malware

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.

CALENDAR MITRE reference S0025

Windows Command Shell T1059.003 ↗

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

Execution63 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 malware 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 / technique34.5medTop 19%

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

Tests / technique3.5medBottom 19%

19th percentile · 81% of 825 ATT&CK software entries have more atomic tests per technique.

Data comps / technique3.5med54% tie · 11 values

54% of the population shares a single value across only 11 distinct values, so a percentile here would rank the tie, not the entity.

Mitigations / technique1.5med65th pct

65th percentile · 65% of 825 ATT&CK software entries have this many mitigations per technique or fewer.

5 of 8 axes carry an honest rank on this page. Coverage medians are taken across this malware’s 2 Enterprise techniques.

Range

Technique Campaign use over its cumulative rule count.

Campaigns · 0Sigma rules (cumulative) · 50Splunk ESCU (cumulative) · 19

Standing S0025

Select	Description	Category	Status	Event	OS	Product	MITRE ATT&CK	CVEs	Severity	Author	Created	Updated	ID	Refs
	Detects when AppLocker "Audit only" enforcement mode reports that an Application, DLL, Script, MSI, or Packaged-App would have been blocked if AppLocker "Enforce rules" enforcement mode was enabled.	Generic	experimental	-	windows	AppLocker	Execution Command and Scripting Interpreter PowerShell Windows Command Shell Visual Basic Python Execution User Execution Malicious File	-	medium	heyyanu	2026-03-26	—	557e3bd3-7f21-495d-8d50-7c8bdfb8041c
	Detects when AppLocker prevents the execution of an Application, DLL, Script, MSI, or Packaged-App from running.	Generic	test	-	windows	AppLocker	Execution Command and Scripting Interpreter PowerShell Windows Command Shell Visual Basic Python Execution User Execution Malicious File	-	medium	Pushkarev Dmitry	2020-06-28	2025-12-03	401e5d00-b944-11ea-8f9a-00163ecd60ae
	Detects changes to the EC2 instance startup script. (...)	Generic	test	cloud_audit	-	AWS CloudTrail · AWS	Execution Command and Scripting Interpreter PowerShell Windows Command Shell Unix Shell	-	high	faloker	2020-02-12	2022-06-07	1ab3c5ed-5baf-417b-bb6b-78ca33f6c3df
	Detects the specific Windows execution chain and process tree associated with the Axios NPM supply chain compromise. (...)	Emerging	experimental	process_creation	windows	Sysmon · WinEventLog Security	Execution Command and Scripting Interpreter Windows Command Shell Visual Basic Command and Control Ingress Tool Transfer Initial Access Supply Chain Compromise Compromise Software Supply Chain	-	high	Swachchhanda Shrawan Poudel (Nextron Systems)	2026-04-01	—	f6c27ecc-d890-4452-80e6-2e274a10e097
Splunk	The following analytic detects the use of `cmd.exe /c` to execute commands, a technique often employed by adversaries and malware to run batch commands or invoke other shells like PowerShell. (...)	Hunting	stable	process_creation	windows	Sysmon · WinEventLog Security · CrowdStrike	Execution Command and Scripting Interpreter Windows Command Shell	CVE-2021-44228	medium	Teoderick Contreras, Bhavin Patel, Splunk	2021-10-21	2026-05-13	54a6ed00-3256-11ec-b031-acde48001122
Splunk	The following analytic identifies the use of named-pipe impersonation for privilege escalation, commonly associated with Cobalt Strike and similar frameworks. (...)	Generic	stable	process_creation	windows	Sysmon · WinEventLog Security · CrowdStrike	Execution Command and Scripting Interpreter Windows Command Shell Persistence, Privilege Escalation Create or Modify System Process Windows Service	-	medium	Michael Haag, Splunk	2021-05-27	2026-05-13	eb277ba0-b96b-11eb-b00e-acde48001122
	Detects a suspicious command line execution that includes an URL and AppData string in the command l (...)	Generic	test	process_creation	windows	Sysmon · WinEventLog Security	Execution Command and Scripting Interpreter PowerShell Windows Command Shell Command and Control Ingress Tool Transfer	-	medium	Florian Roth (Nextron Systems), Jonhnathan Ribeiro, oscd.community	2019-01-16	2021-11-27	1ac8666b-046f-4201-8aba-1951aaec03a3
	detects the usage of path traversal in conhost.exe indicating possible command/argument confusion/hi (...)	Generic	test	process_creation	windows	Sysmon · WinEventLog Security	Execution Command and Scripting Interpreter Windows Command Shell	-	high	Nasreddine Bencherchali (Nextron Systems)	2022-06-14	—	ee5e119b-1f75-4b34-add8-3be976961e39
Splunk	The following analytic detects potential exploitation of the CrushFTP authentication bypass vulnerability (CVE-2025-31161). (...)	Generic	stable	file_event	-	CrushFTP	Execution Command and Scripting Interpreter PowerShell Windows Command Shell Initial Access Exploit Public-Facing Application	CVE-2025-31161	medium	Michael Haag, Splunk	2025-04-14	2026-09-08	82eb7f64-d219-4e21-acfe-956de84c1a35
Splunk	The following analytic detects executions of cmd.exe spawned by processes that are commonly abused by attackers and do not typically launch cmd.exe. (...)	Hunting	stable	process_creation	windows	Sysmon · WinEventLog Security · CrowdStrike	Execution Command and Scripting Interpreter Windows Command Shell	-	medium	Bhavin Patel, Splunk	2020-04-29	2026-05-13	dcfd6b40-42f9-469d-a433-2e53f7486664	-
Splunk	The following detects the execution of cscript.exe or wscript.exe processes spawned by cmd.exe, leveraging Endpoint Detection and Response (EDR) telemetry mapped to the Endpoint data model, with additional contextual filtering to improve fidelity and reduce false positives. (...)	Anomaly	stable	process_creation	windows	Sysmon · WinEventLog Security · CrowdStrike	Execution Command and Scripting Interpreter Windows Command Shell	-	medium	Bhavin Patel, Mauricio Velazco, Splunk	2020-04-29	2026-05-13	b89919ed-fe5f-492c-b139-95dbb162039e
	Detects DNS queries made by the finger utility, which can be abused by threat actors to retrieve remote commands for execution on Windows devices. (...)	Generic	experimental	dns	windows	Sysmon	Command and Control Application Layer Protocol DNS Execution Command and Scripting Interpreter Windows Command Shell	-	high	Swachchhanda Shrawan Poudel (Nextron Systems)	2025-11-19	—	c082c2b0-525b-4dbc-9a26-a57dc4692074
	Detects Elise backdoor activity used by APT32	Emerging	test	process_creation	windows	Sysmon · WinEventLog Security	Execution Command and Scripting Interpreter Windows Command Shell	-	critical	Florian Roth (Nextron Systems), Nasreddine Bencherchali (Nextron Systems)	2018-01-31	2023-03-09	e507feb7-5f73-4ef6-a970-91bb6f6d744f
	Detects the exploitation of Zoho ManageEngine Desktop Central Java Deserialization vulnerability rep (...)	Emerging	test	process_creation	windows	Sysmon · WinEventLog Security	Execution Command and Scripting Interpreter PowerShell Windows Command Shell Initial Access Exploit Public-Facing Application	CVE-2020-10189	high	Florian Roth (Nextron Systems)	2020-03-25	2023-01-21	846b866e-2a57-46ee-8e16-85fa92759be7
	Detects exploitation attempt of privilege escalation vulnerability via SetupComplete.cmd and Partner (...)	Emerging	test	process_creation	windows	Sysmon · WinEventLog Security	Execution Command and Scripting Interpreter Windows Command Shell Privilege Escalation Exploitation for Privilege Escalation Execution, Stealth Hijack Execution Flow	CVE-2019-1378	high	Florian Roth (Nextron Systems), oscd.community, Jonhnathan Ribeiro	2019-11-15	2021-11-27	1c373b6d-76ce-4553-997d-8c1da9a6b5f5
	Detects GitHub self-hosted runners executing workflows on local infrastructure that could be abused for persistence and code execution. (...)	Generic	test	process_creation	windows	Sysmon · WinEventLog Security	Command and Control Application Layer Protocol Command and Control Web Service Bidirectional Communication	-	medium	Daniel Koifman (KoifSec)	2025-11-29	—	5bac7a56-da88-4c27-922e-c81e113b20cb
	This rule detect common flag combinations used by CrackMapExec in order to detect its use even if the binary has been replaced.	Generic	test	process_creation	windows	Sysmon · WinEventLog Security	Credential Access Brute Force Execution Command and Scripting Interpreter PowerShell Windows Command Shell Discovery Password Policy Discovery Execution, Persistence, Privilege Escalation Scheduled Task/Job Execution Windows Management Instrumentation	-	high	Florian Roth (Nextron Systems)	2022-02-25	2023-03-08	42a993dd-bb3e-48c8-b372-4d6684c4106c
	Detects various execution patterns of the CrackMapExec pentesting framework	Generic	stable	process_creation	windows	Sysmon · WinEventLog Security	Execution Command and Scripting Interpreter PowerShell Windows Command Shell Execution, Persistence, Privilege Escalation Scheduled Task/Job Execution Windows Management Instrumentation	-	high	Thomas Patzke	2020-05-22	2023-11-06	058f4380-962d-40a5-afce-50207d36d7e2
	Detects the use of Jlaive to execute assemblies in a copied PowerShell	Generic	test	process_creation	windows	Sysmon · WinEventLog Security	Execution Command and Scripting Interpreter Windows Command Shell	-	medium	Jose Luis Sanchez Martinez (@Joseliyo_Jstnk)	2022-05-24	2023-02-22	0a99eb3e-1617-41bd-b095-13dc767f3def
	Detects command line parameters used by Koadic hack tool	Generic	test	process_creation	windows	Sysmon · WinEventLog Security	Execution Command and Scripting Interpreter Windows Command Shell Visual Basic JavaScript	-	high	wagga, Jonhnathan Ribeiro, oscd.community	2020-01-12	2023-02-11	5cddf373-ef00-4112-ad72-960ac29bac34
	Detects actions caused by the RedMimicry Winnti playbook a automated breach emulations utility	Generic	test	process_creation	windows	Sysmon · WinEventLog Security	Execution Command and Scripting Interpreter Windows Command Shell Execution Native API Stealth System Binary Proxy Execution Rundll32	-	high	Alexander Rausch	2020-06-24	2023-03-01	95022b85-ff2a-49fa-939a-d7b8f56eeb9b
	Detects the launch of a child process via "conhost.exe" with the "--headless" flag. (...)	Hunting	test	process_creation	windows	Sysmon · WinEventLog Security	Execution Command and Scripting Interpreter PowerShell Windows Command Shell	-	medium	Nasreddine Bencherchali (Nextron Systems)	2024-07-23	—	00ca75ab-d5ce-43be-b86c-55ff39c6abfc
	Detects a suspicious child process of a Microsoft HTML Help (HH.exe)	Generic	test	process_creation	windows	Sysmon · WinEventLog Security	Execution Command and Scripting Interpreter PowerShell Windows Command Shell Visual Basic JavaScript Initial Access Phishing Spearphishing Attachment Stealth System Binary Proxy Execution Compiled HTML File Regsvr32 Rundll32 Execution Windows Management Instrumentation	-	high	Maxim Pavlunin, Nasreddine Bencherchali (Nextron Systems)	2020-04-01	2023-04-12	52cad028-0ff0-4854-8f67-d25dfcbc78b4
	Detects network connections via finger.exe, which can be abused by threat actors to retrieve remote commands for execution on Windows devices. (...)	Generic	experimental	network_connection	windows	Sysmon	Command and Control Application Layer Protocol DNS Execution Command and Scripting Interpreter Windows Command Shell	-	high	Swachchhanda Shrawan Poudel (Nextron Systems)	2025-11-19	—	2fdaf50b-9fd5-449f-ba69-f17248119af6
	Detects the OpenEDR ssh-shellhost.exe spawning a command shell (cmd.exe) or PowerShell with PTY (pseudo-terminal) capabilities. (...)	Generic	experimental	process_creation	windows	Sysmon · WinEventLog Security	Execution Command and Scripting Interpreter Windows Command Shell Command and Control Remote Access Tools Lateral Movement Remote Services SSH	-	medium	@kostastsale	2026-02-19	—	7f3a9c2d-4e8b-4a7f-9d3e-5c6f8a9b2e1d
	Detects use of Cobalt Strike commands accidentally entered in the CMD shell	Generic	test	process_creation	windows	Sysmon · WinEventLog Security	Execution Command and Scripting Interpreter Windows Command Shell	-	high	_pete_0, TheDFIRReport	2022-05-06	2023-01-30	647c7b9e-d784-4fda-b9a0-45c565a7b729
	Detects Cobalt Strike module/commands accidentally entered in CMD shell	Generic	test	process_creation	windows	Sysmon · WinEventLog Security	Execution Command and Scripting Interpreter Windows Command Shell	-	high	_pete_0, TheDFIRReport	2022-05-06	2023-01-30	4f154fb6-27d1-4813-a759-78b93e0b9c48
	Detects potential APT FIN7 exploitation activity as reported by Google. (...)	Emerging	test	process_creation	windows	Sysmon · WinEventLog Security	Execution Command and Scripting Interpreter PowerShell Windows Command Shell	-	medium	Alex Walston (@4ayymm)	2024-07-29	—	6676896b-2cce-422d-82af-5a1abe65e241
	Detects activity that could be related to Baby Shark malware	Emerging	test	process_creation	windows	Sysmon · WinEventLog Security	Execution Command and Scripting Interpreter PowerShell Windows Command Shell Discovery Query Registry Stealth System Binary Proxy Execution Mshta	-	high	Florian Roth (Nextron Systems)	2019-02-24	2023-03-08	2b30fa36-3a18-402f-a22d-bf4ce2189f35
	Detects potential path traversal attempt via cmd.exe. (...)	Generic	test	process_creation	windows	Sysmon · WinEventLog Security	Execution Command and Scripting Interpreter Windows Command Shell	-	high	xknow @xknow_infosec, Tim Shelton	2020-06-11	2023-03-06	087790e3-3287-436c-bccf-cbd0184a7db1
	Detects suspicious child processes created by CrushFTP. (...)	Emerging	experimental	process_creation	windows	Sysmon · WinEventLog Security	Execution Command and Scripting Interpreter PowerShell Windows Command Shell Initial Access Exploit Public-Facing Application Privilege Escalation Exploitation for Privilege Escalation	CVE-2025-54309	high	Nisarg Suthar	2025-08-01	—	0fdc7c7f-c690-4217-9ae3-31f5156eed72
	Detects the execution of concatenated commands via "cmd.exe". (...)	Emerging	test	process_creation	windows	Sysmon · WinEventLog Security	Execution Command and Scripting Interpreter Windows Command Shell Command and Control Ingress Tool Transfer Stealth System Binary Proxy Execution	-	medium	Alejandro Houspanossian ('@lekz86')	2024-01-02	—	e5144106-8198-4f6e-bfc2-0a551cc8dd94
	Detects the creation of suspicious files (jsp, java, class) in SAP NetWeaver directories, which may (...)	Emerging	experimental	file_event	windows	Sysmon	Execution Command and Scripting Interpreter Windows Command Shell Initial Access Exploit Public-Facing Application	CVE-2025-31324	medium	Elastic (idea), Swachchhanda Shrawan Poudel (Nextron Systems)	2025-04-28	—	86a7c91f-98c3-4f14-a58d-d989421e1234
	Detects the creation of suspicious files (jsp, java, class) in SAP NetWeaver directories, which may (...)	Emerging	experimental	file_event	linux	Sysmon	Execution Command and Scripting Interpreter Windows Command Shell Initial Access Exploit Public-Facing Application	CVE-2025-31324	medium	Elastic (idea), Swachchhanda Shrawan Poudel (Nextron Systems)	2025-04-28	—	5b91409c-cb18-4ab6-ac75-c5759f998409
Splunk	The following analytic detects the presence of "api.telegram.org" in the CommandLine of a process. (...)	Anomaly	stable	process_creation	windows	Sysmon · WinEventLog Security · CrowdStrike	Exfiltration Exfiltration Over C2 Channel Command and Control Web Service Bidirectional Communication	-	medium	Nasreddine Bencherchali, Splunk, Zaki Zarkasih Al Mustafa	2025-02-19	2026-05-13	d6b0d627-d0bf-46b1-936f-c48284767d21
	Detects connections with Azure Front Door (known legitimate service that can be leveraged for C2) th (...)	Hunting	test	network_connection	windows	Sysmon	Command and Control Proxy Domain Fronting Command and Control Web Service Bidirectional Communication	-	medium	Isaac Dunham	2024-11-07	—	8cb4d14e-776e-43c2-8fb9-91e7fcea32b4
	Adversaries may abuse the Windows command shell for execution. (...)	Generic	test	ps_script	windows	PowerShell	Execution Command and Scripting Interpreter Windows Command Shell	-	medium	frack113	2022-01-02	—	b5522a23-82da-44e5-9c8b-e10ed8955f88
	Detects the use of powershell commands from headless ConHost window. (...)	Generic	test	process_creation	windows	Sysmon · WinEventLog Security	Execution Command and Scripting Interpreter PowerShell Windows Command Shell Stealth Hide Artifacts Hidden Window	-	medium	Matt Anderson (Huntress)	2024-07-23	—	056c7317-9a09-4bd4-9067-d051312752ea
	Detects the execution of AdvancedRun utility	Generic	test	process_creation	windows	Sysmon · WinEventLog Security	Privilege Escalation, Stealth Access Token Manipulation Create Process with Token Execution Command and Scripting Interpreter Windows Command Shell Stealth Hide Artifacts Hidden Window	-	medium	Florian Roth (Nextron Systems)	2022-01-20	2023-02-21	d2b749ee-4225-417e-b20e-a8d2193cbb84
	Detect the use of "<" to read and potentially execute a file via cmd.exe	Generic	test	process_creation	windows	Sysmon · WinEventLog Security	Execution Command and Scripting Interpreter Windows Command Shell	-	medium	frack113, Nasreddine Bencherchali (Nextron Systems)	2023-03-07	—	241e802a-b65e-484f-88cd-c2dc10f9206d
	Detects command execution via ScreenConnect RMM	Generic	test	-	windows	WinEventLog Application	Execution Command and Scripting Interpreter Windows Command Shell	-	low	Ali Alwashali	2023-10-10	—	076ebe48-cc05-4d8f-9d41-89245cd93a14
	Detects file being transferred via ScreenConnect RMM	Generic	test	-	windows	WinEventLog Application	Execution Command and Scripting Interpreter Windows Command Shell	-	low	Ali Alwashali	2023-10-10	—	5d19eb78-5b5b-4ef2-a9f0-4bfa94d58a13
	Detects the execution of a system command via the ScreenConnect RMM service.	Generic	test	process_creation	windows	Sysmon · WinEventLog Security	Execution Command and Scripting Interpreter Windows Command Shell	-	low	Ali Alwashali	2023-10-10	2024-02-26	b1f73849-6329-4069-bc8f-78a604bb8b23
	Detects the creation of files in a specific location by ScreenConnect RMM. (...)	Generic	test	file_event	windows	Sysmon	Execution Command and Scripting Interpreter Windows Command Shell	-	low	Ali Alwashali	2023-10-10	—	0afecb6e-6223-4a82-99fb-bf5b981e92a5
	Detects Rorschach ransomware execution activity	Emerging	test	process_creation	windows	Sysmon · WinEventLog Security	Execution Command and Scripting Interpreter PowerShell Windows Command Shell	-	critical	X__Junior (Nextron Systems)	2023-04-04	2023-04-22	0e9e6c63-1350-48c4-9fa1-7ccb235edc68
Splunk	The following analytic detects the use of Wake-on-LAN commands associated with Ryuk ransomware. (...)	Generic	stable	process_creation	windows	Sysmon · WinEventLog Security · CrowdStrike	Execution Command and Scripting Interpreter Windows Command Shell	-	medium	Michael Haag, Splunk	2021-03-01	2026-05-13	538d0152-7aaa-11eb-beaa-acde48001122
	Detects Trojan loader activity as used by APT28	Emerging	test	process_creation	windows	Sysmon · WinEventLog Security	Execution Command and Scripting Interpreter Windows Command Shell Stealth System Binary Proxy Execution Rundll32	-	high	Florian Roth (Nextron Systems), Jonhnathan Ribeiro, oscd.community	2018-03-01	2023-05-31	ba778144-5e3d-40cf-8af9-e28fb1df1e20
	Detects suspicious child processes spawned by SAP NetWeaver that could indicate potential exploitati (...)	Emerging	experimental	process_creation	windows	Sysmon · WinEventLog Security	Execution Command and Scripting Interpreter Windows Command Shell Initial Access Exploit Public-Facing Application	CVE-2025-31324	medium	Elastic (idea), Swachchhanda Shrawan Poudel (Nextron Systems)	2025-04-28	—	5b304bcb-ac33-49d0-87af-fa1b3ca94333
	Detects suspicious child processes spawned by SAP NetWeaver on Linux systems that could indicate pot (...)	Emerging	experimental	process_creation	linux	Sysmon	Execution Command and Scripting Interpreter Windows Command Shell Initial Access Exploit Public-Facing Application	CVE-2025-31324	medium	Elastic (idea), Swachchhanda Shrawan Poudel (Nextron Systems)	2025-04-28	—	69dea60b-2deb-4c9e-a685-ad542f4367f9
	Detects suspicious child processes spawned by the CrushFTP service that may indicate exploitation of (...)	Emerging	experimental	process_creation	windows	Sysmon · WinEventLog Security	Execution Command and Scripting Interpreter PowerShell Windows Command Shell Initial Access Exploit Public-Facing Application	CVE-2025-2825 CVE-2025-31161	medium	Craig Sweeney, Matt Anderson, Jose Oregon, Tim Kasper, Faith Stratton, Samantha Shaw, Swachchhanda Shrawan Poudel (Nextron Systems)	2025-04-10	—	459628e3-1b00-4e9b-9e5b-7da8961aea35