malware
KEYPLUG is a modular backdoor written in C++, with Windows and Linux variants, that has been used by APT41 since at least June 2021.[1]
Enterprise ATT&CK only. Any Mobile or ICS rows on the same ATT&CK page are not carried.
KEYPLUG can use a hardcoded one-byte XOR encoded configuration file.2
KEYPLUG has the ability to communicate over HTTP and WebSocket Protocol (WSS) for C2.3
KEYPLUG has used Cloudflare CDN associated infrastructure to redirect C2 communications to malicious domains.4
KEYPLUG can use TCP and KCP (KERN Communications Protocol) over UDP for C2 communication.5
The KEYPLUG Windows variant has retrieved C2 addresses from encoded data in posts on tech community forums.6
KEYPLUG can obtain the current tick count of an infected computer.7
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.
38th percentile · 62% of 825 ATT&CK software entries have more Enterprise techniques.
21st percentile · 79% of 825 ATT&CK software entries have more tactics spanned.
61% of the population shares a single value across only 22 distinct values, so a percentile here would rank the tie, not the entity.
85% of the population shares a single value across only 8 distinct values, so a percentile here would rank the tie, not the entity.
4th percentile · 96% of 825 ATT&CK software entries have more detection rules per technique.
122 distinct rules cover the 8 techniques recorded for this malware. 89 Sigma · 33 Splunk.
| Select | Title | Description | Category | Status | Event | OS | Product | MITRE ATT&CK | CVEs | Severity | Author | Created | Updated | ID | Refs |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Detects suspicious user agent strings used in APT malware in proxy logs | Generic | test | proxy | - | - | - | 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 | - | - | - | high | Thomas Patzke | 2019-11-12 | 2023-05-18 | 5ba715b6-71b7-44fd-8245-f66893e81b3d | ||||
Detects DNS queries for the malicious C2 domain associated with the plain-crypto-js/Axios npm package supply chain compromise. (...) | Emerging | experimental | dns | - | - | - | 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 | - | high | Florian Roth (Nextron Systems) | 2020-01-29 | 2023-01-26 | e32d4572-9826-4738-b651-95fa63747e8a | ||||
Detects Bitsadmin connections to IP addresses instead of FQDN names | Generic | test | proxy | - | - | - | 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 | - | - | - | high | Florian Roth (Nextron Systems), Tim Shelton | 2019-03-07 | 2026-09-30 | 9eb68894-7476-4cd6-8752-23b51f5883a7 | ||||
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 | - | 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 | - | - | - | 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 | - | medium | frack113 | 2022-01-23 | 2025-07-18 | d4488827-73af-4f8d-9244-7b7662ef046e | ||||
Find information about network devices that is not stored in config files | Generic | test | authentication | - | Cisco AAA · Cisco | - | low | Austin Clark | 2019-08-12 | 2023-01-04 | 9705a6a1-6db6-4a16-a987-15b7151e299b | ||||
Splunk | This analytic detects creation of a Cisco IOS-XE tunnel interface with tunnel source, tunnel destination, and an IP address in the 10.10.12.0 network. (...) | Anomaly | stable | network_device | - | Cisco IOS · Cisco | - | medium | Nasreddine Bencherchali | 2026-05-19 | 2026-05-20 | 8654314d-8e4d-4971-9f35-b9d477bf668e | |||
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 | - | medium | Radka Viskova, Splunk | 2026-09-18 | 2026-09-22 | 6bc88a9d-f7de-4257-b526-acf15bc5a517 | |||
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 | - | medium | Nasreddine Bencherchali, Splunk | 2025-04-03 | 2026-09-22 | c43f7b49-2dab-4e76-892e-7f971c2f20f1 | |||
Splunk | The following analytic detects outbound connections to commonly abused file sharing and pastebin-style hosting domains. (...) | Anomaly | stable | firewall | - | Cisco Secure Firewall · Cisco | - | medium | Nasreddine Bencherchali, Splunk | 2025-04-03 | 2026-05-13 | f7e5e792-d907-46c1-a58e-4ff974dc462a | |||
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 | - | 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 | - | 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 | - | 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 | - | medium | Nasreddine Bencherchali, Splunk, Talos NTDR | 2025-04-16 | 2026-05-13 | 66f22f52-fbae-4be7-a263-561dacb63612 | |||
Splunk | The following analytic detects outbound connections initiated by command-line tools such as curl or wget. (...) | Anomaly | stable | firewall | - | Cisco Secure Firewall · Cisco | - | medium | Nasreddine Bencherchali, Splunk | 2025-04-03 | 2026-05-13 | 173a1cb9-1814-4128-a9dc-f29dade89957 | |||
Detects execution of the "cloudflared" tool with the tunnel "cleanup" flag in order to cleanup tunnel connections. | Generic | test | process_creation | windows | Sysmon · WinEventLog Security | - | medium | Nasreddine Bencherchali (Nextron Systems) | 2023-05-17 | 2023-12-21 | 7050bba1-1aed-454e-8f73-3f46f09ce56a | ||||
Detects execution of the "cloudflared" tool to connect back to a tunnel. (...) | Generic | test | process_creation | windows | Sysmon · WinEventLog Security | - | medium | Janantha Marasinghe, Nasreddine Bencherchali (Nextron Systems) | 2023-05-17 | 2023-12-20 | 9a019ffc-3580-4c9d-8d87-079f7e8d3fd4 | ||||
Detects DNS requests to Cloudflared tunnels domains. (...) | Generic | test | dns | windows | Sysmon | - | medium | Nasreddine Bencherchali (Nextron Systems) | 2023-12-20 | — | a1d9eec5-33b2-4177-8d24-27fe754d0812 | ||||
Detects an executable initiating a network connection to "LocaltoNet" tunneling sub-domains. (...) | Generic | test | network_connection | windows | Sysmon | - | high | Andreas Braathen (mnemonic.io) | 2024-06-17 | — | 3ab65069-d82a-4d44-a759-466661a082d1 | ||||
Detects an executable initiating a network connection to "LocaltoNet" tunneling sub-domains. (...) | Generic | test | network_connection | linux | Sysmon | - | high | Andreas Braathen (mnemonic.io) | 2024-06-17 | — | c4568f5d-131f-4e78-83d4-45b2da0ec4f1 | ||||
Detects an executable accessing an ngrok tunneling endpoint, which could be a sign of forbidden exfi (...) | Generic | test | network_connection | linux | Sysmon | - | high | Florian Roth (Nextron Systems) | 2022-11-03 | — | 19bf6fdb-7721-4f3d-867f-53467f6a5db6 | ||||
Detects an executable initiating a network connection to "ngrok" tunneling domains. (...) | Generic | test | network_connection | windows | Sysmon | - | high | Florian Roth (Nextron Systems) | 2022-11-03 | 2024-02-02 | 1d08ac94-400d-4469-a82f-daee9a908849 | ||||
Detects Turla ComRAT network communication. | Emerging | test | proxy | - | - | - | high | Florian Roth (Nextron Systems) | 2020-05-26 | 2024-02-26 | 7857f021-007f-4928-8b2c-7aedbe64bb82 | ||||
Detects setting proxy configuration | Generic | test | process_creation | linux | Sysmon | - | low | Ömer Günal | 2020-06-17 | 2022-10-05 | 72f4ab3f-787d-495d-a55d-68c2ff46cf4c | - | |||
Detects suspicious user agent strings used by crypto miners in proxy logs | Generic | test | proxy | - | - | - | high | Florian Roth (Nextron Systems) | 2019-10-21 | 2021-11-27 | fa935401-513b-467b-81f4-f9e77aa0dd78 | ||||
Detects execution of curl.exe with custom useragent options | Hunting | test | process_creation | windows | Sysmon · WinEventLog Security | - | medium | frack113 | 2022-01-23 | 2023-02-21 | 3286d37a-00fd-41c2-a624-a672dcd34e60 | ||||
Identifies use of various commands to query a systems time. (...) | Generic | test | process_creation | windows | Sysmon · WinEventLog Security | - | low | E.M. Anhaus (originally from Atomic Blue Detections, Endgame), oscd.community | 2019-10-24 | 2022-06-28 | b243b280-65fe-48df-ba07-6ddea7646427 | ||||
Detects DNS queries initiated by "QuickAssist.exe" to Microsoft Quick Assist primary endpoint that is used to establish a session. | Generic | experimental | dns | windows | Sysmon | - | low | Muhammad Faisal (@faisalusuf) | 2024-12-19 | — | 882e858a-3233-4ba8-855e-2f3d3575803d | ||||
Detects DNS query requests to Devtunnels domains. (...) | Generic | test | dns | windows | Sysmon | - | medium | citron_ninja | 2023-10-25 | 2023-11-20 | 1cb0c6ce-3d00-44fc-ab9c-6d6d577bf20b | ||||
Detects DNS query requests to Visual Studio Code tunnel domains. (...) | Generic | test | dns | windows | Sysmon | - | medium | citron_ninja | 2023-10-25 | 2023-11-20 | b3e6418f-7c7a-4fad-993a-93b65027a9f1 | ||||
Detects when a user enables DNS-over-HTTPS. (...) | Generic | test | registry_set | windows | Sysmon · WinEventLog Security | - | medium | Austin Songer | 2021-07-22 | 2023-08-17 | 04b45a8a-d11d-49e4-9acc-4a1b524407a5 | ||||
Detects suspicious user agent strings used by exploit / pentest frameworks like Metasploit in proxy (...) | Generic | test | proxy | - | - | - | high | Florian Roth (Nextron Systems) | 2017-07-08 | 2025-01-18 | fdd1bfb5-f60b-4a35-910e-f36ed3d0b32f | ||||
Detects Baby Shark C2 Framework default communication patterns | Generic | test | proxy | - | - | - | critical | Florian Roth (Nextron Systems) | 2021-06-09 | 2024-02-15 | 304810ed-8853-437f-9e36-c4975c3dfd7e | ||||
Detects cobalt strike malleable profiles patterns (URI, User-Agents, Methods). | Generic | test | proxy | - | - | - | high | Markus Neis, Florian Roth (Nextron Systems) | 2024-02-15 | — | f3f21ce1-cdef-4bfc-8328-ed2e826f5fac | ||||
Detects user agent and URI paths used by empire agents | Generic | test | proxy | - | - | - | high | Florian Roth (Nextron Systems) | 2020-07-13 | 2024-02-26 | b923f7d6-ac89-4a50-a71a-89fb846b4aa8 | ||||
Detects executable names or flags used by Htran or Htran-like tools (e.g. (...) | Generic | test | process_creation | windows | Sysmon · WinEventLog Security | - | high | Florian Roth (Nextron Systems) | 2022-12-27 | 2023-02-04 | f5e3b62f-e577-4e59-931e-0a15b2b94e1e | ||||
Splunk | This Splunk query analyzes web logs to identify and categorize user agents, detecting various types of c2 frameworks. (...) | Generic | stable | webserver | - | Suricata | - | medium | Ravent Tait, Splunk | 2026-01-06 | 2026-09-22 | 229dc225-6abe-4d28-89fd-edf874086162 | |||
Splunk | Detects when a request has more than one of the same header. (...) | Anomaly | stable | network_connection | - | Suricata | - | medium | Raven Tait, Splunk | 2025-10-21 | 2026-05-13 | 1606cc5b-fd5f-4865-9fe3-0ed1eaec2df6 | |||
Splunk | This Splunk query analyzes web logs to identify and categorize user agents, detecting various types of malware. (...) | Generic | stable | webserver | - | Suricata | - | medium | Raven Tait, Splunk | 2026-01-06 | 2026-09-22 | 8c4866e4-f488-4253-8537-7dc4f954c292 | |||
Splunk | HTTP request smuggling is a technique for interfering with the way a web site processes sequences of HTTP requests that are received from one or more users. (...) | Generic | stable | network_connection | - | Suricata | - | medium | Raven Tait, Splunk | 2025-10-21 | 2026-05-13 | 97d85f98-9d15-41a0-8682-7030454875e7 | |||
Splunk | The following analytic detects HTTP POST requests containing heavily encoded data in the post body, specifically looking for sequences of hex-encoded bytes or base64-encoded strings. (...) | Anomaly | stable | network_connection | - | Zeek | - | medium | Raven Tait, Splunk | 2026-10-12 | 2026-10-12 | 0590881d-7b81-48dd-9674-1f23f7db5d40 | |||
Splunk | This Splunk query analyzes web logs to identify and categorize user agents, detecting various types of unwanted applications. (...) | Anomaly | stable | webserver | - | Suricata | - | medium | Raven Tait, Splunk | 2026-01-06 | 2026-09-22 | 21af5447-734f-4549-956b-7a255cb2b032 | |||
Splunk | This detection identifies rapid-fire POST request attacks where an attacker sends more than 20 POST requests within a 5-second window, potentially attempting to exploit race conditions or overwhelm request handling. (...) | Anomaly | stable | network_connection | - | Nginx | - | medium | Raven Tait, Splunk | 2025-10-21 | 2026-05-13 | c8c987d6-3a1a-4555-9a52-eea0741b6113 | |||
Splunk | Detects attempts to exploit a request smuggling technique against IIS that leverages a Windows quirk where requests for reserved Windows device names such as "/con" trigger an early server response before the request body is received. (...) | Generic | stable | webserver | - | Suricata | - | medium | Raven Tait, Splunk | 2025-10-21 | 2026-05-13 | 1e45e6a8-110b-4886-b815-8d69cf35bf0a | |||
Detects a potentially suspicious empty user agent strings in proxy log. (...) | Generic | test | proxy | - | - | - | medium | Florian Roth (Nextron Systems) | 2017-07-08 | 2021-11-27 | 21e44d78-95e7-421b-a464-ffd8395659c4 | ||||
Splunk | This Splunk query analyzes web logs to identify and categorize user agents, detecting various types of Remote Monitoring and Mangement applications. (...) | Anomaly | stable | webserver | - | Suricata | - | medium | Raven Tait, Splunk | 2026-01-06 | 2026-09-22 | 61884b02-0dcf-44c5-9094-db33bac09fa6 |
19th percentile · 81% of 825 ATT&CK software entries have more atomic tests per technique.
54% of the population shares a single value across only 11 distinct values, so a percentile here would rank the tie, not the entity.
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 8 Enterprise techniques.
Technique Campaign use over its cumulative rule count.