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MITRE ATT&CK® Technique

T1021.004: SSH

Adversaries may use Valid Accounts to log into remote machines using Secure Shell (SSH). The adversary may then perform actions as the logged-on user.

SSH is a protocol that allows authorized users to open remote shells on other computers. Many Linux and macOS versions come with SSH installed by default, although typically disabled until the user enables it. On ESXi, SSH can be enabled either directly on the host (e.g., via `vim-cmd hostsvc/enable_ssh`) or via vCenter.[1][2][3] The SSH server can be configured to use standard password authentication or public-private keypairs in lieu of or in addition to a password. In this authentication scenario, the user’s public key must be in a special file on the computer running the server that lists which keypairs are allowed to login as that user (i.e., SSH Authorized Keys).

EnterpriseT1021.004Sub-techniqueObject v1.3 Modified
Glexia's Take

Analyst context for executives and security teams

Analyst confidence High

SSH-based lateral movement matters because it can turn a valid Linux, macOS, or ESXi account into remote control of another system. For leaders, the key issue is not that SSH exists, but whether the organization can prove who is allowed to use it, where it is enabled, and whether remote logins followed by suspicious activity would be noticed quickly.

Executive priority

Prioritize SSH governance on systems that support business-critical workloads, especially Linux, macOS, and ESXi. This technique is tied to lateral movement and depends on valid accounts, so it is a control and evidence issue for identity management, privileged access, incident response readiness, and auditability. Executives should ask whether SSH is disabled where unnecessary, whether account lifecycle controls remove stale access, whether MFA is applied where feasible, and whether SOC teams can investigate SSH logins with enough context to distinguish administration from misuse.

Technical view

ATT&CK provides no official detection text for this sub-technique, but the relationship to DET0596 points defenders toward behavioral detection of remote SSH logins followed by post-login execution. SOC and detection teams should validate coverage across ESXi, Linux, and macOS for SSH authentication events, source and destination context, user identity, session timing, and commands or processes started after login. On ESXi, validation should include whether SSH enablement on hosts or through vCenter is logged and reviewed. Detection should be correlated with Valid Accounts behavior and SSH Authorized Keys changes where telemetry exists.

Likely telemetry

  • SSH authentication logs showing successful and failed remote logins
  • User, source host/IP, destination host, and session timing for SSH connections
  • Process execution or shell activity after SSH login
  • ESXi host and vCenter events related to SSH being enabled or used
  • Account lifecycle, privilege, and group membership records

Detection direction

  • Validate whether detections look for remote SSH login followed by unusual or high-risk post-login execution, consistent with DET0596.
  • Baseline legitimate administrative SSH patterns to reduce false positives from routine operations, automation, and maintenance windows.
  • Tune for unusual source-to-destination paths, first-time user-to-host access, access outside expected hours, and SSH use on systems where it is normally disabled.
  • For ESXi, monitor both SSH enablement and subsequent login activity; missing vCenter or host-level logging is a material blind spot.
  • Correlate SSH activity with account changes and SSH authorized key modifications because the technique depends on valid accounts and may intersect with authorized key persistence.

Mitigation priorities

  • Start by disabling or removing SSH where it is not operationally required, aligning with M1042.
  • Apply user account management controls from M1018: least privilege, timely deactivation, review of privileged accounts, and removal of stale access.
  • Use MFA where supported and appropriate for SSH access, consistent with M1032, especially for privileged or critical systems.
  • Restrict who can enable SSH on ESXi and review administrative paths such as host-level configuration and vCenter-mediated enablement.
  • Maintain an inventory of systems where SSH is enabled and require a documented business owner for exceptions.
Analyst notes and limits

This object is a sub-technique of Remote Services and is mapped to lateral movement. ATT&CK relationships show use by multiple campaigns and groups, which supports the technique’s broad relevance, but local risk should be judged by the organization’s SSH exposure, administrative model, and telemetry quality. The strongest defensive value comes from combining identity controls with behavioral monitoring after login.

MITRE does not provide an official detection section for this object. The take is therefore based on the official description, platforms, tactics, external references, and listed relationships, including DET0596 and mitigations M1018, M1032, and M1042. It does not assert active exploitation or guaranteed detection coverage in any environment.

Official MITRE ATT&CK definition

SSH

Adversaries may use Valid Accounts to log into remote machines using Secure Shell (SSH). The adversary may then perform actions as the logged-on user.

SSH is a protocol that allows authorized users to open remote shells on other computers. Many Linux and macOS versions come with SSH installed by default, although typically disabled until the user enables it. On ESXi, SSH can be enabled either directly on the host (e.g., via `vim-cmd hostsvc/enable_ssh`) or via vCenter.[1][2][3] The SSH server can be configured to use standard password authentication or public-private keypairs in lieu of or in addition to a password. In this authentication scenario, the user’s public key must be in a special file on the computer running the server that lists which keypairs are allowed to login as that user (i.e., SSH Authorized Keys).

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.

ATT&CK relationship table

Related techniques

This mirrors the MITRE pattern of making group, software, campaign, and technique relationships scannable. Relationship notes come from mirrored ATT&CK relationship text when available.

1 rows
Domain ID Name Relationship / procedure
Enterprise T1021 Remote Services This object subtechnique of Remote Services.
Associated objects

Groups, software, and campaigns

Group Enterprise

G0046: FIN7

FIN7 is a financially-motivated threat group that has been active since 2013. FIN7 has targeted the retail, restaurant, hospitality, software, consulting, financial services, medical equipment, cloud services, media, food and beverage, transportation, pharmaceutical, and utilities industries in the United States. A portion of FIN7 was operated out of a front company called Combi Security and often used point-of-sale malware for targeting efforts. Since 2020, FIN7 shifted operations to big game hunting (BGH), including use of REvil ransomware and their own Ransomware-as-a-Service (RaaS), Darkside. FIN7 may be linked to the Carbanak Group, but multiple threat groups have been observed using Carbanak, leading these groups to be tracked separately.[1][2][3][4][5][6][7]

Group Enterprise

G0032: Lazarus Group

Lazarus Group is a North Korean state-sponsored cyber threat group attributed to the Reconnaissance General Bureau (RGB). [1] [2] Lazarus Group has been active since at least 2009 and is reportedly responsible for the November 2014 destructive wiper attack on Sony Pictures Entertainment, identified by Novetta as part of Operation Blockbuster. Malware used by Lazarus Group correlates to other reported campaigns, including Operation Flame, Operation 1Mission, Operation Troy, DarkSeoul, and Ten Days of Rain.[3]

North Korea’s cyber operations have shown a consistent pattern of adaptation, forming and reorganizing units as national priorities shift. These units frequently share personnel, infrastructure, malware, and tradecraft, making it difficult to attribute specific operations with high confidence. Public reporting often uses “Lazarus Group” as an umbrella term for multiple North Korean cyber operators conducting espionage, destructive attacks, and financially motivated campaigns.[4][5][6]

Group Enterprise

G0065: Leviathan

Leviathan is a Chinese state-sponsored cyber espionage group that has been attributed to the Ministry of State Security's (MSS) Hainan State Security Department and an affiliated front company.[1] Active since at least 2009, Leviathan has targeted the following sectors: academia, aerospace/aviation, biomedical, defense industrial base, government, healthcare, manufacturing, maritime, and transportation across the US, Canada, Australia, Europe, the Middle East, and Southeast Asia.[1][2][3][4]

Group Enterprise

G1015: Scattered Spider

Scattered Spider is a native English-speaking cybercriminal group active since at least 2022. [1] [2] The group initially targeted customer relationship management (CRM) providers, business process outsourcing (BPO) firms, and telecommunications and technology companies before expanding in 2023 to gaming, hospitality, retail, managed service provider (MSP), manufacturing, and financial sectors. [2] Scattered Spider relies heavily on social engineering, including impersonating IT and help-desk staff, to gain initial access, bypass multi-factor authentication (MFA), and compromise enterprise networks. The group has adapted its tooling to evade endpoint detection and response (EDR) defenses and used ransomware for financial gain. [3] [4] [5] Scattered Spider had expanded into hybrid cloud and identity environments, using help-desk impersonation and MFA bypass to obtain administrator access in Okta, AWS, and Office 365. [6]

Group Enterprise

G0098: BlackTech

BlackTech is a suspected Chinese cyber espionage group that has primarily targeted organizations in East Asia--particularly Taiwan, Japan, and Hong Kong--and the US since at least 2013. BlackTech has used a combination of custom malware, dual-use tools, and living off the land tactics to compromise media, construction, engineering, electronics, and financial company networks.[1][2][3]

Group Enterprise

G0143: Aquatic Panda

Aquatic Panda is a suspected China-based threat group with a dual mission of intelligence collection and industrial espionage. Active since at least May 2020, Aquatic Panda has primarily targeted entities in the telecommunications, technology, and government sectors.[1]

Group Enterprise

G0036: GCMAN

GCMAN is a threat group that focuses on targeting banks for the purpose of transferring money to e-currency services. [1]

Group Enterprise

G0117: Fox Kitten

Fox Kitten is threat actor with a suspected nexus to the Iranian government that has been active since at least 2017 against entities in the Middle East, North Africa, Europe, Australia, and North America. Fox Kitten has targeted multiple industrial verticals including oil and gas, technology, government, defense, healthcare, manufacturing, and engineering.[1][2][3][4]

Group Enterprise

G0139: TeamTNT

TeamTNT is a threat group that has primarily targeted cloud and containerized environments. The group as been active since at least October 2019 and has mainly focused its efforts on leveraging cloud and container resources to deploy cryptocurrency miners in victim environments.[1][2][3][4][5][6][7][8][9]

Group Enterprise

G1046: Storm-1811

Storm-1811 is a financially-motivated entity linked to Black Basta ransomware deployment. Storm-1811 is notable for unique phishing and social engineering mechanisms for initial access, such as overloading victim email inboxes with non-malicious spam to prompt a fake "help desk" interaction leading to the deployment of adversary tools and capabilities.[1][2][3][4]

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

G0049: OilRig

OilRig is a suspected Iranian threat group that has targeted Middle Eastern and international victims since at least 2014. The group has targeted a variety of sectors, including financial, government, energy, chemical, and telecommunications. It appears the group carries out supply chain attacks, leveraging the trust relationship between organizations to attack their primary targets. The group works on behalf of the Iranian government based on infrastructure details that contain references to Iran, use of Iranian infrastructure, and targeting that aligns with nation-state interests.[1][2][3][4][5][6][7]

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
Malware Enterprise

S0154: Cobalt Strike

Cobalt Strike is a commercial, full-featured, remote access tool that bills itself as “adversary simulation software designed to execute targeted attacks and emulate the post-exploitation actions of advanced threat actors”. Cobalt Strike’s interactive post-exploit capabilities cover the full range of ATT&CK tactics, all executed within a single, integrated system.[1]

In addition to its own capabilities, Cobalt Strike leverages the capabilities of other well-known tools such as Metasploit and Mimikatz.[1]

LinuxmacOSWindows
Malware Enterprise

S1187: reGeorg

reGeorg is an open-source web shell written in Python that can be used as a proxy to bypass firewall rules and tunnel data in and out of targeted networks.[1][2]

Network DevicesWindowsmacOS
Malware Enterprise

S0599: Kinsing

Kinsing is Golang-based malware that runs a cryptocurrency miner and attempts to spread itself to other hosts in the victim environment. [1][2][3]

ContainersLinux
Malware Enterprise

S1242: Qilin

Qilin is a ransomware family operated as a ransomware-as-a-service (RaaS) that has been active since at least 2022. It includes variants written in Go and Rust capable of targeting Windows, Linux, and VMware ESXi environments. Qilin shares functionality overlaps with Black Basta, REvil, and BlackCat ransomware. Qilin affiliates have targeted multiple entities worldwide with the majority of victims in the US, France, Canada, and the UK, primarily in the manufacturing, technology, financial services, and healthcare sectors.[1][2][3][4][5]

ESXiWindowsLinux
Campaign Enterprise

C0029: Cutting Edge

Cutting Edge was a campaign conducted by suspected China-nexus espionage actors, variously identified as UNC5221/UTA0178 and UNC5325, that began as early as December 2023 with the exploitation of zero-day vulnerabilities in Ivanti Connect Secure (previously Pulse Secure) VPN appliances. Cutting Edge targeted the U.S. defense industrial base and multiple sectors globally including telecommunications, financial, aerospace, and technology. Cutting Edge featured the use of defense evasion and living-off-the-land (LoTL) techniques along with the deployment of web shells and other custom malware.[1][2][3][4][5]

Campaign Enterprise

C0049: Leviathan Australian Intrusions

Leviathan Australian Intrusions consisted of at least two long-term intrusions against victims in Australia by Leviathan, relying on similar tradecraft such as external service exploitation followed by extensive credential capture and re-use to enable privilege escalation and lateral movement. Leviathan Australian Intrusions were focused on exfiltrating sensitive data including valid credentials for the victim organizations.[1]

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
1.3
Created
Modified
Raw hash
d17d5950b374beaa...
Imported snapshots across ATT&CK releases (1)
Release Bundle imported Object version Modified Status Raw hash
19.1 1.3 Current bundle d17d5950b374…
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]
    Sygnia ESXi Ransomware 2025

    Zhongyuan Hau (Aaron), Ren Jie Yow, and Yoav Mazor. (2025, January 21). ESXi Ransomware Attacks: Stealthy Persistence through. Retrieved March 27, 2025.

    Open source URL
  2. [2]
    TrendMicro ESXI Ransomware

    Junestherry Dela Cruz. (2022, January 24). Analysis and Impact of LockBit Ransomware’s First Linux and VMware ESXi Variant. Retrieved March 26, 2025.

    Open source URL
  3. [3]
    Sygnia Abyss Locker 2025

    Abigail See, Zhongyuan (Aaron) Hau, Ren Jie Yow, Yoav Mazor, Omer Kidron, and Oren Biderman. (2025, February 4). The Anatomy of Abyss Locker Ransomware Attack. Retrieved April 4, 2025.

    Open source URL
  4. [4]
    Apple Unified Log Analysis Remote Login and Screen Sharing

    Sarah Edwards. (2020, April 30). Analysis of Apple Unified Logs: Quarantine Edition [Entry 6] – Working From Home? Remote Logins. Retrieved August 19, 2021.

    Open source URL
  5. [5]
    mitre-attack T1021.004
    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.