type: attack-pattern
spec_version: 2.1
id: attack-pattern--2e34237d-8574-43f6-aace-ae2915de8597
created: 2020-03-02T19:05:18.137Z
created_by_ref: identity--c78cb6e5-0c4b-4611-8297-d1b8b55e40b5
revoked: no
external_references: source_name: mitre-attack
url: https://attack.mitre.org/techniques/T1566/001
external_id: T1566.001
source_name: ACSC Email Spoofing
description: Australian Cyber Security Centre. (2012, December). Mitigating Spoofed Emails Using Sender Policy Framework. Retrieved November 17, 2024.
url: https://web.archive.org/web/20210708014107/https://www.cyber.gov.au/sites/default/files/2019-03/spoof_email_sender_policy_framework.pdf
source_name: Unit 42 DarkHydrus July 2018
description: Falcone, R., et al. (2018, July 27). New Threat Actor Group DarkHydrus Targets Middle East Government. Retrieved August 2, 2018.
url: https://researchcenter.paloaltonetworks.com/2018/07/unit42-new-threat-actor-group-darkhydrus-targets-middle-east-government/
source_name: Microsoft Anti Spoofing
description: Microsoft. (2020, October 13). Anti-spoofing protection in EOP. Retrieved October 19, 2020.
url: https://docs.microsoft.com/en-us/microsoft-365/security/office-365-security/anti-spoofing-protection?view=o365-worldwide
source_name: Elastic - Koadiac Detection with EQL
description: Stepanic, D.. (2020, January 13). Embracing offensive tooling: Building detections against Koadic using EQL. Retrieved November 17, 2024.
url: https://www.elastic.co/security-labs/embracing-offensive-tooling-building-detections-against-koadic-using-eql
object_marking_refs: marking-definition--fa42a846-8d90-4e51-bc29-71d5b4802168
modified: 2025-10-24T17:48:35.522Z
name: Spearphishing Attachment
description: Adversaries may send spearphishing emails with a malicious attachment in an attempt to gain access to victim systems. Spearphishing attachment is a specific variant of spearphishing. Spearphishing attachment is different from other forms of spearphishing in that it employs the use of malware attached to an email. All forms of spearphishing are electronically delivered social engineering targeted at a specific individual, company, or industry. In this scenario, adversaries attach a file to the spearphishing email and usually rely upon [User Execution](https://attack.mitre.org/techniques/T1204) to gain execution.(Citation: Unit 42 DarkHydrus July 2018) Spearphishing may also involve social engineering techniques, such as posing as a trusted source.

There are many options for the attachment such as Microsoft Office documents, executables, PDFs, or archived files. Upon opening the attachment (and potentially clicking past protections), the adversary's payload exploits a vulnerability or directly executes on the user's system. The text of the spearphishing email usually tries to give a plausible reason why the file should be opened, and may explain how to bypass system protections in order to do so. The email may also contain instructions on how to decrypt an attachment, such as a zip file password, in order to evade email boundary defenses. Adversaries frequently manipulate file extensions and icons in order to make attached executables appear to be document files, or files exploiting one application appear to be a file for a different one. 
kill_chain_phases: kill_chain_name: mitre-attack
phase_name: initial-access
x_mitre_attack_spec_version: 3.2.0
x_mitre_contributors: Philip Winther
x_mitre_deprecated: no
x_mitre_domains: enterprise-attack
x_mitre_is_subtechnique: yes
x_mitre_modified_by_ref: identity--c78cb6e5-0c4b-4611-8297-d1b8b55e40b5
x_mitre_platforms: Linux
macOS
Windows
x_mitre_version: 2.2