CyberStack

MITRE ATT&CK / Techniques / T1566

Phishing

ID
T1566
Tactics
TA0001 Initial Access
Platforms
Identity Provider, Linux, macOS, Office Suite, SaaS, Windows
Data sources
Application Log Content, File Creation, Process Creation, Logon Session Creation
Source
attack.mitre.org
MITRE last modified
18 Sep 2026

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) or delivered via calendar invites. 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).[3][4] Another way to accomplish this is by Email Spoofing[5] the identity of the sender, which can be used to fool both the human recipient as well as automated security tools,[6] or by including the intended target as a party to an existing email thread that includes malicious files or links (i.e., "thread hijacking").[7]

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,[8][9] or install adversary-accessible remote management tools onto their computer (i.e., User Execution).[10]

Sub-techniques (4)

Detection

Mitigations (6)

M1017 User Training

Users can be trained to identify social engineering techniques and phishing emails.

M1021 Restrict Web-Based Content

Determine if certain websites or attachment types (ex: .scr, .exe, .pif, .cpl, etc.) that can be used for phishing are necessary for business operations and consider blocking access if activity cannot be monitored well or if it poses a significant risk.

M1031 Network Intrusion Prevention

Network intrusion prevention systems and systems designed to scan and remove malicious email attachments or links can be used to block activity.

M1047 Audit

Perform audits or scans of systems, permissions, insecure software, insecure configurations, etc. to identify potential weaknesses.

M1049 Antivirus/Antimalware

Anti-virus can automatically quarantine suspicious files.

M1054 Software Configuration

Use anti-spoofing and email authentication mechanisms to filter messages based on validity checks of the sender domain (using SPF) and integrity of messages (using DKIM). Enabling these mechanisms within an organization (through policies such as DMARC) may enable recipients (intra-org and cross domain) to perform similar message filtering and validation.[1][2]

Groups (8)

Software (3)

References

  1. Microsoft Anti Spoofing
  2. ACSC Email Spoofing
  3. Microsoft OAuth Spam 2022
  4. Palo Alto Unit 42 VBA Infostealer 2014
  5. Proofpoint-spoof
  6. cyberproof-double-bounce
  7. phishing-krebs
  8. sygnia Luna Month
  9. CISA Remote Monitoring and Management Software
  10. Unit42 Luna Moth