malware

DOWNIISSA S9021

Type: malware
Platform: Windows
Created: 17 April 2026
Last modified: 24 April 2026

DOWNIISSA is a shellcode downloader that has been used by MirrorFace since at least 2022 to deploy payloads, including the LODEINFO backdoor.[1]

Techniques33rd pct

Tactics32nd pct

Threat groupunranked

CampaignsNone recorded

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

Standing S9021

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 the deletion of the "Zone.Identifier" ADS. (...)	Hunting	test	file_delete	windows	Sysmon	Stealth Indicator Removal File Deletion	-	low	frack113	2023-09-04	—	7eac0a16-5832-4e81-865f-0268a6d19e4b
	Detects the deletion of the "Zone.Identifier" ADS by an uncommon process. (...)	Generic	test	file_delete	windows	Sysmon	Stealth Indicator Removal File Deletion	-	medium	Nasreddine Bencherchali (Nextron Systems)	2023-09-04	2025-07-04	3109530e-ab47-4cc6-a953-cac5ebcc93ae
	Detects the suspicious file that is created from PoC code against Windows Print Spooler Remote Code Execution Vulnerability CVE-2021-34527 (PrinterNightmare), CVE-2021-1675 .	Emerging	stable	antivirus	-	-	Privilege Escalation, Stealth Process Injection	CVE-2021-1675 CVE-2021-34527	critical	Sittikorn S, Nuttakorn T, Tim Shelton	2021-07-01	2023-10-23	6fe1719e-ecdf-4caf-bffe-4f501cb0a561
	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 an image load pattern as seen when a tool named PRIVATELOG is used and rarely observed under (...)	Emerging	test	image_load	windows	Sysmon	Privilege Escalation, Stealth Process Injection	-	high	Florian Roth (Nextron Systems)	2021-09-07	2022-10-09	33a2d1dd-f3b0-40bd-8baf-7974468927cc
	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	Detects identities generating anomalously large model responses relative to their own historical baseline. (...)	Anomaly	stable	-	-	AWS	Privilege Escalation, Stealth Process Injection	-	medium	Rod Soto	2026-07-06	2026-07-06	a839a6f7-aaac-438b-9d99-be0b49481e17
Splunk	Detects identities invoking high-risk filesystem and execution tools via AWS Bedrock Claude. (...)	Anomaly	stable	-	-	AWS	Privilege Escalation, Stealth Process Injection	-	medium	Rod Soto	2026-07-06	2026-07-06	989b3702-1df3-4076-9e2f-8dcbcc2b4bef
Splunk	This detection identifies prompts with hostile or aggressive sentiment being sent to AWS Bedrock Claude models. (...)	Anomaly	stable	-	-	AWS	Privilege Escalation, Stealth Process Injection	-	medium	Rod Soto	2026-07-06	2026-07-06	54734442-955a-4427-9a86-2d9712151067
Splunk	This search surfaces AWS Bedrock Claude prompts containing phrases commonly associated with prompt injection or jailbreak attempts, such as instruction overrides, persona switching, or requests to ignore prior guidance. (...)	Hunting	stable	-	-	AWS	Privilege Escalation, Stealth Process Injection	-	medium	Rod Soto	2026-07-06	2026-07-06	9e162548-3e9a-4a74-9eb5-34ee28350f07
Splunk	This detection identifies sensitive data such as social security numbers, passwords, API keys, and credit card numbers being sent in prompts to AWS Bedrock Claude models. (...)	Anomaly	stable	-	-	AWS	Privilege Escalation, Stealth Process Injection	-	medium	Rod Soto	2026-07-06	2026-07-06	39346724-a73a-4e01-8e93-4f4791e1a0bb
Splunk	This detection identifies unusually large prompts sent to AWS Bedrock Claude models by calculating the statistical baseline of input token counts and flagging requests that exceed one standard deviations above the mean. (...)	Anomaly	stable	-	-	AWS	Privilege Escalation, Stealth Process Injection	-	medium	Rod Soto	2026-07-06	2026-07-08	95fbdd4e-1202-4971-b85a-513b2005086e
	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 backup catalog deletions	Generic	test	-	windows	WinEventLog Application	Stealth Indicator Removal File Deletion	-	medium	Florian Roth (Nextron Systems), Tom U. @c_APT_ure (collection)	2017-05-12	2022-12-25	9703792d-fd9a-456d-a672-ff92efe4806a
	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 BPFDoor .lock and .pid files access in temporary file storage facility	Generic	test	file_event	linux	Linux Auditd	Execution Command and Scripting Interpreter Execution Native API	-	high	Rafal Piasecki	2022-08-10	2026-03-30	808146b2-9332-4d78-9416-d7e47012d83d
	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
	See what files are being deleted from flash file systems	Generic	test	authentication	-	Cisco AAA · Cisco	Impact Disk Wipe Disk Content Wipe Disk Structure Wipe Stealth Indicator Removal File Deletion	-	medium	Austin Clark	2019-08-12	2023-01-04	71d65515-c436-43c0-841b-236b1f32c21e	-
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 network connections initiated by binaries that are not typically associated wi (...)	Anomaly	stable	network_connection	-	Cisco NVM · Cisco	Stealth Masquerading Privilege Escalation, Stealth Process Injection	-	medium	Nasreddine Bencherchali, Splunk	2025-07-01	2026-09-22	c6db35af-8a0e-4b61-88ed-738e66f15715
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 system binaries that are commonly abused in process injection techniques but are observed without any command-line arguments. (...)	Anomaly	stable	network_connection	-	Cisco NVM · Cisco	Privilege Escalation, Stealth Process Injection Stealth System Binary Proxy Execution	-	medium	Nasreddine Bencherchali, Splunk	2025-07-01	2026-09-22	54fa06c5-96a2-4406-a4a7-44d93ddbd173
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 execution of `cipher.exe` with the `/w` flag to clear unallocated sectors on a disk. (...)	Generic	stable	process_creation	windows	Sysmon · WinEventLog Security · CrowdStrike	Stealth Indicator Removal File Deletion	-	medium	Teoderick Contreras, Splunk	2021-06-10	2026-05-13	cd80a6ac-c9d9-11eb-8839-acde48001122
	Detects the creation of a named pipe as used by CobaltStrike	Generic	test	pipe_created	windows	Sysmon	Privilege Escalation, Stealth Process Injection	-	critical	Florian Roth (Nextron Systems), Wojciech Lesicki	2021-05-25	2022-10-31	d5601f8c-b26f-4ab0-9035-69e11a8d4ad2
	Detects the creation of a named pipe matching a pattern used by CobaltStrike Malleable C2 profiles	Generic	test	pipe_created	windows	Sysmon	Privilege Escalation, Stealth Process Injection	-	critical	Florian Roth (Nextron Systems)	2021-07-30	2026-06-18	0e7163d4-9e19-4fa7-9be6-000c61aad77a
	Detects the creation of a named pipe with a pattern found in CobaltStrike malleable C2 profiles	Generic	test	pipe_created	windows	Sysmon	Privilege Escalation, Stealth Process Injection	-	high	Florian Roth (Nextron Systems), Christian Burkard (Nextron Systems)	2021-07-30	2024-01-26	85adeb13-4fc9-4e68-8a4a-c7cb2c336eb7
	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
Splunk	The following analytic detects suspicious process injection in command shell applications, specifically targeting `cmd.exe` and `powershell.exe`. (...)	Generic	stable	create_remote_thread	windows	Sysmon	Privilege Escalation, Stealth Process Injection	-	medium	Teoderick Contreras, Splunk	2021-08-05	2026-06-29	10399c1e-f51e-11eb-b920-acde48001122
	This rule detects suspicious files created by Microsoft Sync Center (mobsync)	Generic	test	file_event	windows	Sysmon	Privilege Escalation, Stealth Process Injection Stealth System Binary Proxy Execution	-	medium	elhoim	2022-04-28	2022-06-02	409f8a98-4496-4aaa-818a-c931c0a8b832
	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

Title

Description

DOWNIISSA S9021

DOWNIISSA MITRE reference S9021

Standing S9021

Reach

Coverage

DOWNIISSA detections S9021