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MITRE ATT&CK® Technique

T1040: Network Sniffing

Adversaries may passively sniff network traffic to capture information about an environment, including authentication material passed over the network. Network sniffing refers to using the network interface on a system to monitor or capture information sent over a wired or wireless connection. An adversary may place a network interface into promiscuous mode to passively access data in transit over the network, or use span ports to capture a larger amount of data.

Data captured via this technique may include user credentials, especially those sent over an insecure, unencrypted protocol. Techniques for name service resolution poisoning, such as Name Resolution Poisoning and SMB Relay, can also be used to capture credentials to websites, proxies, and internal systems by redirecting traffic to an adversary.

Network sniffing may reveal configuration details, such as running services, version numbers, and other network characteristics (e.g. IP addresses, hostnames, VLAN IDs) necessary for subsequent Lateral Movement and/or Stealth activities. Adversaries may likely also utilize network sniffing during Adversary-in-the-Middle (AiTM) to passively gain additional knowledge about the environment.

In cloud-based environments, adversaries may still be able to use traffic mirroring services to sniff network traffic from virtual machines. For example, AWS Traffic Mirroring, GCP Packet Mirroring, and Azure vTap allow users to define specified instances to collect traffic from and specified targets to send collected traffic to.[1][2][3] Often, much of this traffic will be in cleartext due to the use of TLS termination at the load balancer level to reduce the strain of encrypting and decrypting traffic.[4][5] The adversary can then use exfiltration techniques such as Transfer Data to Cloud Account in order to access the sniffed traffic.[4]

On network devices, adversaries may perform network captures using Network Device CLI commands such as `monitor capture`.[6][7]

EnterpriseT1040TechniqueObject v1.7 Modified
Glexia's Take

Analyst context for executives and security teams

Analyst confidence Medium

Network Sniffing matters because it can turn ordinary network access into credential theft and environment discovery. If traffic is unencrypted, mirrored, relayed, or visible from a compromised host, cloud workload, or network device, an adversary may capture authentication material and internal details that support later movement or stealth. For leaders, this is a control validation issue: encryption, segmentation, privileged access to packet-capture features, and monitoring of traffic mirroring or capture activity determine whether this technique is a manageable risk or a blind spot.

Executive priority

Prioritize this technique where sensitive authentication or operational traffic crosses shared networks, cloud environments, load-balanced architectures with TLS termination, or managed network devices. It is especially relevant to business continuity and cyber-physical risk because ATT&CK links it to campaigns involving electric power and network infrastructure targeting. Executive questions should include: where is traffic still cleartext, who can enable packet capture or cloud traffic mirroring, are network device administrative actions logged, and can the SOC distinguish approved troubleshooting captures from suspicious collection?

Technical view

ATT&CK lists Network Sniffing under credential access and discovery across IaaS, Linux, macOS, Windows, and network devices. Defensive validation should focus on passive capture opportunities: interfaces entering promiscuous mode, span or mirror port usage, cloud traffic mirroring or virtual TAP configuration, and network device CLI capture commands such as monitor capture. Relationship context also points defenders toward identity and network controls: User Account Management, Network Segmentation, Multi-factor Authentication, and Encrypt Sensitive Information. Because ATT&CK does not provide official detection text for this object, SOC teams should rely on the related detection strategy DET0314 where available and validate it against local telemetry.

Likely telemetry

  • Cloud control-plane logs for creation, modification, and deletion of traffic mirroring, packet mirroring, or virtual TAP sessions
  • Network device administrative logs and command history for packet capture, monitor capture, span, or mirror configuration changes
  • Endpoint telemetry showing packet capture tools, raw socket use, or network interfaces placed in promiscuous mode on Linux, macOS, or Windows
  • Network flow records and segmentation policy logs showing unusual collection paths or traffic sent to unexpected capture targets
  • Authentication and directory telemetry for credential use that may follow exposure over insecure protocols

Detection direction

  • Inventory approved packet capture, span, mirror, and cloud traffic mirroring use cases so detections can distinguish authorized troubleshooting from suspicious collection.
  • Alert on new or modified mirroring sessions, unexpected capture targets, and capture activity initiated by accounts that do not normally administer network or cloud telemetry features.
  • Monitor network device CLI activity for embedded packet capture commands and correlate with change tickets or maintenance windows.
  • Tune endpoint detections for promiscuous mode or packet capture behavior carefully, since legitimate administrators and monitoring tools may generate similar events.
  • Use relationship context with Name Resolution Poisoning and SMB Relay and Adversary-in-the-Middle to investigate whether sniffing is part of a broader credential capture or relay pattern.

Mitigation priorities

  • Reduce value of captured traffic first: encrypt sensitive information in transit and identify cleartext segments created by TLS termination or legacy protocols.
  • Restrict who can configure packet capture, span ports, cloud traffic mirroring, virtual TAPs, and network device capture features using least privilege and user account management.
  • Apply network segmentation so a compromised system or device cannot observe unnecessary traffic from critical systems or sensitive zones.
  • Use multi-factor authentication for critical systems so captured passwords alone are less useful, while recognizing MFA does not remove the need to protect traffic and sessions.
  • Review administrative change control and logging requirements for cloud networking and network devices to support compliance evidence and incident reconstruction.
Analyst notes and limits

The supplied ATT&CK object has no official detection field, but it includes a related detection strategy, DET0314, and several mitigation relationships. The relationship set shows use by multiple groups, campaigns, and software, including activity involving power-grid and network-infrastructure contexts, which supports prioritizing this technique for organizations with critical infrastructure, telecommunications, cloud, or network-device exposure. Local architecture determines materiality: the key questions are where traffic is visible, whether it is encrypted, and who can enable capture or mirroring.

This take uses only the supplied ATT&CK fields and relationships. It does not assert current exploitation, customer exposure, or detection coverage. The object describes platforms and examples, but local telemetry, cloud provider configuration, network-device logging, and encryption design must be assessed before making risk or coverage claims.

Official MITRE ATT&CK definition

Network Sniffing

Adversaries may passively sniff network traffic to capture information about an environment, including authentication material passed over the network. Network sniffing refers to using the network interface on a system to monitor or capture information sent over a wired or wireless connection. An adversary may place a network interface into promiscuous mode to passively access data in transit over the network, or use span ports to capture a larger amount of data.

Data captured via this technique may include user credentials, especially those sent over an insecure, unencrypted protocol. Techniques for name service resolution poisoning, such as Name Resolution Poisoning and SMB Relay, can also be used to capture credentials to websites, proxies, and internal systems by redirecting traffic to an adversary.

Network sniffing may reveal configuration details, such as running services, version numbers, and other network characteristics (e.g. IP addresses, hostnames, VLAN IDs) necessary for subsequent Lateral Movement and/or Stealth activities. Adversaries may likely also utilize network sniffing during Adversary-in-the-Middle (AiTM) to passively gain additional knowledge about the environment.

In cloud-based environments, adversaries may still be able to use traffic mirroring services to sniff network traffic from virtual machines. For example, AWS Traffic Mirroring, GCP Packet Mirroring, and Azure vTap allow users to define specified instances to collect traffic from and specified targets to send collected traffic to.[1][2][3] Often, much of this traffic will be in cleartext due to the use of TLS termination at the load balancer level to reduce the strain of encrypting and decrypting traffic.[4][5] The adversary can then use exfiltration techniques such as Transfer Data to Cloud Account in order to access the sniffed traffic.[4]

On network devices, adversaries may perform network captures using Network Device CLI commands such as `monitor capture`.[6][7]

View the same entry on attack.mitre.org (MITRE-hosted reference; in-page links above use the Glexia ATT&CK library.)

Glexia analysis

How security teams should use this page

Treat this object as behavior context, not an attribution claim. Validate the related groups, software, data sources, and mitigations against official ATT&CK relationships and your own telemetry before making control-coverage decisions.

Associated objects

Groups, software, and campaigns

Group Enterprise

G0034: Sandworm Team

Sandworm Team is a destructive threat group that has been attributed to Russia's General Staff Main Intelligence Directorate (GRU) Main Center for Special Technologies (GTsST) military unit 74455.[1][2] This group has been active since at least 2009.[3][4][5][6]

In October 2020, the US indicted six GRU Unit 74455 officers associated with Sandworm Team for the following cyber operations: the 2015 and 2016 attacks against Ukrainian electrical companies and government organizations, the 2017 worldwide NotPetya attack, targeting of the 2017 French presidential campaign, the 2018 Olympic Destroyer attack against the Winter Olympic Games, the 2018 operation against the Organisation for the Prohibition of Chemical Weapons, and attacks against the country of Georgia in 2018 and 2019.[1][2] Some of these were conducted with the assistance of GRU Unit 26165, which is also referred to as APT28.[7]

Group Enterprise

G0094: Kimsuky

Kimsuky is a Democratic People's Republic of Korea (DPRK)-based cyber espionage group that has been active since at least 2012. The group initially targeted South Korean government agencies, think tanks, and subject-matter experts in various fields. Its operations expanded to include the United Nations and organizations in the government, education, business services, and manufacturing sectors across the United States, Japan, Russia, and Europe. Kimsuky has focused collection on foreign policy and national security issues tied to the Korean Peninsula, nuclear policy, and sanctions. Kimsuky operations have overlapped with those of other North Korean state-sponsored cyber espionage actors as a result of ad hoc collaborations or other limited resource sharing.[1][2][3][4][5][6]

Kimsuky was assessed to be responsible for the 2014 Korea Hydro & Nuclear Power Co. compromise; other notable campaigns include Operation STOLEN PENCIL (2018), Operation Kabar Cobra (2019), and Operation Smoke Screen (2019).[7][8][9] In 2023, Kimsuky was observed using commercial large language models (LLMs) to assist with vulnerability research, scripting, social engineering and reconnaissance.[10]

DPRK threat actor cluster boundaries overlap in open source reporting, with some security researchers consolidating all attributed North Korean state-sponsored cyber activity under Lazarus Group, rather than tracking operationally distinct subgroups.

Group Enterprise

G1047: Velvet Ant

Velvet Ant is a threat actor operating since at least 2021. Velvet Ant is associated with complex persistence mechanisms, the targeting of network devices and appliances during operations, and the use of zero day exploits.[1][2]

Group Enterprise

G1045: Salt Typhoon

Salt Typhoon is a People's Republic of China (PRC) state-backed actor that has been active since at least 2019 and responsible for numerous compromises of network infrastructure at major U.S. telecommunication and internet service providers (ISP).[1][2]

Group Enterprise

G0064: APT33

APT33 is a suspected Iranian threat group that has carried out operations since at least 2013. The group has targeted organizations across multiple industries in the United States, Saudi Arabia, and South Korea, with a particular interest in the aviation and energy sectors.[1][2]

Group Enterprise

G1048: UNC3886

UNC3886 is a China-nexus cyberespionage group that has been active since at least 2022, targeting defense, technology, and telecommunication organizations located in the United States and the Asia-Pacific-Japan (APJ) regions. UNC3886 has displayed a deep understanding of edge devices and virtualization technologies through the exploitation of zero-day vulnerabilities and the use of novel malware families and utilities.[1][2]

Group Enterprise

G0105: DarkVishnya

DarkVishnya is a financially motivated threat actor targeting financial institutions in Eastern Europe. In 2017-2018 the group attacked at least 8 banks in this region.[1]

Group Enterprise

G0007: APT28

APT28 is a threat group that has been attributed to Russia's General Staff Main Intelligence Directorate (GRU) 85th Main Special Service Center (GTsSS) military unit 26165.[1][2] This group has been active since at least 2004.[3][4][5][6][7][8][9][10][11][12][13]

APT28 reportedly compromised the Hillary Clinton campaign, the Democratic National Committee, and the Democratic Congressional Campaign Committee in 2016 in an attempt to interfere with the U.S. presidential election.[5] In 2018, the US indicted five GRU Unit 26165 officers associated with APT28 for cyber operations (including close-access operations) conducted between 2014 and 2018 against the World Anti-Doping Agency (WADA), the US Anti-Doping Agency, a US nuclear facility, the Organization for the Prohibition of Chemical Weapons (OPCW), the Spiez Swiss Chemicals Laboratory, and other organizations.[14] Some of these were conducted with the assistance of GRU Unit 74455, which is also referred to as Sandworm Team.

Tool Enterprise

S0357: Impacket

Impacket is an open source collection of modules written in Python for programmatically constructing and manipulating network protocols. Impacket contains several tools for remote service execution, Kerberos manipulation, Windows credential dumping, packet sniffing, and relay attacks.[1]

LinuxmacOSWindows
Malware Enterprise

S0443: MESSAGETAP

MESSAGETAP is a data mining malware family deployed by APT41 into telecommunications networks to monitor and save SMS traffic from specific phone numbers, IMSI numbers, or that contain specific keywords. [1]

Linux
Malware Enterprise

S1206: JumbledPath

JumbledPath is a custom-built utility written in GO that has been used by Salt Typhoon since at least 2024 for packet capture on remote Cisco devices. JumbledPath is compiled as an ELF binary using x86-64 architecture which makes it potentially useable across Linux operating systems and network devices from multiple vendors.[1]

Network Devices
Malware Enterprise

S0661: FoggyWeb

FoggyWeb is a passive and highly-targeted backdoor capable of remotely exfiltrating sensitive information from a compromised Active Directory Federated Services (AD FS) server. It has been used by APT29 since at least early April 2021.[1]

Windows
Tool Enterprise

S0363: Empire

Empire is an open-source, cross-platform remote administration and post-exploitation framework that is publicly available on GitHub. While the tool itself is primarily written in Python, the post-exploitation agents are written in pure PowerShell for Windows and Python for Linux/macOS. Empire was one of five tools singled out by a joint report on public hacking tools being widely used by adversaries.[1][2][3]

LinuxmacOSWindows
Tool Enterprise

S0174: Responder

Responder is an open source tool used for LLMNR, NBT-NS and MDNS poisoning, with built-in HTTP/SMB/MSSQL/FTP/LDAP rogue authentication server supporting NTLMv1/NTLMv2/LMv2, Extended Security NTLMSSP and Basic HTTP authentication. [1]

Malware Enterprise

S9024: SPAWNCHIMERA

SPAWNCHIMERA is a backdoor that supports command and control and can inject malicious components into native processes.[1][2][3] SPAWNCHIMERA It incorporates capabilities from multiple tools within the SPAWN malware family, including SPAWNANT, SPAWNMOLE, and SPAWNSNAIL.[4][2][3] SPAWNCHIMERA was first reported in April 2024.[2] SPAWNCHIMERA has been observed in activity attributed to People's Republic of China (PRC) state-sponsored threat actors, including UNC5221..[4][5][2][6]

LinuxNetwork Devices
Malware Enterprise

S0367: Emotet

Emotet is a modular malware variant which is primarily used as a downloader for other malware variants such as TrickBot and IcedID. Emotet first emerged in June 2014, initially targeting the financial sector, and has expanded to multiple verticals over time.[1]

Windows
Malware Enterprise

S1204: cd00r

cd00r is an open-source backdoor for UNIX and UNIX-variant operating systems that was orginally released in 2000. cd00r source code is primarily based on a packet-capturing program as it utilizes a sniffer to listen for specific sequences of network traffic or "secret knock" before executing the attacker's code.[1][2]

Network Devices
Campaign Enterprise

C0056: RedPenguin

The RedPenguin project was launched by Juniper in July 2024 to investigate reported malware infections of Juniper MX Series routers. RedPenguin activity was separately attributed to UNC3886 and included the deployment of multiple custom versions of the publicly-available TINYSHELL backdoor on Juniper routers.[1][2]

Campaign Enterprise

C0046: ArcaneDoor

ArcaneDoor is a campaign targeting networking devices from Cisco and other vendors between July 2023 and April 2024, primarily focused on government and critical infrastructure networks. ArcaneDoor is associated with the deployment of the custom backdoors Line Runner and Line Dancer. ArcaneDoor is attributed to a group referred to as UAT4356 or STORM-1849, and is assessed to be a state-sponsored campaign.[1][2]

Relationship explorer

All related ATT&CK context

Mitigations

Mitigation direction

Change history

Object version and sync metadata

The fields below describe the current mirrored snapshot. When Glexia retains multiple ATT&CK source imports, you can open the table to compare the same object across releases (hashes and MITRE timestamps). For MITRE’s own release notes and roadmap, see ATT&CK resources — Updates .

ATT&CK release
19.1
Object version
1.7
Created
Modified
Raw hash
325a52d041f054f9...
Imported snapshots across ATT&CK releases (1)
Release Bundle imported Object version Modified Status Raw hash
19.1 1.7 Current bundle 325a52d041f0…
Raw source

Mirrored ATT&CK source object

The raw object is retained through the mirrored ATT&CK source bundle and object hash. The raw endpoint returns the exact object from the mirrored bundle when available.

Source references

External references and citations

MITRE external references are preserved separately from Glexia analysis so citations remain traceable to their original source records.

  1. [1]
    AWS Traffic Mirroring

    Amazon Web Services. (n.d.). How Traffic Mirroring works. Retrieved March 17, 2022.

    Open source URL
  2. [2]
    GCP Packet Mirroring

    Google Cloud. (n.d.). Packet Mirroring overview. Retrieved March 17, 2022.

    Open source URL
  3. [3]
    Azure Virtual Network TAP

    Microsoft. (2022, February 9). Virtual network TAP. Retrieved March 17, 2022.

    Open source URL
  4. [4]
    Rhino Security Labs AWS VPC Traffic Mirroring

    Spencer Gietzen. (2019, September 17). Abusing VPC Traffic Mirroring in AWS. Retrieved March 17, 2022.

    Open source URL
  5. [5]
    SpecterOps AWS Traffic Mirroring

    Luke Paine. (2020, March 11). Through the Looking Glass — Part 1. Retrieved March 17, 2022.

    Open source URL
  6. [6]
    US-CERT-TA18-106A

    US-CERT. (2018, April 20). Alert (TA18-106A) Russian State-Sponsored Cyber Actors Targeting Network Infrastructure Devices. Retrieved October 19, 2020.

    Open source URL
  7. [7]
    capture_embedded_packet_on_software

    Cisco. (2022, August 17). Configure and Capture Embedded Packet on Software. Retrieved July 13, 2022.

    Open source URL
  8. [8]
    mitre-attack T1040
    Open source URL
Source and licensing

Source: MITRE ATT&CK®. © 2026 The MITRE Corporation. This work is reproduced and distributed with the permission of The MITRE Corporation. MITRE ATT&CK and ATT&CK are registered trademarks of The MITRE Corporation. Glexia is not affiliated with or endorsed by MITRE.