malware

Seth-Locker S0639

Type: malware
Platform: Windows
Created: 13 August 2021
Last modified: 25 April 2025

Seth-Locker is a ransomware with some remote control capabilities that has been in use since at least 2021. [1]

TechniquesBottom 12%

TacticsBottom 21%

Threat groupsNone recorded

CampaignsNone recorded

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

Seth-Locker MITRE reference S0639

Windows Command Shell T1059.003 ↗

Seth-Locker can execute commands via the command line shell.2

Execution63 detection rules

Ingress Tool Transfer T1105 ↗

Seth-Locker has the ability to download and execute files on a compromised host.3

Command and Control131 detection rules

Data Encrypted for Impact T1486 ↗

Seth-Locker can encrypt files on a targeted system, appending them with the suffix .seth.4

Impact27 detection rules

Standing S0639

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

Techniques3Bottom 12%

12th percentile · 88% 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 groups061% 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 / technique63medTop 3%

97th percentile · 97% of 825 ATT&CK software entries have this many detection rules per technique or fewer.

Tests / technique10medTop 9%

91st percentile · 91% of 825 ATT&CK software entries have this many atomic tests per technique or fewer.

Data comps / technique5med54% 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 / technique2medTop 9%

91st percentile · 91% 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 3 Enterprise techniques.

Range

Technique Campaign use over its cumulative rule count.

Campaigns · 0Sigma rules (cumulative) · 147Splunk ESCU (cumulative) · 71

Standing S0639

Select	Description	Category	Status	Event	OS	Product	MITRE ATT&CK	CVEs	Severity	Author	Created	Updated	ID	Refs
	Detects a highly relevant Antivirus alert that reports ransomware. (...)	Generic	test	antivirus	-	-	Impact Data Encrypted for Impact	-	critical	Florian Roth (Nextron Systems), Arnim Rupp	2022-05-12	2026-06-15	4c6ca276-d4d0-4a8c-9e4c-d69832f8671f
	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 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
Splunk	The following analytic detects the creation of AWS KMS keys with an encryption policy accessible to everyone, including external entities. (...)	Generic	stable	cloud_audit	-	AWS CloudTrail · AWS	Impact Data Encrypted for Impact	-	medium	Patrick Bareiss, Splunk	2020-10-27	2026-05-13	16ae9076-d1d5-411c-8fdd-457504b33dac
Splunk	The following analytic detects the creation of AWS KMS keys with an encryption policy accessible to everyone, including external entities. (...)	Generic	stable	cloud_audit	-	AWS CloudTrail · AWS	Impact Data Encrypted for Impact	-	medium	Rod Soto, Patrick Bareiss Splunk	2020-10-27	2026-05-13	c79c164f-4b21-4847-98f9-cf6a9f49179e
Splunk	The following analytic identifies users with KMS keys performing encryption operations on S3 buckets. (...)	Anomaly	stable	cloud_audit	-	AWS CloudTrail · AWS	Impact Data Encrypted for Impact	-	medium	Rod Soto, Patrick Bareiss Splunk	2020-10-27	2026-05-13	884a5f59-eec7-4f4a-948b-dbde18225fdc
	Identifies disabling of default Amazon Elastic Block Store (EBS) encryption in the current region. (...)	Generic	stable	cloud_audit	-	AWS CloudTrail · AWS	Impact Data Encrypted for Impact Impact Data Manipulation	-	medium	Sittikorn S	2021-06-29	2021-08-20	16124c2d-e40b-4fcc-8f2c-5ab7870a2223
	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 import or deletion of key material in AWS KMS, which can be used as part of ransomware attacks. (...)	Generic	experimental	cloud_audit	-	AWS CloudTrail · AWS	Impact Data Encrypted for Impact Resource Development Stage Capabilities Install Digital Certificate	-	high	toopricey	2025-10-18	—	1279262f-1464-422f-ac0d-5b545320c526
	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
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
	Detect access to files and shares with names and extensions used by BlueSky ransomware which could indicate a current or previous encryption attempt.	Emerging	test	file_event	windows	WinEventLog Security	Impact Data Encrypted for Impact	-	high	j4son	2023-05-23	—	eee8311f-a752-44f0-bf2f-6b007db16300
	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 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 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	-
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
	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
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 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
	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 executable access via webdav6. (...)	Generic	test	-	-	HTTP · Zeek	Command and Control Ingress Tool Transfer	-	medium	SOC Prime, Adam Swan	2020-05-01	2021-11-27	aac2fd97-bcba-491b-ad66-a6edf89c71bf

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