YAHOYAH S0388

Type: malware
Platform: Windows
Created: 17 June 2019
Last modified: 19 April 2024

YAHOYAH is a Trojan used by Tropic Trooper as a second-stage backdoor.[1]

Techniques29th pct

TacticsBottom 21%

Threat groupunranked

CampaignsNone recorded

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

YAHOYAH MITRE reference S0388

Encrypted/Encoded File T1027.013 ↗

YAHOYAH encrypts its configuration file using a simple algorithm.2

Stealth1 detection rules

Web Protocols T1071.001 ↗

YAHOYAH uses HTTP for C2.3

Command and Control60 detection rules

System Information Discovery T1082 ↗

YAHOYAH checks for the system’s Windows OS version and hostname.4

Discovery54 detection rules

Ingress Tool Transfer T1105 ↗

YAHOYAH uses HTTP GET requests to download other files that are executed in memory.5

Command and Control131 detection rules

Deobfuscate/Decode Files or Information T1140 ↗

YAHOYAH decrypts downloaded files before execution.6

Stealth20 detection rules

Security Software Discovery T1518.001 ↗

YAHOYAH checks for antimalware solution processes on the system.7

Discovery9 detection rules

Standing S0388

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

Techniques629th pct

29th percentile · 71% of 825 ATT&CK software entries have more Enterprise techniques.

Tactics3Bottom 21%

21st percentile · 79% 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 / technique37medTop 16%

84th percentile · 84% of 825 ATT&CK software entries have this many detection rules per technique or fewer.

Tests / technique11.5med

YAHOYAH detections S0388

272 distinct rules cover the 6 techniques recorded for this malware. 192 Sigma · 80 Splunk.

6 covered by at least one rule272 distinct rules in total

Showing 1-50 of 200+ rules

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Select	Description	Category	Status	Event	OS	Product	MITRE ATT&CK	CVEs	Severity	Author	Created	Updated	ID	Refs
	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 suspicious user agent strings used in APT malware in proxy logs	Generic	test	proxy	-	-	Command and Control Application Layer Protocol Web Protocols	-	high	Florian Roth (Nextron Systems), Markus Neis	2019-11-12	2024-02-15	6ec820f2-e963-4801-9127-d8b2dce4d31b
	Detects suspicious user agent string of APT40 Dropbox tool	Emerging	test	proxy	-	-	Command and Control Application Layer Protocol Web Protocols Exfiltration Exfiltration Over Web Service Exfiltration to Cloud Storage	-	high	Thomas Patzke	2019-11-12	2023-05-18	5ba715b6-71b7-44fd-8245-f66893e81b3d
	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 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 DNS queries for the malicious C2 domain associated with the plain-crypto-js/Axios npm package supply chain compromise. (...)	Emerging	experimental	dns	-	-	Command and Control Application Layer Protocol Web Protocols Command and Control Dynamic Resolution	-	high	Swachchhanda Shrawan Poudel (Nextron Systems)	2026-04-01	—	73e5d24f-493f-4092-bd2f-c72cabda40ee
	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
	Detects user data export activity.	Generic	test	cloud_audit	-	Bitbucket Audit · Bitbucket	Collection Data from Information Repositories Reconnaissance Gather Victim Org Information Identify Roles Discovery System Information Discovery	-	medium	Muhammad Faisal (@faisalusuf)	2024-02-25	—	5259cbf2-0a75-48bf-b57a-c54d6fabaef3
	Detects user permission data export attempt.	Generic	test	cloud_audit	-	Bitbucket Audit · Bitbucket	Collection Data from Information Repositories Reconnaissance Gather Victim Org Information Identify Roles Discovery System Information Discovery	-	medium	Muhammad Faisal (@faisalusuf)	2024-02-25	—	87cc6698-3e07-4ba2-9b43-a85a73e151e2
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 Bitsadmin connections to IP addresses instead of FQDN names	Generic	test	proxy	-	-	Command and Control Application Layer Protocol Web Protocols Execution, Persistence, Stealth BITS Jobs	-	high	Florian Roth (Nextron Systems)	2022-06-10	2022-08-24	8ccd35a2-1c7c-468b-b568-ac6cdf80eec3
	Detects Bitsadmin connections to domains with uncommon TLDs	Generic	test	proxy	-	-	Command and Control Application Layer Protocol Web Protocols Execution, Persistence, Stealth BITS Jobs	-	high	Florian Roth (Nextron Systems), Tim Shelton	2019-03-07	2026-09-30	9eb68894-7476-4cd6-8752-23b51f5883a7
	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
	Detects HTTP request used by Chafer malware to receive data from its C2.	Emerging	test	proxy	-	-	Command and Control Application Layer Protocol Web Protocols	-	high	Florian Roth (Nextron Systems)	2019-01-31	2024-02-15	fb502828-2db0-438e-93e6-801c7548686d
	Adversaries may communicate using application layer protocols associated with web traffic to avoid detection/network filtering by blending in with existing traffic. (...)	Generic	test	ps_script	windows	PowerShell	Command and Control Application Layer Protocol Web Protocols	-	medium	frack113	2022-01-23	2025-07-18	d4488827-73af-4f8d-9244-7b7662ef046e
Splunk	This analytic detects potential reconnaissance activities on Cisco ASA devices by identifying execution of multiple information-gathering "show" commands within a short timeframe. (...)	Anomaly	stable	firewall	-	Cisco Secure Firewall · Cisco	Reconnaissance Gather Victim Network Information Domain Properties IP Addresses Discovery System Information Discovery	-	medium	Nasreddine Bencherchali, Splunk	2025-11-21	2026-05-13	6e9d4f7a-3c8b-4a9e-8d2f-7b5c9e1a6f3d
	Find information about network devices that is not stored in config files	Generic	test	authentication	-	Cisco AAA · Cisco	Discovery File and Directory Discovery Discovery Password Policy Discovery Discovery Process Discovery Discovery Remote System Discovery Discovery System Information Discovery Discovery System Network Configuration Discovery Discovery System Network Connections Discovery Discovery System Owner/User Discovery Discovery System Time Discovery	-	low	Austin Clark	2019-08-12	2023-01-04	9705a6a1-6db6-4a16-a987-15b7151e299b
Splunk	This analytic detects bursts of Cisco IOS or NX-OS discovery commands associated with Salt Typhoon tradecraft. (...)	Anomaly	stable	network_device	-	Cisco IOS · Cisco	Reconnaissance Gather Victim Network Information Discovery System Information Discovery Discovery System Network Configuration Discovery	-	medium	Nasreddine Bencherchali	2026-05-19	2026-05-20	71ac5328-2364-40cf-8381-92b8dc531399
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 detects the usage of the Utility osascript on a macOS device initiated a network connection lasting longer than 10 minutes (600 seconds). (...)	Anomaly	stable	network_connection	-	Cisco NVM · Cisco	Command and Control Application Layer Protocol Web Protocols Execution Command and Scripting Interpreter AppleScript	-	medium	Radka Viskova, Splunk	2026-09-18	2026-09-22	6bc88a9d-f7de-4257-b526-acf15bc5a517
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	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
	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	-
	Detects DNS requests to Cloudflared tunnels domains. (...)	Generic	test	dns	windows	Sysmon	Command and Control Application Layer Protocol Web Protocols Command and Control Protocol Tunneling	-	medium	Nasreddine Bencherchali (Nextron Systems)	2023-12-20	—	a1d9eec5-33b2-4177-8d24-27fe754d0812
	Detects the use of the redirection character ">" to redirect information on the command line. (...)	Hunting	test	process_creation	windows	Sysmon · WinEventLog Security	Discovery System Information Discovery	-	low	frack113	2022-01-22	2024-03-19	4f4eaa9f-5ad4-410c-a4be-bc6132b0175a
	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 Turla ComRAT network communication.	Emerging	test	proxy	-	-	Command and Control Application Layer Protocol Web Protocols	-	high	Florian Roth (Nextron Systems)	2020-05-26	2024-02-26	7857f021-007f-4928-8b2c-7aedbe64bb82
	Detects potential container discovery via listing of certain kernel features in the "/proc" virtual (...)	Generic	test	process_creation	linux	Sysmon	Discovery System Information Discovery	-	low	Seth Hanford	2023-08-23	—	746c86fb-ccda-4816-8997-01386263acc4
	Detects suspicious user agent strings used by crypto miners in proxy logs	Generic	test	proxy	-	-	Command and Control Application Layer Protocol Web Protocols	-	high	Florian Roth (Nextron Systems)	2019-10-21	2021-11-27	fa935401-513b-467b-81f4-f9e77aa0dd78
	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 execution of curl.exe with custom useragent options	Hunting	test	process_creation	windows	Sysmon · WinEventLog Security	Command and Control Application Layer Protocol Web Protocols	-	medium	frack113	2022-01-23	2023-02-21	3286d37a-00fd-41c2-a624-a672dcd34e60
	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 identifies specific GET or HEAD requests to web servers that indicate reconnaissance attempts to find vulnerable JBoss servers. (...)	Generic	experimental	webserver	-	-	Initial Access, Persistence External Remote Services Discovery System Information Discovery	-	medium	Bhavin Patel, Splunk	2020-04-29	2026-05-13	104658f4-afdc-499e-9719-17243f982681	-