Trickbot
Trickbot is a modular banking trojan malware targeting Microsoft Windows systems, initially detected in 2016 and designed for credential theft via phishing-delivered payloads that enable web injection attacks on financial institutions.[1][2] Over time, it evolved into a versatile, multi-phase platform capable of installing persistent backdoors, harvesting system information for reconnaissance, executing lateral movement within networks, and downloading secondary malware such as ransomware variants including Ryuk and Conti.[3][4][5] Deployed by organized cybercrime actors through mass email campaigns often masquerading as legitimate invoices or updates, Trickbot has infected over a million devices worldwide, targeting sectors from healthcare to finance and generating revenue for operators via credential sales, malware leasing, and ransomware facilitation.[6][7] Notable disruptions include a 2020 international operation led by Microsoft, in coordination with U.S. Cyber Command and partners, which neutralized numerous command-and-control servers, though operators quickly adapted by deploying new infrastructure and variants to restore functionality.[8][9] Subsequent actions in 2024 against associated droppers like Smokeloader and Bumblebee further targeted its distribution ecosystem, underscoring Trickbot's role as a resilient enabler in the cybercrime economy despite repeated law enforcement interventions.[10][11]History
Origins and Initial Deployment (2016)
TrickBot emerged in 2016 as a modular banking Trojan developed by an organized cybercrime group, primarily targeting the theft of financial credentials and data from infected systems.[4][2] The malware was first observed in the wild during that year, exhibiting structural and operational similarities to earlier credential-stealing Trojans such as Dyre (also known as Dyreza), including communication with command-and-control (C2) servers for data exfiltration.[1][12] Initially designed for financially motivated attacks, TrickBot focused on intercepting banking-related inputs via form-grabbing techniques and keylogging, enabling operators to harvest login details for unauthorized access to online accounts.[13] Initial deployments relied on phishing campaigns, often delivered through malspam emails containing malicious links or attachments that prompted users to enable macros in Microsoft Office documents, thereby installing the TrickBot binary.[1] These emails typically masqueraded as legitimate communications to lure victims into executing the payload, which then established persistence on Windows systems and beaconed to C2 infrastructure for further instructions.[2] The malware's early variants demonstrated basic modularity, allowing for credential theft modules tailored to specific banking institutions, though it lacked the advanced lateral movement or ransomware capabilities seen in later iterations.[12] By late 2016, TrickBot had begun targeting users in Europe and North America, capitalizing on its evasion tactics like process injection to avoid detection by contemporary antivirus software.[1] The cybercrime actors behind TrickBot operated as a resilient group, using underground forums for distribution and monetization, with initial infections serving as entry points for direct financial fraud rather than broader network compromise.[4] No public attribution to specific individuals occurred at the time, but the malware's code quality and rapid updates indicated professional development by threat actors likely based in Eastern Europe.[2] This foundational phase established TrickBot as a persistent threat, with early campaigns demonstrating its adaptability to regional banking targets through customizable modules.[12]Modular Evolution and Growth (2017-2019)
During 2017, Trickbot transitioned from a primarily banking-focused trojan to a more versatile modular platform by incorporating a worm module for lateral movement across networks, drawing inspiration from exploits like those in WannaCry.[3][1] This enabled automated propagation via SMB vulnerabilities, while new capabilities targeted Outlook credentials to facilitate email-based spreading, potentially compromising millions of corporate accounts.[3][1] Data exfiltration expanded to include browser cookies, history, visited URLs, and Adobe Flash Local Shared Objects, enhancing credential theft beyond financial institutions.[3] On April 20, 2017, developers added the bcClientDll32 module, providing reverse proxy functionality via SOCKS5 for remote access and tunneling.[14] In 2018, Trickbot's modular architecture saw further refinements, including a PowerShell-based module to disable Windows Defender, improving evasion against endpoint security.[3] Code obfuscation techniques were integrated to hinder reverse engineering and detection by antivirus tools.[3] The malware's attack volume surged, accounting for 12.85% of unique banking trojan incidents globally, with operations targeting financial services in 65 countries—expanding to 11 new nations that year, including heavy focus on the UK (11.02%), US (9.34%), and Germany (7.99%).[15] On January 16, 2018, the domainDll32 module was introduced to enumerate domain controllers and gather Active Directory intelligence, aiding deeper network reconnaissance.[14] By year's end, Trickbot overtook Emotet as a leading threat to businesses, reflecting its operators' emphasis on scalability and multi-vector delivery.[3][1] By 2019, updates emphasized stealth and targeted expansion; early in the year, the injectDll32 module was enhanced to hook Windows networking APIs alongside traditional web injections for banking sites.[14] Web injection templates were updated to phish credentials from US mobile carriers like Sprint, Verizon, and T-Mobile.[3] The Mworm propagation module was replaced with Nworm, which operated in memory to avoid disk artifacts and manipulated HTTP traffic for better evasion.[3] On October 8, 2019, the anubisDll32 module debuted, incorporating man-in-the-browser attacks with ties to IcedID banking trojan elements and VNC remote control.[14] EternalBlue exploits were integrated for worm-like spreading, contributing to compromises of over 250 million email accounts by mid-year.[12] These enhancements solidified Trickbot's role as a flexible downloader for secondary payloads, driving its growth into a multi-stage infection toolkit.[12][1]Ransomware Integration and Peak Activity (2020-2021)
In 2020, Trickbot malware operators expanded its modular architecture to serve as an initial access vector for ransomware deployments, particularly Ryuk, by incorporating capabilities for network reconnaissance, credential theft via tools like Mimikatz, and lateral movement over SMB protocols.[8][4] These enhancements allowed infected systems to enumerate domains, harvest administrator credentials, and exfiltrate data to command-and-control servers, paving the way for subsequent ransomware payloads.[4] Trickbot's role shifted from primary banking trojan functions to a versatile dropper, often following initial infections via Emotet or phishing emails containing malicious Office macros or JavaScript.[8] Ryuk ransomware integrations peaked in mid-2020, with Trickbot facilitating targeted attacks on enterprises, including healthcare providers, amid heightened cybercrime activity during the COVID-19 pandemic.[16] For instance, campaigns in June 2020 exploited current events like COVID-19 and social movements for phishing lures, leading to widespread Trickbot infections that enabled Ryuk encryption and ransom demands averaging millions of dollars per victim.[8] By October 2020, Trickbot and associated trojans like Emotet were linked to a documented spike in ransomware incidents, with cybersecurity firms reporting Trickbot as a key enabler in human-operated attacks on critical infrastructure.[16] A coordinated disruption effort on October 12, 2020, by Microsoft, ESET, and other firms neutralized much of Trickbot's command-and-control infrastructure, reducing active botnet nodes by over 90% initially.[8] However, operators quickly rebuilt variants, sustaining high activity into 2021, where Trickbot ranked as the most prevalent malware in global detections for months including June and September.[17][18] In this period, Trickbot also supported Conti ransomware initial access, contributing to nearly 450 reported global Conti attacks, many targeting U.S. critical infrastructure.[19][20] This resurgence underscored Trickbot's adaptability, with modules updated for evasion and persistence, such as UEFI/BIOS enumeration for deeper system control.[4]Disruptions and Partial Takedowns (2021-2022)
In early 2021, Trickbot demonstrated resilience following the partial infrastructure disruptions of October 2020, surging in prevalence as it capitalized on the takedown of rival botnets like Emotet in January 2021.[21] Security firms reported Trickbot impacting approximately 3% of global organizations in February 2021, with aggressive distribution via malicious spam campaigns targeting sectors such as legal and insurance.[21] By September and October 2021, it topped malware rankings, affecting up to 11% of corporate networks in some analyses, often serving as a dropper for ransomware payloads.[18] [22] Activity began waning in late 2021, with no new command-and-control (C2) servers registered after December 16, 2021, signaling operational shifts by the Russia-based Wizard Spider group.[23] Operators increasingly abandoned Trickbot for alternatives like Emotet and BazarBackdoor, migrating controlled infected devices to these platforms due to Trickbot's high detection rates, recognizable network traffic, and reduced efficiency for targeted intrusions.[24] [23] This internal pivot, rather than a comprehensive external takedown, marked a partial dismantling, as core developers and penetration testers were recruited by the Conti ransomware syndicate to bolster its capabilities, including Active Directory exploits.[25] [23] On February 24, 2022, Trickbot's botnet infrastructure was formally shuttered, ending over five years of operation that had involved investments exceeding $20 million.[23] [26] The shutdown followed months of inactivity, with operators redirecting efforts to stealthier malware families; new Emotet C2 servers appeared as early as February 19, 2022, and BazarBackdoor infrastructure activated shortly thereafter.[23] While this effectively neutralized Trickbot's global footprint, remnants persisted through Conti integrations, and U.S. Department of Justice indictments in 2023 referenced the 2022 takedown as a key milestone in curbing its ransomware-enabling role.[27] No full recovery occurred, contrasting with post-2020 rebounds, as threat actors prioritized evasion over maintaining the aging platform.[28]Technical Architecture
Core Design and Components
Trickbot employs a modular architecture centered on a persistent loader component that serves as the foundational element for downloading, decrypting, and executing specialized DLL modules from command-and-control (C2) servers. The loader, typically a 32-bit or 64-bit Windows PE executable or DLL delivered via initial infection vectors, establishes system persistence by copying itself to directories such as %AppData%[Roaming](/page/Roaming) and %Temp%, and scheduling tasks like "SpeedNetworkTest" to ensure regular execution.[29][2] This design, implemented primarily in C++, enables dynamic adaptability, where the loader handles core functions like C2 communication over HTTP/HTTPS to hardcoded IP addresses and ports (e.g., 185.20.184.74:8082 or 103.119.144.250:8082), using GET requests formatted with bot identifiers and group tags (gtag) to fetch encrypted modules.[29][14] Upon initialization, the loader decrypts modules using a system-generated botkey derived from machine-specific data, such as hardware identifiers, and loads them into memory via techniques like DLL injection to evade static detection. Modules are stored in a dedicated "Data" folder post-decryption and executed based on C2 directives, supporting both static and dynamic configurations for flexibility across Windows environments. This core loader also incorporates evasion primitives, including disabling Windows Defender via registry modifications and process hollowing to mask malicious activities.[29][14] Essential components include the anchor module for primary C2 orchestration and heartbeat signaling, the inject DLL (e.g., injectDll64.dll or injectDll32.dll) for hooking browser APIs like ws2_32::connect() and certificate validation functions to facilitate man-in-the-browser attacks, and reconnaissance modules such as systeminfo64.dll for enumerating system details like browser data from registry keys (e.g., IntelliFormsStorage2). Additional core elements encompass persistence mechanisms and a worm-like propagation framework exploiting SMB vulnerabilities for lateral movement, underscoring the design's emphasis on extensibility over monolithic functionality.[29][14][1]Modular Structure and Updates
TrickBot's architecture is built around a modular framework featuring a persistent loader component that fetches and injects dynamic-link library (DLL) modules from command-and-control (C2) servers over HTTPS connections.[4] These modules, often encrypted with AES in CBC mode using 256-bit keys and obfuscated via custom packers, handle discrete tasks such as credential harvesting, web injection, and network propagation, allowing the malware to function as a versatile platform rather than a monolithic binary.[4] The loader establishes persistence through scheduled tasks triggering every 11 minutes and stores modules in directories like%AppData%\Roaming.[30]
Updates occur dynamically via C2 directives, where the malware polls for configuration files, new modules, or Base64-encoded commands, including fallback channels for resilience against disruptions.[4] This command-driven model enables rapid iteration, with modules downloaded on demand—such as through command "5" for injection into processes like [svchost.exe](/page/Svchost.exe) using process hollowing techniques—and reported back via HTTP POST requests.[31] Operators leverage this to evade detection by incorporating anti-analysis measures like encrypted strings, dynamic API resolution, and delays (e.g., 3000ms post-infection).[30][31]
Early enhancements in 2017 introduced modules like the worm-like mwormDll64 for lateral movement via SMB and LDAP, alongside an Outlook credential stealer targeting corporate email accounts.[1][30] In October 2018, the pwgrab module was deployed to extract autofill data, history, and credentials from browsers (e.g., Chrome's SQLite "Login Data.bak") and tools like WinSCP, using threaded operations and reporting to specific C2 IPs.[31] By September 2019, payloads incorporated importDll64 for browser data theft and injectDll64 for site-specific web injections targeting over 25,000 domains with wildcard support, plus RSA encryption and Windows Defender disablement via PowerShell.[30]
Later modules expanded reconnaissance, including UEFI/BIOS enumeration for firmware persistence attempts, and supported cryptomining or exfiltration payloads.[4] This iterative modularization, with samples recompiled frequently (e.g., 2019-09-16 builds), sustained TrickBot's adaptability until infrastructure takedowns in 2021-2022 curtailed major updates.[30][1]
Capabilities
Credential Theft and Banking Functions
TrickBot originated in 2016 as a banking trojan specifically engineered to harvest financial credentials, succeeding the Dyre malware and targeting users' banking information through sophisticated injection techniques.[8][1] Its core banking functionality revolves around person-in-the-browser attacks, where it employs web injects to overlay malicious content on legitimate banking websites, capturing usernames, passwords, and other sensitive data entered by victims.[4] These injects often leverage browser redirection and server-side modifications to create fake login pages or alter form fields, facilitating credential theft without alerting the user.[1] The malware's modular architecture includes dedicated components for credential access, such as the injectDll module, which serves as the primary banker payload responsible for browser injections and exfiltrating financial data to command-and-control servers.[8] Complementing this, the pwgrab module systematically extracts stored credentials from web browsers—including Chrome, Firefox, and Internet Explorer—along with autofill data, form histories, and cookies, broadening the scope beyond real-time captures to include previously saved banking details.[8][4] Additional modules like outlookDll target email credentials, which operators use to enable further phishing or account compromises tied to financial services, while psfin focuses on point-of-sale software to steal transaction-related credentials.[8] Credential theft extends to system-level techniques, including API hooking via functions like CredEnumerateA to intercept Remote Desktop Protocol logins and queries against Windows Credential Manager or Vault for stored passwords.[4] TrickBot also scans registry keys and unsecured files for credentials from applications such as PuTTY or FileZilla, which may contain saved banking or remote access details relevant to financial operations.[4] These harvested credentials enable downstream activities like wire fraud, unauthorized transfers, and account takeovers, with exfiltrated data often sold on underground markets or used directly by affiliated actors.[1] The modular updates, observed as early as 2017, allow rapid adaptation of injection scripts to evade detection by specific banks, ensuring sustained efficacy in credential theft campaigns.[1]System Reconnaissance and Lateral Movement
TrickBot employs modular plugins to conduct extensive system reconnaissance, enabling operators to profile infected hosts and networks for subsequent exploitation. Upon infection, it gathers detailed system information, including operating system version, CPU architecture, RAM capacity, machine hostname, and UEFI/BIOS details, often via APIs like WMI or direct registry queries.[32][4] The malware also enumerates running processes, installed services, user accounts, and local groups to assess privileges and potential persistence opportunities.[4][33] A key component for network-oriented reconnaissance is the networkDLL plugin, introduced around 2018, which executes Windows commands such asipconfig /all for TCP/IP configuration, net config workstation for domain or workgroup details, net view /all for accessible shares, and nltest /domain_trusts /all_trusts for enumerating trusted domains.[33] This module further leverages Active Directory interfaces like IADsADSystemInfo to retrieve domain DNS names, site names, and forest details, while querying LDAP for domain controllers, user accounts (e.g., sAMAccountName), and host attributes (e.g., dNSHostname).[33] Additional modules, such as shareDLL or mshareDLL, discover network shares using APIs like WNetOpenEnumA, facilitating mapping of accessible resources.[32] The masrvDLL incorporates tools like Masscan to scan and enumerate remote systems, identifying live hosts and open ports for targeted propagation.[34]
For lateral movement, TrickBot exploits stolen credentials and vulnerabilities to propagate within networks, often prioritizing SMB-dependent environments. It abuses the Server Message Block (SMB) protocol through worm-like modules such as WormDLL and ShareDLL, which scan for vulnerable shares and attempt connections using harvested passwords or brute-force lists derived from prior credential theft.[34][4] The TabDLL module deploys exploits like EternalRomance (CVE-2017-0147) over SMBv1 to execute payloads remotely without authentication.[34][35] Complementing these, the rdpScanDLL brute-forces Remote Desktop Protocol (RDP) credentials to enable logon and payload deployment on adjacent systems.[36] For sustained access, modules like vncDLL establish Virtual Network Computing (VNC) sessions, allowing remote control and pivoting to high-value targets.[32] The SqulDLL enhances movement by enabling WDigest authentication and dumping credentials via Mimikatz-like functionality for reuse in lateral propagation.[34] These techniques, observed consistently from 2018 onward, prioritize efficiency in enterprise networks, often combining reconnaissance data to select paths minimizing detection risk.[36][37]
Payload Delivery and Ransomware Deployment
TrickBot employs a modular loader that communicates with command-and-control (C2) servers over HTTPS to download configuration files and additional modules, enabling the dynamic delivery of secondary payloads tailored to specific objectives.[8] These modules, such aspwgrab for credential harvesting and injectDll for process injection, are decrypted at runtime and executed to expand capabilities, including the injection of payloads into legitimate processes like svchost.exe for evasion.[8] The core design facilitates payload persistence through scheduled tasks and registry modifications, allowing subsequent downloads of tools like Cobalt Strike beacons for further exploitation.[4]
In ransomware deployment scenarios, TrickBot serves as an initial access vector and reconnaissance platform rather than a direct dropper, with human-operated actors leveraging its foothold for manual escalation. Following infection, modules like dll.dll execute system enumeration commands (e.g., ipconfig, net, nltest) and deploy PowerShell-based tools such as Empire for port scanning and asset discovery, identifying high-value targets like domain controllers.[38] Lateral movement occurs via SMB propagation, credential dumping with Mimikatz, and exploits like EternalBlue, often after disabling defenses such as Windows Defender.[4][38]
This reconnaissance phase transitions to ransomware execution, as observed in campaigns linking TrickBot to Ryuk since at least December 2018, where operators use RDP, PsExec, or batch scripts to deploy the encryptor on critical systems after dwell periods ranging from days to over a year.[39] For instance, in tracked operations attributed to groups like TEMP.MixMaster, TrickBot's network propagation modules (e.g., sharedll, tabdll) spread to dozens to hundreds of hosts, enabling data exfiltration before Ryuk encryption, which has yielded millions in Bitcoin ransoms.[39] Similar patterns extend to other ransomware variants, including Conti and Princess, facilitated by TrickBot's C2-directed exfiltration and module synchronization.[4][8]