tool

CALENDAR S0025

Type: malware
Platform: Windows
Created: 31 May 2017
Last modified: 25 April 2025

CALENDAR is malware used by APT1 that mimics legitimate Gmail Calendar traffic. [1]

TechniquesBottom 7%

TacticsBottom 12%

Threat groupunranked

CampaignsNone recorded

Enterprise ATT&CK only. Any Mobile or ICS rows on the same ATT&CK page are not carried.

MITRE reference S0025

Windows Command Shell T1059.003↗

CALENDAR has a command to run cmd.exe to execute commands.2

Execution61 detection rules

Bidirectional Communication T1102.002↗

The CALENDAR malware communicates through the use of events in Google Calendar.3 4

Command and Control6 detection rules

Standing S0025

Reach is how much of ATT&CK this tool touches. Coverage is how well defended each thing it does is, as a median per technique rather than a total — a total would just restate the reach. Each figure is ranked against all 825 ATT&CK software entries only where that population actually spreads. Where most of the population shares one value, a percentile would rank the tie instead of the entity, so the raw value is shown and no rank is claimed.

Reach

Techniques2Bottom 7%

7th percentile · 93% of 825 ATT&CK software entries have more Enterprise techniques.

Tactics2Bottom 12%

12th percentile · 88% of 825 ATT&CK software entries have more tactics spanned.

Threat group161% tie · 22 values

61% of the population shares a single value across only 22 distinct values, so a percentile here would rank the tie, not the entity.

Campaigns085% tie · 8 values

85% of the population shares a single value across only 8 distinct values, so a percentile here would rank the tie, not the entity.

Coverage

Rules / technique33.5medTop 19%

81st percentile · 81% of 825 ATT&CK software entries have this many detection rules per technique or fewer.

Tests / technique3.5med

Detection coverage S0025

67 distinct rules cover the 2 techniques recorded for this tool. 50 Sigma · 17 Splunk.

2 covered by at least one rule67 distinct rules in total

Drag headers to reorder | Drag edges to resize

Loading detections...

Select	Title	Description	Category	Status	Event	Product	MITRE ATT&CK	CVEs	Severity	Author	Created	Updated	ID	Refs

© 2026 The MITRE Corporation. ATT&CK® and D3FEND™ data reproduced with permission. SigmaHQ detection rules licensed under DRL 1.1. attack.mitre.org · d3fend.mitre.org · CAR analytics licensed under Apache 2.0 · car.mitre.org

MITRE reference S0025

Reach

Coverage

How it got here