malware

CASTLETAP S1224

Type: malware
Platform: Network Devices
Created: 16 June 2025
Last modified: 16 June 2025

CASTLETAP is an ICMP port knocking backdoor that has been installed on compromised FortiGate firewalls by UNC3886.[1]

Techniques38th pct

Tactics68th pct

Threat groupunranked

CampaignsNone recorded

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

Standing S1224

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.

Select	Description	Category	Status	Event	OS	Product	MITRE ATT&CK	CVEs	Severity	Author	Created	Updated	ID	Refs
	Detects suspicious local connections via a named pipe to the AD FS configuration database (Windows Internal Database). (...)	Generic	test	pipe_created	windows	Sysmon	Collection Data from Local System	-	medium	Roberto Rodriguez @Cyb3rWard0g	2021-10-08	2023-11-30	1ea13e8c-03ea-409b-877d-ce5c3d2c1cb3
	Detects DNS queries made by "AppInstaller.EXE". (...)	Generic	test	dns	windows	Sysmon	Command and Control Ingress Tool Transfer	-	medium	frack113	2021-11-24	2023-11-09	7cff77e1-9663-46a3-8260-17f2e1aa9d0a
	Detects execution of GfxDownloadWrapper.exe with a URL as an argument to download file.	Generic	test	process_creation	windows	Sysmon · WinEventLog Security	Command and Control Ingress Tool Transfer	-	medium	Victor Sergeev, oscd.community	2020-10-09	2023-10-18	eee00933-a761-4cd0-be70-c42fe91731e7
	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
	An attempt to export an AWS EC2 instance has been detected. (...)	Generic	test	cloud_audit	-	AWS CloudTrail · AWS	Collection Data from Local System Exfiltration Transfer Data to Cloud Account	-	low	Diogo Braz	2020-04-16	2022-10-05	54b9a76a-3c71-4673-b4b3-2edb4566ea7b
	Detects file creation events linked to the Axios NPM supply chain compromise. (...)	Emerging	experimental	file_event	linux	Sysmon	Command and Control Ingress Tool Transfer Initial Access Supply Chain Compromise Compromise Software Supply Chain	-	high	Swachchhanda Shrawan Poudel (Nextron Systems)	2026-04-01	—	b7cb840c-11f6-47f7-b3ef-5524739c9077
	Detects file creation events linked to the Axios NPM supply chain compromise on macOS devices. (...)	Emerging	experimental	file_event	macos	-	Command and Control Ingress Tool Transfer Initial Access Supply Chain Compromise Compromise Software Supply Chain	-	high	Swachchhanda Shrawan Poudel (Nextron Systems)	2026-04-01	—	2db0458c-05c9-4069-a26f-77becd9c8c13
	Detects the Linux-specific execution chain of the plain-crypto-js malicious npm dependency by Axios NPM package, including payload download via curl and detached execution using nohup and python3. (...)	Emerging	experimental	process_creation	linux	Sysmon	Execution Command and Scripting Interpreter Unix Shell Python Command and Control Ingress Tool Transfer Initial Access Supply Chain Compromise Compromise Software Supply Chain	-	high	Swachchhanda Shrawan Poudel (Nextron Systems)	2026-04-01	—	0a23a62d-c5b3-468b-a072-25064a9a8c87
	Detects the macOS-specific execution chain of the plain-crypto-js malicious npm dependency in Axios NPM Package, including AppleScript execution via osascript, payload download, permission modification, execution, and cleanup.	Emerging	experimental	process_creation	macos	-	Execution Command and Scripting Interpreter AppleScript Unix Shell Command and Control Ingress Tool Transfer Initial Access Supply Chain Compromise Compromise Software Supply Chain	-	high	Swachchhanda Shrawan Poudel (Nextron Systems)	2026-04-01	—	a09ee860-31b3-4586-8a68-0ebd74ce0e5f
	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
	Detects usage of the "FromBase64String" function in the commandline which is used to decode a base64 (...)	Generic	test	process_creation	windows	Sysmon · WinEventLog Security	Execution Command and Scripting Interpreter PowerShell Stealth Deobfuscate/Decode Files or Information Stealth Obfuscated Files or Information	-	high	Florian Roth (Nextron Systems)	2020-01-29	2023-01-26	e32d4572-9826-4738-b651-95fa63747e8a
Splunk	The following analytic detects the use of `bitsadmin.exe` with the `transfer` parameter to download a remote object. (...)	Generic	stable	process_creation	windows	Sysmon · WinEventLog Security · CrowdStrike	Execution, Persistence, Stealth BITS Jobs Command and Control Ingress Tool Transfer	-	medium	Michael Haag, Sittikorn S	2021-03-30	2026-10-02	80630ff4-8e4c-11eb-aab5-acde48001122
	Detects the usage of the unsafe bpftrace option	Generic	test	process_creation	linux	Sysmon	Execution Command and Scripting Interpreter Unix Shell	-	medium	Andreas Hunkeler (@Karneades)	2022-02-11	—	f8341cb2-ee25-43fa-a975-d8a5a9714b39
	Detects execution of Chromium based browser in headless mode	Generic	test	process_creation	windows	Sysmon · WinEventLog Security	Stealth Hide Artifacts Hidden Window Command and Control Ingress Tool Transfer	-	low	Nasreddine Bencherchali (Nextron Systems)	2023-09-12	—	ef9dcfed-690c-4c5d-a9d1-482cd422225c
Splunk	The following analytic detects the use of CertUtil.exe with the 'decode' argument, which may indicate an attempt to decode a previously encoded file, potentially containing malicious payloads. (...)	Generic	stable	process_creation	windows	Sysmon · WinEventLog Security · CrowdStrike	Stealth Deobfuscate/Decode Files or Information	-	medium	Michael Haag, Splunk	2021-03-25	2026-10-02	bfe94226-8c10-11eb-a4b3-acde48001122
Splunk	This analytic detects file copy activity on Cisco ASA devices via CLI or ASDM. (...)	Anomaly	stable	firewall	-	Cisco Secure Firewall · Cisco	Collection Data from Cloud Storage Collection Data from Local System	-	medium	Nasreddine Bencherchali, Splunk	2025-11-21	2026-05-13	4d7e8f3a-9c2b-4e6f-8a1d-5b9c7e2f4a8c
Splunk	This analytic detects file copy operations to remote locations on Cisco ASA devices via CLI or ASDM. (...)	Anomaly	stable	firewall	-	Cisco Secure Firewall · Cisco	Collection Data from Local System Exfiltration Exfiltration Over Alternative Protocol Exfiltration Over Unencrypted Non-C2 Protocol Exfiltration Exfiltration Over C2 Channel	-	medium	Nasreddine Bencherchali, Splunk	2025-11-21	2026-05-13	8a9e5f2b-6d4c-4e7f-9b3a-1c8d7f5e2a9b
Splunk	This analytic detects execution of packet capture commands on Cisco ASA devices via CLI or ASDM. (...)	Anomaly	stable	firewall	-	Cisco Secure Firewall · Cisco	Credential Access, Collection Adversary-in-the-Middle Credential Access, Discovery Network Sniffing	-	medium	Nasreddine Bencherchali, Splunk	2025-11-21	2026-05-13	7e9c3f8a-4b2d-4c5e-9a1f-6d8e5b3c2a9f
	Collect pertinent data from the configuration files	Generic	test	authentication	-	Cisco AAA · Cisco	Discovery Account Discovery Local Account Collection Data from Local System Credential Access Unsecured Credentials Credentials In Files	-	low	Austin Clark	2019-08-11	2023-01-04	cd072b25-a418-4f98-8ebc-5093fb38fe1a
Splunk	The following analytic detects the execution of curl commands with insecure flags within the Cisco Isovalent environment. (...)	Anomaly	stable	process_creation	-	Cisco	Command and Control Ingress Tool Transfer	-	medium	Bhavin Patel, Splunk	2026-01-05	2026-10-02	c16c4899-d3f7-461b-92c2-cc0ef5758855
Splunk	This analytic identifies the use of Chromium-based browsers (like Microsoft Edge) running in headless mode with the `--dump-dom` argument. (...)	Generic	stable	network_connection	-	Cisco NVM · Cisco	Execution Command and Scripting Interpreter Command and Control Ingress Tool Transfer	-	medium	Nasreddine Bencherchali, Splunk	2025-07-01	2026-09-22	cd0e816f-f67d-4dbe-a153-480b546e867e
Splunk	This analytic detects unexpected outbound network connections initiated by known webserver processes such as `httpd.exe`, `nginx.exe`, or `tomcat.exe` to common file sharing or public content hosting services like GitHub, Discord CDN, Transfer.sh, or Pastebin. (...)	Generic	stable	network_connection	-	Cisco NVM · Cisco	Initial Access Exploit Public-Facing Application Command and Control Ingress Tool Transfer	-	medium	Nasreddine Bencherchali, Splunk	2025-07-01	2026-09-22	1984f997-3b49-4d4b-a7e9-dc5dbf88370e
Splunk	The following analytic detects the use of known suspicious SSL certificates in any observed event where the SSL_CertFingerprint field is present. (...)	Generic	stable	firewall	-	Cisco Secure Firewall · Cisco	Command and Control Application Layer Protocol Web Protocols Resource Development Develop Capabilities Code Signing Certificates Command and Control Encrypted Channel Asymmetric Cryptography Resource Development Obtain Capabilities Digital Certificates	-	medium	Nasreddine Bencherchali, Splunk	2025-04-03	2026-09-22	c43f7b49-2dab-4e76-892e-7f971c2f20f1
Splunk	The following analytic detects potential reverse shell activity by identifying connections involving ports commonly associated with remote access tools, shell listeners, or tunneling utilities. (...)	Anomaly	stable	firewall	-	Cisco Secure Firewall · Cisco	Execution Command and Scripting Interpreter PowerShell Command and Control Ingress Tool Transfer Command and Control Non-Standard Port Privilege Escalation, Stealth Process Injection Command and Control Remote Access Tools Lateral Movement Remote Services	-	medium	Nasreddine Bencherchali, Splunk	2025-04-03	2026-05-13	d85c05c8-42c0-4e4a-87e7-4e1bb3e844e3
Splunk	The following analytic detects outbound connections to commonly abused file sharing and pastebin-style hosting domains. (...)	Anomaly	stable	firewall	-	Cisco Secure Firewall · Cisco	Command and Control Application Layer Protocol Web Protocols Exfiltration Exfiltration Over Web Service Exfiltration to Cloud Storage Command and Control Ingress Tool Transfer Resource Development Obtain Capabilities Tool Command and Control Proxy External Proxy	-	medium	Nasreddine Bencherchali, Splunk	2025-04-03	2026-05-13	f7e5e792-d907-46c1-a58e-4ff974dc462a
Splunk	The following analytic detects file transfers flagged as malware that occurred over non-standard ports (other than 80 and 443). (...)	Anomaly	stable	firewall	-	Cisco Secure Firewall · Cisco	Command and Control Ingress Tool Transfer Command and Control Non-Standard Port	-	medium	Nasreddine Bencherchali, Splunk	2025-04-09	2026-09-22	f26445a8-a6a2-4855-bec0-0c39e52e5b8f
Splunk	The following analytic detects connections with a high Encrypted Visibility Engine (EVE) threat confidence score, indicating potentially malicious behavior within encrypted traffic. (...)	Anomaly	stable	firewall	-	Cisco Secure Firewall · Cisco	Command and Control Application Layer Protocol Web Protocols Command and Control Encrypted Channel Asymmetric Cryptography Exfiltration Exfiltration Over C2 Channel Command and Control Ingress Tool Transfer	-	medium	Nasreddine Bencherchali, Splunk	2025-04-03	2026-05-13	8c15183e-2e70-4db4-86c3-88f8d9129b66
Splunk	This analytic detects intrusion events from known threat activity using Cisco Secure Firewall Intrusion Events. (...)	Anomaly	stable	firewall	-	Cisco Secure Firewall · Cisco	Command and Control Encrypted Channel Asymmetric Cryptography Exfiltration Exfiltration Over C2 Channel	-	medium	Bhavin Patel, Nasreddine Bencherchali, Splunk	2025-05-12	2026-09-22	b71e57e8-c571-4ff1-ae13-bc4384a9e891
Splunk	This analytic detects Lumma Stealer download attempts using Cisco Secure Firewall Intrusion Events. (...)	Anomaly	stable	firewall	-	Cisco Secure Firewall · Cisco	Command and Control Encrypted Channel Asymmetric Cryptography Exfiltration Exfiltration Over C2 Channel	-	medium	Nasreddine Bencherchali, Splunk, Talos NTDR	2025-04-16	2026-05-13	66f22f52-fbae-4be7-a263-561dacb63613
Splunk	This analytic detects Lumma Stealer outbound connection attempts using Cisco Secure Firewall Intrusion Events. (...)	Anomaly	stable	firewall	-	Cisco Secure Firewall · Cisco	Command and Control Encrypted Channel Asymmetric Cryptography Exfiltration Exfiltration Over C2 Channel	-	medium	Nasreddine Bencherchali, Splunk, Talos NTDR	2025-04-16	2026-05-13	66f22f52-fbae-4be7-a263-561dacb63612
Splunk	The following analytic detects file downloads that were classified as malware by Cisco Secure Firewall Threat Defense. (...)	Anomaly	stable	firewall	-	Cisco Secure Firewall · Cisco	Execution Exploitation for Client Execution Command and Control Ingress Tool Transfer	-	medium	Nasreddine Bencherchali, Splunk	2025-04-09	2026-09-22	3cc93f52-5aa6-4b7f-83b9-3430b1436813
Splunk	The following analytic detects repeated malware file downloads initiated by the same internal host (src) within a short time window. (...)	Anomaly	stable	firewall	-	Cisco Secure Firewall · Cisco	Command and Control Ingress Tool Transfer Stealth Obfuscated Files or Information	-	medium	Nasreddine Bencherchali, Splunk	2025-04-09	2026-09-22	aeff2bb5-3483-48d4-9be8-c8976194be1e
Splunk	This analytic identifies Snort intrusion signatures that have been triggered by ten or more distinct internal IP addresses within a one-hour window. (...)	Anomaly	stable	firewall	-	Cisco Secure Firewall · Cisco	Command and Control Ingress Tool Transfer Stealth Obfuscated Files or Information	-	medium	Nasreddine Bencherchali, Splunk	2025-04-16	2026-05-13	a4c76d0a-56b6-44be-814b-939746c4d406
Splunk	The following analytic detects outbound connections initiated by command-line tools such as curl or wget. (...)	Anomaly	stable	firewall	-	Cisco Secure Firewall · Cisco	Command and Control Application Layer Protocol Web Protocols Execution Command and Scripting Interpreter Command and Control Ingress Tool Transfer Execution, Persistence, Privilege Escalation Scheduled Task/Job Cron	-	medium	Nasreddine Bencherchali, Splunk	2025-04-03	2026-05-13	173a1cb9-1814-4128-a9dc-f29dade89957
	Show when a monitor or a span/rspan is setup or modified	Generic	test	authentication	-	Cisco AAA · Cisco	Credential Access, Discovery Network Sniffing	-	medium	Austin Clark	2019-08-11	2023-01-04	b9e1f193-d236-4451-aaae-2f3d2102120d	-
Splunk	This analytic detects changes to SNMP community strings on Cisco devices, which could indicate an attacker establishing persistence or attempting to extract credentials. (...)	Anomaly	stable	configuration_change	-	Cisco IOS · Cisco	Defense Impairment Disable or Modify Tools Credential Access, Discovery Network Sniffing Credential Access Unsecured Credentials	CVE-2018-0171	medium	Bhavin Patel, Michael Haag, Splunk	2025-08-21	2026-05-13	b0ce5521-2533-4f24-b8d5-c2ff977aae08
	Various protocols maybe used to put data on the device for exfil or infil	Generic	test	authentication	-	Cisco AAA · Cisco	Collection Archive Collected Data Archive via Utility Collection Data Staged Command and Control Ingress Tool Transfer	-	low	Austin Clark	2019-08-12	2023-01-04	5e51acb2-bcbe-435b-99c6-0e3cd5e2aa59	-
Splunk	This analytic detects the configuration of TFTP services on Cisco IOS devices that could be used to exfiltrate sensitive configuration files. (...)	Generic	stable	configuration_change	-	Cisco IOS · Cisco	Collection Data from Local System Exfiltration Exfiltration Over Web Service	CVE-2018-0171	medium	Bhavin Patel, Michael Haag, Splunk	2025-08-21	2026-05-13	1abce487-f480-4d5f-a551-01de0bece0bd
	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 "BugCheck" errors indicating the system rebooted due to a crash, capturing the bugcheck code, dump file path, and report ID.	Generic	experimental	-	windows	WinEventLog System	Collection Data from Local System Credential Access OS Credential Dumping Security Account Manager	-	medium	Jason Mull	2025-05-12	—	882fbe50-d8d7-4e29-ae80-0648a8556866
	Adversaries can use curl to download payloads remotely and execute them. (...)	Generic	test	process_creation	windows	Sysmon · WinEventLog Security	Command and Control Ingress Tool Transfer Stealth System Binary Proxy Execution	-	high	Sreeman, Nasreddine Bencherchali (Nextron Systems)	2020-01-13	2024-03-05	21dd6d38-2b18-4453-9404-a0fe4a0cc288
Splunk	The following analytic detects the execution of the curl utility where the command line includes percent-encoded characters and explicit file output options (such as -o or --output). (...)	Anomaly	stable	process_creation	windows · linux	CrowdStrike · Sysmon · WinEventLog Security	Command and Control Ingress Tool Transfer Stealth Obfuscated Files or Information	-	medium	Nasreddine Bencherchali, Splunk	2026-03-03	2026-05-13	9a8d5516-4c5e-11ef-9d42-acde48001122
	Detects a curl process start on linux, which indicates a file download from a remote location or a s (...)	Generic	test	process_creation	linux	Sysmon	Command and Control Ingress Tool Transfer	-	low	Nasreddine Bencherchali (Nextron Systems)	2022-09-15	—	ea34fb97-e2c4-4afb-810f-785e4459b194
	Detects a curl process start on Windows, which could indicates a file download from a remote locatio (...)	Hunting	test	process_creation	windows	Sysmon · WinEventLog Security	Command and Control Ingress Tool Transfer	-	low	Florian Roth (Nextron Systems)	2022-07-05	2023-02-21	bbeaed61-1990-4773-bf57-b81dbad7db2d
	Detects the usage of curl.exe, KeyScramblerLogon, or other non-standard/suspicious processes used to create Autoit3.exe. (...)	Emerging	test	file_event	windows	Sysmon	Execution Command and Scripting Interpreter Command and Control Ingress Tool Transfer	-	medium	Micah Babinski	2023-10-15	—	1a433e1d-03d2-47a6-8063-ece992cf4e73
Splunk	The following analytic detects the use of Certify or Certipy tools to enumerate Active Directory Certificate Services (AD CS) environments. (...)	Generic	stable	process_creation	windows	Sysmon · WinEventLog Security · CrowdStrike	Command and Control Ingress Tool Transfer Credential Access Steal or Forge Authentication Certificates	-	medium	Steven Dick	2023-07-28	2026-05-13	e6d2dc61-a8b9-4b03-906c-da0ca75d71b8
	Detects when a user enables DNS-over-HTTPS. (...)	Generic	test	registry_set	windows	Sysmon · WinEventLog Security	Stealth Deobfuscate/Decode Files or Information Persistence, Defense Impairment Modify Registry	-	medium	Austin Songer	2021-07-22	2023-08-17	04b45a8a-d11d-49e4-9acc-4a1b524407a5
	Detects the use of wget to download content to a suspicious directory	Generic	test	process_creation	linux	Sysmon	Command and Control Ingress Tool Transfer	-	medium	Joseliyo Sanchez, @Joseliyo_Jstnk	2023-06-02	—	cf610c15-ed71-46e1-bdf8-2bd1a99de6c4
Splunk	The following analytic detects suspicious file downloads by the Telegram application on a Windows system. (...)	Generic	stable	create_stream_hash	windows	Sysmon	Command and Control Ingress Tool Transfer	-	medium	Teoderick Contreras, Splunk	2021-05-07	2026-05-13	58194e28-ae5e-11eb-8912-acde48001122
	Detects download of certain file types from hosts with dynamic DNS names (selected list)	Generic	test	proxy	-	-	Command and Control Dynamic Resolution Command and Control Ingress Tool Transfer	-	medium	Florian Roth (Nextron Systems)	2017-11-08	2023-05-18	195c1119-ef07-4909-bb12-e66f5e07bf3c

Title

Description

CASTLETAP S1224

CASTLETAP MITRE reference S1224

Standing S1224

Reach

Coverage

CASTLETAP detections S1224