TernDoor
malware · malware:terndoor
Backdoor whose execution chain loads a Windows driver, assessed by Bitdefender in the second wave of FamousSparrow's intrusion of an Azerbaijani energy operator and documented by Cisco Talos with UAT-9244 (Bitdefender, 2026-05-13).
Defender insights
What each entry about TernDoor tells a defender to do, newest first.
Relationships explore in graph
Typed, source-stated connections from the entity registry; each edge cites the entry whose reporting establishes it.
used by
Story timeline
Hunting pivots
ATT&CK techniques (17 across 8 tactics)
17 techniques observed across 1 entry about this entity, derived from entry metadata and body evidence, never asserted without a published entry behind it · pinned to MITRE ATT&CK v20.0 · compare on the matrix · Navigator layer (JSON)
- Initial AccessValid Accounts: Domain Accounts · Exploit Public-Facing Application
- ExecutionCommand and Scripting Interpreter: PowerShell · System Services: Service Execution · Hijack Execution Flow: DLL
- PersistenceValid Accounts: Domain Accounts · Modify Registry · Server Software Component: Web Shell · Create or Modify System Process: Windows Service
- Privilege EscalationProcess Injection · Valid Accounts: Domain Accounts · Create or Modify System Process: Windows Service
- StealthRootkit · Obfuscated Files or Information · Masquerading: Match Legitimate Resource Name or Location · Process Injection · Valid Accounts: Domain Accounts · Deobfuscate/Decode Files or Information · Hijack Execution Flow: DLL
- Defense ImpairmentModify Registry
- Lateral MovementRemote Services: Remote Desktop Protocol · Remote Services: SMB/Windows Admin Shares
- Command and ControlApplication Layer Protocol: Web Protocols · Ingress Tool Transfer
Initial Access TA0001
T1078.002Valid Accounts: Domain Accounts×1
Adversaries may obtain and abuse credentials of a domain account as a means of gaining Initial Access, Persistence, Privilege Escalation, or Defense Evasion. Domain accounts are those managed by Active Directory Domain Services where access and permissions are configured across systems and services that are part of that domain. Domain accounts can cover users, administrators, and services.
Evidence: 2026-05-14/famoussparrow-three-wave-intrusion-of-an-azerbaijani-energy · ATT&CK page ↗
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: 2026-05-14/famoussparrow-three-wave-intrusion-of-an-azerbaijani-energy · ATT&CK page ↗
Execution TA0002
T1059.001Command and Scripting Interpreter: PowerShell×1
Adversaries may abuse PowerShell commands and scripts for execution. PowerShell is a powerful interactive command-line interface and scripting environment included in the Windows operating system. PowerShell can also be installed on Linux and macOS. Adversaries can use PowerShell to perform a number of actions, including discovery of information and execution of code. Examples include the <code>Start-Process</code> cmdlet which can be used to run an executable and the <code>Invoke-Command</code> cmdlet which runs a command locally or on a remote computer (though administrator permissions are required to use PowerShell to connect to remote systems).
Evidence: 2026-05-14/famoussparrow-three-wave-intrusion-of-an-azerbaijani-energy · 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: 2026-05-14/famoussparrow-three-wave-intrusion-of-an-azerbaijani-energy · 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: 2026-05-14/famoussparrow-three-wave-intrusion-of-an-azerbaijani-energy · ATT&CK page ↗
Persistence TA0003
T1078.002Valid Accounts: Domain Accounts×1
Adversaries may obtain and abuse credentials of a domain account as a means of gaining Initial Access, Persistence, Privilege Escalation, or Defense Evasion. Domain accounts are those managed by Active Directory Domain Services where access and permissions are configured across systems and services that are part of that domain. Domain accounts can cover users, administrators, and services.
Evidence: 2026-05-14/famoussparrow-three-wave-intrusion-of-an-azerbaijani-energy · ATT&CK page ↗
T1112Modify Registry×1
Adversaries may interact with the Windows Registry as part of a variety of other techniques to aid in defense evasion, persistence, and execution.
Evidence: 2026-05-14/famoussparrow-three-wave-intrusion-of-an-azerbaijani-energy · ATT&CK page ↗
T1505.003Server Software Component: Web Shell×1
Adversaries may backdoor web servers with web shells to establish persistent access to systems. A Web shell is a Web script that is placed on an openly accessible Web server to allow an adversary to access the Web server as a gateway into a network. A Web shell may provide a set of functions to execute or a command-line interface on the system that hosts the Web server.
Evidence: 2026-05-14/famoussparrow-three-wave-intrusion-of-an-azerbaijani-energy · 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: 2026-05-14/famoussparrow-three-wave-intrusion-of-an-azerbaijani-energy · ATT&CK page ↗
Privilege Escalation TA0004
T1055Process Injection×1
Adversaries may inject code into processes in order to evade process-based defenses as well as possibly elevate privileges. Process injection is a method of executing arbitrary code in the address space of a separate live process. Running code in the context of another process may allow access to the process's memory, system/network resources, and possibly elevated privileges. Execution via process injection may also evade detection from security products since the execution is masked under a legitimate process.
Evidence: 2026-05-14/famoussparrow-three-wave-intrusion-of-an-azerbaijani-energy · ATT&CK page ↗
T1078.002Valid Accounts: Domain Accounts×1
Adversaries may obtain and abuse credentials of a domain account as a means of gaining Initial Access, Persistence, Privilege Escalation, or Defense Evasion. Domain accounts are those managed by Active Directory Domain Services where access and permissions are configured across systems and services that are part of that domain. Domain accounts can cover users, administrators, and services.
Evidence: 2026-05-14/famoussparrow-three-wave-intrusion-of-an-azerbaijani-energy · 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: 2026-05-14/famoussparrow-three-wave-intrusion-of-an-azerbaijani-energy · ATT&CK page ↗
Stealth TA0005
T1014Rootkit×1
Adversaries may use rootkits to hide the presence of programs, files, network connections, services, drivers, and other system components. Rootkits are programs that hide the existence of malware by intercepting/hooking and modifying operating system API calls that supply system information.
Evidence: 2026-05-14/famoussparrow-three-wave-intrusion-of-an-azerbaijani-energy · ATT&CK page ↗
T1027Obfuscated Files or Information×1
Adversaries may attempt to make an executable or file difficult to discover or analyze by encrypting, encoding, or otherwise obfuscating its contents on the system or in transit. This is common behavior that can be used across different platforms and the network to evade defenses.
Evidence: 2026-05-14/famoussparrow-three-wave-intrusion-of-an-azerbaijani-energy · ATT&CK page ↗
T1036.005Masquerading: Match Legitimate Resource Name or Location×1
Adversaries may match or approximate the name or location of legitimate files, Registry keys, or other resources when naming/placing them. This is done for the sake of evading defenses and observation.
Evidence: 2026-05-14/famoussparrow-three-wave-intrusion-of-an-azerbaijani-energy · ATT&CK page ↗
T1055Process Injection×1
Adversaries may inject code into processes in order to evade process-based defenses as well as possibly elevate privileges. Process injection is a method of executing arbitrary code in the address space of a separate live process. Running code in the context of another process may allow access to the process's memory, system/network resources, and possibly elevated privileges. Execution via process injection may also evade detection from security products since the execution is masked under a legitimate process.
Evidence: 2026-05-14/famoussparrow-three-wave-intrusion-of-an-azerbaijani-energy · ATT&CK page ↗
T1078.002Valid Accounts: Domain Accounts×1
Adversaries may obtain and abuse credentials of a domain account as a means of gaining Initial Access, Persistence, Privilege Escalation, or Defense Evasion. Domain accounts are those managed by Active Directory Domain Services where access and permissions are configured across systems and services that are part of that domain. Domain accounts can cover users, administrators, and services.
Evidence: 2026-05-14/famoussparrow-three-wave-intrusion-of-an-azerbaijani-energy · 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: 2026-05-14/famoussparrow-three-wave-intrusion-of-an-azerbaijani-energy · 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: 2026-05-14/famoussparrow-three-wave-intrusion-of-an-azerbaijani-energy · ATT&CK page ↗
Defense Impairment TA0112
T1112Modify Registry×1
Adversaries may interact with the Windows Registry as part of a variety of other techniques to aid in defense evasion, persistence, and execution.
Evidence: 2026-05-14/famoussparrow-three-wave-intrusion-of-an-azerbaijani-energy · ATT&CK page ↗
Lateral Movement TA0008
T1021.001Remote Services: Remote Desktop Protocol×1
Adversaries may use Valid Accounts to log into a computer using the Remote Desktop Protocol (RDP). The adversary may then perform actions as the logged-on user.
Evidence: 2026-05-14/famoussparrow-three-wave-intrusion-of-an-azerbaijani-energy · ATT&CK page ↗
T1021.002Remote Services: SMB/Windows Admin Shares×1
Adversaries may use Valid Accounts to interact with a remote network share using Server Message Block (SMB). The adversary may then perform actions as the logged-on user.
Evidence: 2026-05-14/famoussparrow-three-wave-intrusion-of-an-azerbaijani-energy · ATT&CK page ↗
Command and Control TA0011
T1071.001Application Layer Protocol: Web Protocols×1
Adversaries may communicate using application layer protocols associated with web traffic to avoid detection/network filtering by blending in with existing traffic. Commands to the remote system, and often the results of those commands, will be embedded within the protocol traffic between the client and server.
Evidence: 2026-05-14/famoussparrow-three-wave-intrusion-of-an-azerbaijani-energy · ATT&CK page ↗
T1105Ingress Tool Transfer×1
Adversaries may transfer tools or other files from an external system into a compromised environment. Tools or files may be copied from an external adversary-controlled system to the victim network through the command and control channel or through alternate protocols such as ftp. Once present, adversaries may also transfer/spread tools between victim devices within a compromised environment (i.e. Lateral Tool Transfer).
Evidence: 2026-05-14/famoussparrow-three-wave-intrusion-of-an-azerbaijani-energy · ATT&CK page ↗
Entries about TernDoor (1)
Co-occurring entities
Derived: referenced by the same focused operational entries (weekly summaries and report roundups don't count); ×N counts the shared entries.
- Deed RAT×1
- FamousSparrow×1
- FamousSparrow Azerbaijan intrusion×1
- Microsoft Exchange Server×1
- Microsoft Exchange Server PowerShell remoting deserialization RCE (ProxyNotShell), cited as initial-access vector in 2026-05-14 FamousSparrow deep dive; chained with CVE-2022-41040×1
- Microsoft Exchange Server SSRF (ProxyNotShell), cited as initial-access vector in 2026-05-14 FamousSparrow deep dive; chained with CVE-2022-41082×1
- Mofu Loader×1
Where this entity is cited
Source distribution
- msrc.microsoft.com2 (33%)
- bitdefender.com1 (17%)
- cisa.gov1 (17%)
- microsoft.github.io1 (17%)
- thehackernews.com1 (17%)
All cited sources (6)
- bitdefender.comBitdefenderhttps://www.bitdefender.com/en-us/blog/businessinsights/famoussparrow-apt-targets-azerbaijani-oil-gas-industry
- cisa.govCISA KEV cataloghttps://www.cisa.gov/sites/default/files/feeds/known_exploited_vulnerabilities.json
- microsoft.github.ioMicrosoft CSS-Exchange (HealthChecker)https://microsoft.github.io/CSS-Exchange/Diagnostics/HealthChecker/
- msrc.microsoft.comMicrosoft Security Response Centerhttps://msrc.microsoft.com/update-guide/vulnerability/CVE-2022-41040
- msrc.microsoft.comMicrosoft Security Response Centerhttps://msrc.microsoft.com/update-guide/vulnerability/CVE-2022-41082
- thehackernews.comThe Hacker Newshttps://thehackernews.com/2026/05/azerbaijani-energy-firm-hit-by-repeated.html