MITRE ATT&CK Technique
Persistence T1137.003
Description

Adversaries may abuse Microsoft Outlook forms to obtain persistence on a compromised system. Outlook forms are used as templates for presentation and functionality in Outlook messages. Custom Outlook forms can be created that will execute code when a specifically crafted email is sent by an adversary utilizing the same custom Outlook form.(Citation: SensePost Outlook Forms) Once malicious forms have been added to the user’s mailbox, they will be loaded when Outlook is started. Malicious forms will execute when an adversary sends a specifically crafted email to the user.(Citation: SensePost Outlook Forms)

Supported Platforms
Windows Office Suite
Created

April 29, 2026

Last Updated

April 29, 2026

STIX Data
{'created': '2019-11-07T20:06:02.624Z',
 'created_by_ref': 'identity--c78cb6e5-0c4b-4611-8297-d1b8b55e40b5',
 'description': 'Adversaries may abuse Microsoft Outlook forms to obtain '
                'persistence on a compromised system. Outlook forms are used '
                'as templates for presentation and functionality in Outlook '
                'messages. Custom Outlook forms can be created that will '
                'execute code when a specifically crafted email is sent by an '
                'adversary utilizing the same custom Outlook form.(Citation: '
                'SensePost Outlook Forms)\n'
                '\n'
                'Once malicious forms have been added to the user’s mailbox, '
                'they will be loaded when Outlook is started. Malicious forms '
                'will execute when an adversary sends a specifically crafted '
                'email to the user.(Citation: SensePost Outlook Forms)',
 'external_references': [{'external_id': 'T1137.003',
                          'source_name': 'mitre-attack',
                          'url': 'https://attack.mitre.org/techniques/T1137/003'},
                         {'description': 'Fox, C., Vangel, D. (2018, April '
                                         '22). Detect and Remediate Outlook '
                                         'Rules and Custom Forms Injections '
                                         'Attacks in Office 365. Retrieved '
                                         'February 4, 2019.',
                          'source_name': 'Microsoft Detect Outlook Forms',
                          'url': 'https://docs.microsoft.com/en-us/office365/securitycompliance/detect-and-remediate-outlook-rules-forms-attack'},
                         {'description': 'SensePost. (2017, September 21). '
                                         'NotRuler - The opposite of Ruler, '
                                         'provides blue teams with the ability '
                                         'to detect Ruler usage against '
                                         'Exchange. Retrieved February 4, '
                                         '2019.',
                          'source_name': 'SensePost NotRuler',
                          'url': 'https://github.com/sensepost/notruler'},
                         {'description': 'Stalmans, E. (2017, April 28). '
                                         'Outlook Forms and Shells. Retrieved '
                                         'February 4, 2019.',
                          'source_name': 'SensePost Outlook Forms',
                          'url': 'https://sensepost.com/blog/2017/outlook-forms-and-shells/'}],
 'id': 'attack-pattern--a9e2cea0-c805-4bf8-9e31-f5f0513a3634',
 'kill_chain_phases': [{'kill_chain_name': 'mitre-attack',
                        'phase_name': 'persistence'}],
 'modified': '2025-10-24T17:49:12.562Z',
 'name': 'Outlook Forms',
 'object_marking_refs': ['marking-definition--fa42a846-8d90-4e51-bc29-71d5b4802168'],
 'revoked': False,
 'spec_version': '2.1',
 'type': 'attack-pattern',
 'x_mitre_attack_spec_version': '3.2.0',
 'x_mitre_deprecated': False,
 'x_mitre_detection': '',
 'x_mitre_domains': ['enterprise-attack'],
 'x_mitre_is_subtechnique': True,
 'x_mitre_modified_by_ref': 'identity--c78cb6e5-0c4b-4611-8297-d1b8b55e40b5',
 'x_mitre_platforms': ['Windows', 'Office Suite'],
 'x_mitre_version': '1.2'}
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