T1566: Phishing
Adversaries may send phishing messages to gain access to victim systems. All forms of phishing are electronically delivered social engineering. Phishing can be targeted, known as spearphishing. In spearphishing, a specific individual, company, or industry will be targeted by the adversary. More generally, adversaries can conduct non-targeted phishing, such as in mass malware spam campaigns.
Adversaries may send victims emails containing malicious attachments or links, typically to execute malicious code on victim systems. Phishing may also be conducted via third-party services, like social media platforms. Phishing may also involve social engineering techniques, such as posing as a trusted source, as well as evasive techniques such as removing or manipulating emails or metadata/headers from compromised accounts being abused to send messages (e.g., Email Hiding Rules).[1][2] Another way to accomplish this is by Email Spoofing[3] the identity of the sender, which can be used to fool both the human recipient as well as automated security tools,[4] or by including the intended target as a party to an existing email thread that includes malicious files or links (i.e., "thread hijacking").[5]
Victims may also receive phishing messages that instruct them to call a phone number where they are directed to visit a malicious URL, download malware,[6][7] or install adversary-accessible remote management tools onto their computer (i.e., User Execution).[8]
Analyst context for executives and security teams
Phishing matters because it is often the first decision point in an incident: a user, inbox, collaboration service, link, attachment, or phone-driven request becomes the path into enterprise systems. For leaders, the issue is not whether users can be fooled; it is whether the organization can reduce exposure, collect enough evidence, and respond quickly across email, identity provider, Office, SaaS, endpoint, and web controls.
Executive priority
Treat T1566 as a resilience and readiness control area, not just a security awareness topic. Executive questions should include: Are phishing reports triaged fast enough? Do identity, email, SaaS, endpoint, web, and audit logs support incident reconstruction? Are controls tested against attachments, links, third-party service messages, spoofing, thread hijacking, and voice/callback scenarios? The related mitigations point to a balanced program: user training, web-content restriction, network prevention, auditing, antimalware, and secure software configuration.
Technical view
ATT&CK lists Phishing as an Initial Access technique across Identity Provider, Linux, macOS, Office Suite, SaaS, and Windows, with sub-techniques for spearphishing attachment, spearphishing link, spearphishing via service, and spearphishing voice. SOC and IR teams should validate coverage across the full chain: message delivery, user interaction, URL or attachment handling, identity events, endpoint execution, and any remote management tool installation prompted by social engineering. Because MITRE does not provide official detection text for this object, teams should map local analytics to DET0070 and test whether logs can connect the initial message to subsequent authentication, web, Office, SaaS, or endpoint activity.
Likely telemetry
- Email security gateway and mailbox audit logs, including sender, recipient, headers, attachments, links, forwarding, deletion, and rule changes where available
- Identity provider authentication, MFA, session, consent, and OAuth/application authorization events
- Office suite and document telemetry, including attachment open, macro/script activity, and protected-view or content-enablement signals where collected
- Endpoint security telemetry on Windows, macOS, and Linux for downloaded files, process execution, script interpreters, browser activity, and remote management tool installation
- Web proxy, DNS, secure web gateway, and network intrusion prevention logs for URL access, redirects, downloads, and blocked destinations
Detection direction
- Validate detections separately for the ATT&CK sub-technique paths: malicious attachments, malicious links, third-party services, and voice/callback-driven access.
- Tune for spoofing, thread hijacking, compromised-account sending, and message manipulation because these can weaken assumptions based only on sender reputation or obvious malicious content.
- Correlate message events with identity and endpoint activity: suspicious sign-ins, OAuth consent, link clicks, document execution, downloads, and installation of remote management tools are more decision-useful together than in isolation.
- Account for false positives from legitimate marketing, file sharing, business SaaS invitations, and remote support workflows; detection quality depends on baselining approved services and expected user behavior.
- Confirm retention and accessibility of mailbox, IdP, SaaS, web, and endpoint logs before an incident; phishing investigations often fail when the first message or post-click activity cannot be reconstructed.
Mitigation priorities
- Start with M1047 Audit: ensure the organization records enough email, identity, SaaS, web, and endpoint activity to support investigation and compliance evidence.
- Apply M1017 User Training focused on recognition and reporting of emails, service messages, spoofing, thread hijacking, and voice/callback social engineering.
- Use M1021 Restrict Web-Based Content to reduce access to malicious sites, unsafe downloads, and risky browser behaviors associated with links and downloads.
- Use M1054 Software Configuration to harden email, Office, browser, SaaS, and identity settings where applicable to reduce risky default behavior.
- Maintain M1049 Antivirus/Antimalware on relevant endpoints to help block or remediate malicious files delivered through attachments or downloads.
Analyst notes and limits
The relationship set shows broad relevance: multiple named groups and malware/ransomware software entries are associated with use of Phishing, and the sub-techniques cover attachments, links, third-party services, and voice. This should inform coverage validation, not be read as evidence that any specific organization is targeted or that any named actor is present. For Glexia-style assessments, the most valuable output is usually a control-and-telemetry gap view across initial access paths rather than a single email-security score.
The official ATT&CK object does not provide detection guidance, so detection recommendations must be validated against local architecture and DET0070 rather than treated as MITRE-prescribed analytics. The supplied data supports the listed platforms and mitigations but does not prove active exploitation, customer exposure, successful compromise, or guaranteed detection coverage.
Phishing
Adversaries may send phishing messages to gain access to victim systems. All forms of phishing are electronically delivered social engineering. Phishing can be targeted, known as spearphishing. In spearphishing, a specific individual, company, or industry will be targeted by the adversary. More generally, adversaries can conduct non-targeted phishing, such as in mass malware spam campaigns.
Adversaries may send victims emails containing malicious attachments or links, typically to execute malicious code on victim systems. Phishing may also be conducted via third-party services, like social media platforms. Phishing may also involve social engineering techniques, such as posing as a trusted source, as well as evasive techniques such as removing or manipulating emails or metadata/headers from compromised accounts being abused to send messages (e.g., Email Hiding Rules).[1][2] Another way to accomplish this is by Email Spoofing[3] the identity of the sender, which can be used to fool both the human recipient as well as automated security tools,[4] or by including the intended target as a party to an existing email thread that includes malicious files or links (i.e., "thread hijacking").[5]
Victims may also receive phishing messages that instruct them to call a phone number where they are directed to visit a malicious URL, download malware,[6][7] or install adversary-accessible remote management tools onto their computer (i.e., User Execution).[8]
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.
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.
| Domain | ID | Name | Relationship / procedure |
|---|---|---|---|
| Enterprise | T1566.002 | Spearphishing Link Sub-technique | Spearphishing Link subtechnique of this object. |
| Enterprise | T1566.001 | Spearphishing Attachment Sub-technique | Spearphishing Attachment subtechnique of this object. |
| Enterprise | T1566.004 | Spearphishing Voice Sub-technique | Spearphishing Voice subtechnique of this object. |
| Enterprise | T1566.003 | Spearphishing via Service Sub-technique | Spearphishing via Service subtechnique of this object. |
Groups, software, and campaigns
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.
G1055: VOID MANTICORE
VOID MANTICORE is a threat group assessed to operate on behalf of Iran’s Ministry of Intelligence and Security (MOIS).[1] Active since at least mid-2022, VOID MANTICORE has targeted government entities, critical infrastructure, and private sector organizations across Albania, Israel, and the United States.[1][2] VOID MANTICORE conducts destructive cyber operations, combining wiper attacks with hack-and-leak campaigns. The group has operated under multiple public-facing personas, including HomeLand Justice in operations against Albania, Karma and Karma Below in campaigns targeting Israeli organizations, and Handala Hack, its current primary persona, which has claimed activity against Israeli and U.S. entities, including a March 2026 attack against Stryker Corporation.[1][3] VOID MANTICORE has been observed collaborating with Scarred Manticore, which has been linked to initial access operations preceding VOID MANTICORE’s activity.[4]
G1032: INC Ransom
INC Ransom is a ransomware and data extortion threat group associated with the deployment of INC Ransomware that has been active since at least July 2023. INC Ransom has targeted organizations worldwide most commonly in the industrial, healthcare, and education sectors in the US and Europe.[1][2][3][4]
G0069: MuddyWater
MuddyWater is a cyber espionage group assessed to be a subordinate element within Iran's Ministry of Intelligence and Security (MOIS).[1] Since at least 2017, MuddyWater has targeted a range of government and private organizations across sectors, including telecommunications, local government, finance, defense, and oil and natural gas organizations, in the Middle East (specifically the UAE and Saudi Arabia), Asia, Africa, Europe, and North America. MuddyWater has reused domains dating back to October 2025, and has a preference for NameCheap and Hosterdaddy Private Limited (AS136557). In late 2025 and early 2026, MuddyWater used commercial satellite internet (i.e., Starlink) for command and control (C2) communication. [2][3][4][5][6][7][8][9][10][11][12][13]
G1041: Sea Turtle
Sea Turtle is a Türkiye-linked threat actor active since at least 2017 performing espionage and service provider compromise operations against victims in Asia, Europe, and North America. Sea Turtle is notable for targeting registrars managing ccTLDs and complex DNS-based intrusions where the threat actor compromised DNS providers to hijack DNS resolution for ultimate victims, enabling Sea Turtle to spoof log in portals and other applications for credential collection.[1][2][3][4]
G0001: Axiom
Axiom is a suspected Chinese cyber espionage group that has targeted the aerospace, defense, government, manufacturing, and media sectors since at least 2008. Some reporting suggests a degree of overlap between Axiom and Winnti Group but the two groups appear to be distinct based on differences in reporting on TTPs and targeting.[1][2][3]
G1049: AppleJeus
AppleJeus is a North Korean state-sponsored threat group attributed to the Reconnaissance General Bureau. Associated with the broader Lazarus Group umbrella of actors, AppleJeus has been active since at least 2018 and is closely aligned in resources with TEMP.hermit, another DPRK-affiliated group under the same umbrella.[1] The group’s primary mission is to generate and launder revenue to provide financial support to the government. AppleJeus primarily targets the cryptocurrency industry and is most notably responsible for the 3CX Supply Chain Attack.[2] The group traditionally deploys malicious cryptocurrency software in combination with Phishing. From these compromised environments, it selectively deploys additional backdoors to enable extended operations against high-value financial targets.[3][4]
G0115: GOLD SOUTHFIELD
GOLD SOUTHFIELD is a financially motivated threat group active since at least 2018 that operates the REvil Ransomware-as-a Service (RaaS). GOLD SOUTHFIELD provides backend infrastructure for affiliates recruited on underground forums to perpetrate high value deployments. By early 2020, GOLD SOUTHFIELD started capitalizing on the new trend of stealing data and further extorting the victim to pay for their data to not get publicly leaked.[1][2][3][4]
S0009: Hikit
S1139: INC Ransomware
INC Ransomware is a ransomware strain that has been used by the INC Ransom group since at least 2023 against multiple industry sectors worldwide. INC Ransomware can employ partial encryption combined with multi-threading to speed encryption.[1][2][3]
S1073: Royal
Royal is ransomware that first appeared in early 2022; a version that also targets ESXi servers was later observed in February 2023. Royal employs partial encryption and multiple threads to evade detection and speed encryption. Royal has been used in attacks against multiple industries worldwide--including critical infrastructure. Security researchers have identified similarities in the encryption routines and TTPs used in Royal and Conti attacks and noted a possible connection between their operators.[1][2][3][4][5]
All related ATT&CK context
Mitigation direction
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 .
Imported snapshots across ATT&CK releases (1)
| Release | Bundle imported | Object version | Modified | Status | Raw hash |
|---|---|---|---|---|---|
| 19.1 | 2.7 | Current bundle | 42b57f03efcc… |
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.
External references and citations
MITRE external references are preserved separately from Glexia analysis so citations remain traceable to their original source records.
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[1]
Microsoft OAuth Spam 2022
Microsoft. (2023, September 22). Malicious OAuth applications abuse cloud email services to spread spam. Retrieved March 13, 2023.
Open source URL -
[2]
Palo Alto Unit 42 VBA Infostealer 2014
Vicky Ray and Rob Downs. (2014, October 29). Examining a VBA-Initiated Infostealer Campaign. Retrieved March 13, 2023.
Open source URL -
[3]
Proofpoint-spoof
Proofpoint. (n.d.). What Is Email Spoofing?. Retrieved February 24, 2023.
Open source URL -
[4]
cyberproof-double-bounce
Itkin, Liora. (2022, September 1). Double-bounced attacks with email spoofing . Retrieved February 24, 2023.
Open source URL -
[5]
phishing-krebs
Brian Krebs. (2024, March 28). Thread Hijacking: Phishes That Prey on Your Curiosity. Retrieved September 27, 2024.
Open source URL -
[6]
sygnia Luna Month
Oren Biderman, Tomer Lahiyani, Noam Lifshitz, Ori Porag. (n.d.). LUNA MOTH: THE THREAT ACTORS BEHIND RECENT FALSE SUBSCRIPTION SCAMS. Retrieved February 2, 2023.
Open source URL -
[7]
CISA Remote Monitoring and Management Software
CISA. (n.d.). Protecting Against Malicious Use of Remote Monitoring and Management Software. Retrieved February 2, 2023.
Open source URL -
[8]
Unit42 Luna Moth
Kristopher Russo. (n.d.). Luna Moth Callback Phishing Campaign. Retrieved February 2, 2023.
Open source URL -
[9]
mitre-attack T1566Open source URL
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