technique that bypasses a bank's multi-factor authentication mechanisms.) When a user tries to transfer funds to another bank account, the malware changes the International Bank Account Number (IBAN entered into the attacker's account.)
• Svpeng: Svpeng is a banking trojan that primarily targets Android devices. It uses overlay attacks to display fake login screens on top of legitimate apps, including mobile banking apps, to steal user credentials. Svpeng is also known for its ransomware capabilities, locking the device and demanding a ransom from the victim.
  
• TeaBot: TeaBot is an Android banking trojan targeting the largest number of mobile financial institutions with more standard features. Once on a victim's device, the trojan checks which applications are installed, and once a targeted banking app is discovered, it downloads a payload specifically for that app. TeaBot typically spreads through malicious apps or phishing campaigns.
• Xenomorph: Xenomorph is a banking trojan that was distributed on the Google Play app store, billed as a "Fast Cleaner" app. More than 50,000 users downloaded Xenomorph. Xenomorph employs many common trojan tactics, such as stealing SMS messages, intercepting notifications, bypassing two-factor authentication, and using overlay attacks to steal credentials. 
• Zbot: Zbot, also known as Zeus, is one of the most notorious banking trojans. It primarily targets Windows devices but has variants that affect mobile platforms. It is known for its sophisticated capabilities, including keystroke logging, form grabbing (capturing data entered into web forms), and man-in-the-browser attacks. Zbot variants often use social engineering techniques to trick users into downloading malicious files or clicking on malicious links.