CTIPilot

SparroWocky

malware · malware:sparrowocky single-source

Modular C++ backdoor that replaced SparrowDoor as FamousSparrow's flagship implant from August 2025; incorporates Mbed TLS, MinHook and a modified COFF Loader for Beacon Object File execution, with SilentMoonwalk call-stack spoofing and PEB_LDR_DATA forgery for anti-analysis (ESET, 2026-09-17).

Coverage timeline
1
first 2026-09-18 → last 2026-09-18
Peak priority
notable
1 notable
Sources cited
1
1 hosts
Sections touched
1
active-threats
Co-occurring entities
1
see Co-occurring entities below
ATT&CK techniques
34
pinned v19.2 · see below

ATT&CK techniques

34 techniques observed across 1 entry, derived from entry metadata and body evidence, never asserted without a published entry behind it · pinned to MITRE ATT&CK v19.2 · compare on the matrix · Navigator layer (JSON)

Resource Development TA0042

T1583.003Acquire Infrastructure: Virtual Private Server×1

Adversaries may rent Virtual Private Servers (VPSs) that can be used during targeting. There exist a variety of cloud service providers that will sell virtual machines/containers as a service. By utilizing a VPS, adversaries can make it difficult to physically tie back operations to them. The use of cloud infrastructure can also make it easier for adversaries to rapidly provision, modify, and shut down their infrastructure.

Evidence: 2026-09-18/famoussparrow-sparrowocky-backdoor-latam-gov · ATT&CK page ↗

T1587.001Develop Capabilities: Malware×1

Adversaries may develop malware and malware components that can be used during targeting. Building malicious software can include the development of payloads, droppers, post-compromise tools, backdoors (including backdoored images), packers, C2 protocols, and the creation of infected removable media. Adversaries may develop malware to support their operations, creating a means for maintaining control of remote machines, evading defenses, and executing post-compromise behaviors.

Evidence: 2026-09-18/famoussparrow-sparrowocky-backdoor-latam-gov · ATT&CK page ↗

T1608.001Stage Capabilities: Upload Malware×1

Adversaries may upload malware to third-party or adversary controlled infrastructure to make it accessible during targeting. Malicious software can include payloads, droppers, post-compromise tools, backdoors, and a variety of other malicious content. Adversaries may upload malware to support their operations, such as making a payload available to a victim network to enable Ingress Tool Transfer by placing it on an Internet accessible web server.

Evidence: 2026-09-18/famoussparrow-sparrowocky-backdoor-latam-gov · ATT&CK page ↗

Initial Access TA0001

T1190Exploit Public-Facing Application×1

Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network. The weakness in the system can be a software bug, a temporary glitch, or a misconfiguration.

Evidence: 2026-09-18/famoussparrow-sparrowocky-backdoor-latam-gov · ATT&CK page ↗

Execution TA0002

T1059.003Command and Scripting Interpreter: Windows Command Shell×1

Adversaries may abuse the Windows command shell for execution. The Windows command shell (cmd) is the primary command prompt on Windows systems. The Windows command prompt can be used to control almost any aspect of a system, with various permission levels required for different subsets of commands. The command prompt can be invoked remotely via Remote Services such as SSH.

Evidence: 2026-09-18/famoussparrow-sparrowocky-backdoor-latam-gov · ATT&CK page ↗

T1106Native API×1

Adversaries may interact with the native OS application programming interface (API) to execute behaviors. Native APIs provide a controlled means of calling low-level OS services within the kernel, such as those involving hardware/devices, memory, and processes. These native APIs are leveraged by the OS during system boot (when other system components are not yet initialized) as well as carrying out tasks and requests during routine operations.

Evidence: 2026-09-18/famoussparrow-sparrowocky-backdoor-latam-gov · ATT&CK page ↗

T1559Inter-Process Communication×1

Adversaries may abuse inter-process communication (IPC) mechanisms for local code or command execution. IPC is typically used by processes to share data, communicate with each other, or synchronize execution. IPC is also commonly used to avoid situations such as deadlocks, which occurs when processes are stuck in a cyclic waiting pattern.

Evidence: 2026-09-18/famoussparrow-sparrowocky-backdoor-latam-gov · ATT&CK page ↗

T1569.002System Services: Service Execution×1

Adversaries may abuse the Windows service control manager to execute malicious commands or payloads. The Windows service control manager (<code>services.exe</code>) is an interface to manage and manipulate services. The service control manager is accessible to users via GUI components as well as system utilities such as <code>sc.exe</code> and Net.

Evidence: 2026-09-18/famoussparrow-sparrowocky-backdoor-latam-gov · ATT&CK page ↗

T1574.001Hijack Execution Flow: DLL×1

Adversaries may abuse dynamic-link library files (DLLs) in order to achieve persistence, escalate privileges, and evade defenses. DLLs are libraries that contain code and data that can be simultaneously utilized by multiple programs. While DLLs are not malicious by nature, they can be abused through mechanisms such as side-loading, hijacking search order, and phantom DLL hijacking.

Evidence: 2026-09-18/famoussparrow-sparrowocky-backdoor-latam-gov · ATT&CK page ↗

Persistence TA0003

T1543.003Create or Modify System Process: Windows Service×1

Adversaries may create or modify Windows services to repeatedly execute malicious payloads as part of persistence. When Windows boots up, it starts programs or applications called services that perform background system functions. Windows service configuration information, including the file path to the service's executable or recovery programs/commands, is stored in the Windows Registry.

Evidence: 2026-09-18/famoussparrow-sparrowocky-backdoor-latam-gov · ATT&CK page ↗

T1547.001Boot or Logon Autostart Execution: Registry Run Keys / Startup Folder×1

Adversaries may achieve persistence by adding a program to a startup folder or referencing it with a Registry run key. Adding an entry to the "run keys" in the Registry or startup folder will cause the program referenced to be executed when a user logs in. These programs will be executed under the context of the user and will have the account's associated permissions level.

Evidence: 2026-09-18/famoussparrow-sparrowocky-backdoor-latam-gov · ATT&CK page ↗

Privilege Escalation TA0004

T1134.002Access Token Manipulation: Create Process with Token×1

Adversaries may create a new process with an existing token to escalate privileges and bypass access controls. Processes can be created with the token and resulting security context of another user using features such as <code>CreateProcessWithTokenW</code> and <code>runas</code>.

Evidence: 2026-09-18/famoussparrow-sparrowocky-backdoor-latam-gov · ATT&CK page ↗

T1543.003Create or Modify System Process: Windows Service×1

Adversaries may create or modify Windows services to repeatedly execute malicious payloads as part of persistence. When Windows boots up, it starts programs or applications called services that perform background system functions. Windows service configuration information, including the file path to the service's executable or recovery programs/commands, is stored in the Windows Registry.

Evidence: 2026-09-18/famoussparrow-sparrowocky-backdoor-latam-gov · ATT&CK page ↗

T1547.001Boot or Logon Autostart Execution: Registry Run Keys / Startup Folder×1

Adversaries may achieve persistence by adding a program to a startup folder or referencing it with a Registry run key. Adding an entry to the "run keys" in the Registry or startup folder will cause the program referenced to be executed when a user logs in. These programs will be executed under the context of the user and will have the account's associated permissions level.

Evidence: 2026-09-18/famoussparrow-sparrowocky-backdoor-latam-gov · ATT&CK page ↗

Stealth TA0005

T1027.007Obfuscated Files or Information: Dynamic API Resolution×1

Adversaries may obfuscate then dynamically resolve API functions called by their malware in order to conceal malicious functionalities and impair defensive analysis. Malware commonly uses various Native API functions provided by the OS to perform various tasks such as those involving processes, files, and other system artifacts.

Evidence: 2026-09-18/famoussparrow-sparrowocky-backdoor-latam-gov · ATT&CK page ↗

T1036.001Masquerading: Invalid Code Signature×1

Adversaries may attempt to mimic features of valid code signatures to increase the chance of deceiving a user, analyst, or tool. Code signing provides a level of authenticity on a binary from the developer and a guarantee that the binary has not been tampered with. Adversaries can copy the metadata and signature information from a signed program, then use it as a template for an unsigned program. Files with invalid code signatures will fail digital signature validation checks, but they may appear more legitimate to users and security tools may improperly handle these files.

Evidence: 2026-09-18/famoussparrow-sparrowocky-backdoor-latam-gov · ATT&CK page ↗

T1036.004Masquerading: Masquerade Task or Service×1

Adversaries may attempt to manipulate the name of a task or service to make it appear legitimate or benign. Tasks/services executed by the Task Scheduler or systemd will typically be given a name and/or description. Windows services will have a service name as well as a display name. Many benign tasks and services exist that have commonly associated names. Adversaries may give tasks or services names that are similar or identical to those of legitimate ones.

Evidence: 2026-09-18/famoussparrow-sparrowocky-backdoor-latam-gov · ATT&CK page ↗

T1070.004Indicator Removal: File Deletion×1

Adversaries may delete files left behind by the actions of their intrusion activity. Malware, tools, or other non-native files dropped or created on a system by an adversary (ex: Ingress Tool Transfer) may leave traces to indicate to what was done within a network and how. Removal of these files can occur during an intrusion, or as part of a post-intrusion process to minimize the adversary's footprint.

Evidence: 2026-09-18/famoussparrow-sparrowocky-backdoor-latam-gov · ATT&CK page ↗

T1070.009Indicator Removal: Clear Persistence×1

Adversaries may clear artifacts associated with previously established persistence on a host system to remove evidence of their activity. This may involve various actions, such as removing services, deleting executables, Modify Registry, Plist File Modification, or other methods of cleanup to prevent defenders from collecting evidence of their persistent presence. Adversaries may also delete accounts previously created to maintain persistence (i.e. Create Account).

Evidence: 2026-09-18/famoussparrow-sparrowocky-backdoor-latam-gov · ATT&CK page ↗

T1134.002Access Token Manipulation: Create Process with Token×1

Adversaries may create a new process with an existing token to escalate privileges and bypass access controls. Processes can be created with the token and resulting security context of another user using features such as <code>CreateProcessWithTokenW</code> and <code>runas</code>.

Evidence: 2026-09-18/famoussparrow-sparrowocky-backdoor-latam-gov · ATT&CK page ↗

T1140Deobfuscate/Decode Files or Information×1

Adversaries may use Obfuscated Files or Information to hide artifacts of an intrusion from analysis. They may require separate mechanisms to decode or deobfuscate that information depending on how they intend to use it. Methods for doing that include built-in functionality of malware or by using utilities present on the system.

Evidence: 2026-09-18/famoussparrow-sparrowocky-backdoor-latam-gov · ATT&CK page ↗

T1480.002Execution Guardrails: Mutual Exclusion×1

Adversaries may constrain execution or actions based on the presence of a mutex associated with malware. A mutex is a locking mechanism used to synchronize access to a resource. Only one thread or process can acquire a mutex at a given time.

Evidence: 2026-09-18/famoussparrow-sparrowocky-backdoor-latam-gov · ATT&CK page ↗

T1564.010Hide Artifacts: Process Argument Spoofing×1

Adversaries may attempt to hide process command-line arguments by overwriting process memory. Process command-line arguments are stored in the process environment block (PEB), a data structure used by Windows to store various information about/used by a process. The PEB includes the process command-line arguments that are referenced when executing the process. When a process is created, defensive tools/sensors that monitor process creations may retrieve the process arguments from the PEB.

Evidence: 2026-09-18/famoussparrow-sparrowocky-backdoor-latam-gov · ATT&CK page ↗

T1574.001Hijack Execution Flow: DLL×1

Adversaries may abuse dynamic-link library files (DLLs) in order to achieve persistence, escalate privileges, and evade defenses. DLLs are libraries that contain code and data that can be simultaneously utilized by multiple programs. While DLLs are not malicious by nature, they can be abused through mechanisms such as side-loading, hijacking search order, and phantom DLL hijacking.

Evidence: 2026-09-18/famoussparrow-sparrowocky-backdoor-latam-gov · ATT&CK page ↗

T1620Reflective Code Loading×1

Adversaries may reflectively load code into a process in order to conceal the execution of malicious payloads. Reflective loading involves allocating then executing payloads directly within the memory of the process, vice creating a thread or process backed by a file path on disk (e.g., Shared Modules).

Evidence: 2026-09-18/famoussparrow-sparrowocky-backdoor-latam-gov · ATT&CK page ↗

Discovery TA0007

T1033System Owner/User Discovery×1

Adversaries may attempt to identify the primary user, currently logged in user, set of users that commonly uses a system, or whether a user is actively using the system. They may do this, for example, by retrieving account usernames or by using OS Credential Dumping. The information may be collected in a number of different ways using other Discovery techniques, because user and username details are prevalent throughout a system and include running process ownership, file/directory ownership, session information, and system logs. Adversaries may use the information from System Owner/User Discovery during automated discovery to shape follow-on behaviors, including whether or not the adversary fully infects the target and/or attempts specific actions.

Evidence: 2026-09-18/famoussparrow-sparrowocky-backdoor-latam-gov · ATT&CK page ↗

T1082System Information Discovery×1

An adversary may attempt to get detailed information about the operating system and hardware, including version, patches, hotfixes, service packs, and architecture. Adversaries may use this information to shape follow-on behaviors, including whether or not the adversary fully infects the target and/or attempts specific actions. This behavior is distinct from Local Storage Discovery which is an adversary's discovery of local drive, disks and/or volumes.

Evidence: 2026-09-18/famoussparrow-sparrowocky-backdoor-latam-gov · ATT&CK page ↗

T1083File and Directory Discovery×1

Adversaries may enumerate files and directories or may search in specific locations of a host or network share for certain information within a file system. Adversaries may use the information from File and Directory Discovery during automated discovery to shape follow-on behaviors, including whether or not the adversary fully infects the target and/or attempts specific actions.

Evidence: 2026-09-18/famoussparrow-sparrowocky-backdoor-latam-gov · ATT&CK page ↗

T1120Peripheral Device Discovery×1

Adversaries may attempt to gather information about attached peripheral devices and components connected to a computer system. Peripheral devices could include auxiliary resources that support a variety of functionalities such as keyboards, printers, cameras, smart card readers, or removable storage. The information may be used to enhance their awareness of the system and network environment or may be used for further actions.

Evidence: 2026-09-18/famoussparrow-sparrowocky-backdoor-latam-gov · ATT&CK page ↗

T1680Local Storage Discovery×1

Adversaries may enumerate local drives, disks, and/or volumes and their attributes like total or free space and volume serial number. This can be done to prepare for ransomware-related encryption, to perform Lateral Movement, or as a precursor to Direct Volume Access.

Evidence: 2026-09-18/famoussparrow-sparrowocky-backdoor-latam-gov · ATT&CK page ↗

Collection TA0009

T1005Data from Local System×1

Adversaries may search local system sources, such as file systems, configuration files, local databases, virtual machine files, or process memory, to find files of interest and sensitive data prior to Exfiltration.

Evidence: 2026-09-18/famoussparrow-sparrowocky-backdoor-latam-gov · ATT&CK page ↗

T1113Screen Capture×1

Adversaries may attempt to take screen captures of the desktop to gather information over the course of an operation. Screen capturing functionality may be included as a feature of a remote access tool used in post-compromise operations. Taking a screenshot is also typically possible through native utilities or API calls, such as <code>CopyFromScreen</code>, <code>xwd</code>, or <code>screencapture</code>.

Evidence: 2026-09-18/famoussparrow-sparrowocky-backdoor-latam-gov · ATT&CK page ↗

Command and Control TA0011

T1090.001Proxy: Internal Proxy×1

Adversaries may use an internal proxy to direct command and control traffic between two or more systems in a compromised environment. Many tools exist that enable traffic redirection through proxies or port redirection, including HTRAN, ZXProxy, and ZXPortMap. Adversaries use internal proxies to manage command and control communications inside a compromised environment, to reduce the number of simultaneous outbound network connections, to provide resiliency in the face of connection loss, or to ride over existing trusted communications paths between infected systems to avoid suspicion. Internal proxy connections may use common peer-to-peer (p2p) networking protocols, such as SMB, to better blend in with the environment.

Evidence: 2026-09-18/famoussparrow-sparrowocky-backdoor-latam-gov · ATT&CK page ↗

T1090.002Proxy: External Proxy×1

Adversaries may use an external proxy to act as an intermediary for network communications to a command and control server to avoid direct connections to their infrastructure. Many tools exist that enable traffic redirection through proxies or port redirection, including HTRAN, ZXProxy, and ZXPortMap. Adversaries use these types of proxies to manage command and control communications, to provide resiliency in the face of connection loss, or to ride over existing trusted communications paths to avoid suspicion.

Evidence: 2026-09-18/famoussparrow-sparrowocky-backdoor-latam-gov · ATT&CK page ↗

T1095Non-Application Layer Protocol×1

Adversaries may use an OSI non-application layer protocol for communication between host and C2 server or among infected hosts within a network. The list of possible protocols is extensive. Specific examples include use of network layer protocols, such as the Internet Control Message Protocol (ICMP), transport layer protocols, such as the User Datagram Protocol (UDP), session layer protocols, such as Socket Secure (SOCKS), as well as redirected/tunneled protocols, such as Serial over LAN (SOL).

Evidence: 2026-09-18/famoussparrow-sparrowocky-backdoor-latam-gov · ATT&CK page ↗

T1573.001Encrypted Channel: Symmetric Cryptography×1

Adversaries may employ a known symmetric encryption algorithm to conceal command and control traffic rather than relying on any inherent protections provided by a communication protocol. Symmetric encryption algorithms use the same key for plaintext encryption and ciphertext decryption. Common symmetric encryption algorithms include AES, DES, 3DES, Blowfish, and RC4.

Evidence: 2026-09-18/famoussparrow-sparrowocky-backdoor-latam-gov · ATT&CK page ↗

T1573.002Encrypted Channel: Asymmetric Cryptography×1

Adversaries may employ a known asymmetric encryption algorithm to conceal command and control traffic rather than relying on any inherent protections provided by a communication protocol. Asymmetric cryptography, also known as public key cryptography, uses a keypair per party: one public that can be freely distributed, and one private. Due to how the keys are generated, the sender encrypts data with the receiver’s public key and the receiver decrypts the data with their private key. This ensures that only the intended recipient can read the encrypted data. Common public key encryption algorithms include RSA and ElGamal.

Evidence: 2026-09-18/famoussparrow-sparrowocky-backdoor-latam-gov · ATT&CK page ↗

Exfiltration TA0010

T1041Exfiltration Over C2 Channel×1

Adversaries may steal data by exfiltrating it over an existing command and control channel. Stolen data is encoded into the normal communications channel using the same protocol as command and control communications.

Evidence: 2026-09-18/famoussparrow-sparrowocky-backdoor-latam-gov · ATT&CK page ↗

Story timeline

  1. 2026-09-18FamousSparrow retires SparrowDoor for SparroWocky, a modular backdoor with BOF-loading and call-stack spoofing, deployed almost exclusively against Latin American governments
    active-threatsESET: a China-aligned actor's new backdoor forges call stacks with legitimate kernel32.dll gadgets so its hooked API calls look native

Where this entity is cited

  • active-threats1

Source distribution

  • welivesecurity.com1 (100%)

Co-occurring entities

Derived: referenced by the same focused operational entries (weekly summaries and report roundups don't count); ×N counts the shared entries.

Entries about SparroWocky (1)

2026-09-18 · view entry permalink →

NOTABLENATOB2

FamousSparrow retires SparrowDoor for SparroWocky, a modular backdoor with BOF-loading and call-stack spoofing, deployed almost exclusively against Latin American governments

ESET documents FamousSparrow's shift to a new flagship backdoor, SparroWocky, replacing SparrowDoor as the group's main implant since August 2025 (ESET, 2026-09-17). From mid-2025 into 2026, 90% of FamousSparrow's observed targets were in Latin America (Argentina, Ecuador, Guatemala, Honduras, Panama, Peru, Puerto Rico and Venezuela) with government entities named among the targets, an unusually sustained single-region focus for a China-aligned group ESET otherwise tracks globally; ESET assesses the focus likely reflects Chinese state interest in monitoring regional government reactions to renewed US engagement, citing a Panamanian port-concession dispute as a specific target-motive match (ESET, 2026-09-17). SparroWocky deploys via a "trident loader": a legitimate executable, a side-loading DLL with a patched .text-section entry point that keeps the impersonated module's export table and metadata intact, and an RC4-encrypted .dat payload whose decrypted PE has its MZ/PE header bytes stripped before being reflectively mapped into memory. The backdoor incorporates Mbed TLS for its C2 channel and MinHook for API hooking, and runs a modified TrustedSec COFF loader that executes Cobalt Strike, Brute Ratel, Metasploit and Sliver-compatible Beacon Object Files, redirecting BOF-imported-symbol calls through a stack-spoofing subroutine. Its anti-analysis techniques include a SilentMoonwalk-style call-stack forger that uses JOP/ROP gadgets inside legitimate kernel32.dll so hooked API calls appear to originate from RtlUserThreadStart or BaseThreadInitThunk, and a MinHook-based CreateThread hook that reports the benign-looking AnimateWindow as the thread's start address; for dynamically loaded PE payloads, the backdoor also forges a fake LDR_DATA_TABLE_ENTRY structure in the PEB_LDR_DATA doubly linked list Windows uses to track loaded modules, a list security products routinely monitor. Persistence is operator-configurable via a Windows service or a registry Run key. ESET attributes SparroWocky to FamousSparrow with high confidence, since early attacks show the FamousSparrow-exclusive SparrowDoor deploying the new backdoor directly.

Triage: call-stack forgery targeting RtlUserThreadStart or BaseThreadInitThunk is not something a legitimate application produces; a stack walk that resolves cleanly to one of those two entry points via JOP/ROP gadgets in kernel32.dll, rather than a normal thread-creation call chain, is the discriminator ESET's own analysis supports.

We believe that this focus is not coincidental and likely reflects China's reaction to various recent US initiatives in the region.

Based on our investigation, we attribute the latest campaign and the SparroWocky backdoor to FamousSparrow with high confidence, since in some of the first attacks involving this backdoor, SparroWocky was deployed by the FamousSparrow-exclusive SparrowDoor.

ESET (WeLiveSecurity) 2026-09-17
threat18 Sep 04:56Zsingle-sourceOpen finding ↗