t1566-phishing

name	T1566_phishing
description	Adversaries may send phishing messages to gain access to victim systems.
category	input-validation
version	18.1
author	cyberstrike-official
tags	["mitre-attack","enterprise","t1566","initial-access","identity-provider","linux","macos","office-suite","saas","windows"]
technique_id	T1566
tactic	initial-access
all_tactics	["initial-access"]
platforms	["Identity Provider","Linux","macOS","Office Suite","SaaS","Windows"]
mitre_url	https://attack.mitre.org/techniques/T1566
tech_stack	["identity","linux","macos","office","saas","windows"]
cwe_ids	["CWE-20"]
chains_with	["T1566.001","T1566.002","T1566.003","T1566.004"]
prerequisites	[]
severity_boost	{"T1566.001":"Chain with T1566.001 for deeper attack path","T1566.002":"Chain with T1566.002 for deeper attack path","T1566.003":"Chain with T1566.003 for deeper attack path"}

T1566 Phishing

High-Level Description

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

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, or install adversary-accessible remote management tools onto their computer (i.e., User Execution).

Kill Chain Phase

• Initial Access (TA0001)

Platforms: Identity Provider, Linux, macOS, Office Suite, SaaS, Windows

What to Check

• Identify if Phishing technique is applicable to target environment
• Check Identity Provider systems for indicators of Phishing
• Check Linux systems for indicators of Phishing
• Check macOS systems for indicators of Phishing
• Verify mitigations are bypassed or absent (6 known mitigations)
• Assess detection coverage (1 detection strategies)

How to Test

Manual Testing

1. Identify Attack Surface: Determine if the target environment is susceptible to Phishing by examining the target platforms (Identity Provider, Linux, macOS).

2. Assess Existing Defenses: Review whether mitigations for T1566 are in place. If defenses are absent or misconfigured, this technique may be exploitable.