- S0017 BISCUIT — malware.
BISCUIT malware contains a secondary fallback command and control server that is contacted after the primary command and control server.[Mandiant APT1][Mandiant APT1 Appendix]
Exact relationship: relationship--3ac3a282-e1be-45f8-8974-0a94e5d43644 - S0021 Derusbi — malware.
Derusbi uses a backup communication method with an HTTP beacon.[Fidelis Turbo]
Exact relationship: relationship--bd74b90d-ff9f-4ce3-96af-9b809fffc3da - S0022 Uroburos — malware.
Uroburos can use up to 10 channels to communicate between implants.[Joint Cybersecurity Advisory AA23-129A Snake Malware May 2023]
Exact relationship: relationship--a7005b59-48e5-4852-90f7-ed8d2c3698fa - S0023 CHOPSTICK — malware.
CHOPSTICK can switch to a new C2 channel if the current one is broken.[ESET Sednit Part 2]
Exact relationship: relationship--101867a2-149c-4088-a90f-7af4b86e5013 - S0034 NETEAGLE — malware.
NETEAGLE will attempt to detect if the infected host is configured to a proxy. If so, NETEAGLE will send beacons via an HTTP POST request; otherwise it will send beacons via UDP/6000.[FireEye APT30]
Exact relationship: relationship--a713d0d3-2897-4da2-995f-df3a40f04b29 - S0044 JHUHUGIT — malware.
JHUHUGIT tests if it can reach its C2 server by first attempting a direct connection, and if it fails, obtaining proxy settings and sending the connection through a proxy, and finally injecting code into a running browser if the proxy method fails.[ESET Sednit Part 1]
Exact relationship: relationship--0d43f3a7-70ed-4d04-857e-3a9fbce86cfb - S0051 MiniDuke — malware.
MiniDuke uses Google Search to identify C2 servers if its primary C2 method via Twitter is not working.[Securelist MiniDuke Feb 2013]
Exact relationship: relationship--62c8913c-c193-4feb-ab58-88343838336d - S0058 SslMM — malware.
SslMM has a hard-coded primary and backup C2 string.[Baumgartner Naikon 2015]
Exact relationship: relationship--329678a6-eb6b-499b-90a8-059d1cf1a35f - S0059 WinMM — malware.
WinMM is usually configured with primary and backup domains for C2 communications.[Baumgartner Naikon 2015]
Exact relationship: relationship--70a93fc8-83c0-4407-8224-ae447af1235a - S0062 DustySky — malware.
DustySky has two hard-coded domains for C2 servers; if the first does not respond, it will try the second.[DustySky]
Exact relationship: relationship--b2ab26e2-eb90-4f19-b35a-b8a0a5438961 - S0084 Mis-Type — malware.
Mis-Type first attempts to use a Base64-encoded network protocol over a raw TCP socket for C2, and if that method fails, falls back to a secondary HTTP-based protocol to communicate to an alternate C2 server.[Cylance Dust Storm]
Exact relationship: relationship--a61cf8cf-87f1-4061-ae9d-31e8162bdfef - S0085 S-Type — malware.
S-Type primarily uses port 80 for C2, but falls back to ports 443 or 8080 if initial communication fails.[Cylance Dust Storm]
Exact relationship: relationship--4b23ac99-3761-46f0-ad5d-2cf63a95036a - S0089 BlackEnergy — malware.
BlackEnergy has the capability to communicate over a backup channel via plus.google.com.[Securelist BlackEnergy Nov 2014]
Exact relationship: relationship--f5936bbd-f8cb-404a-bd43-87f7bc836294 - S0117 XTunnel — malware.
The C2 server used by XTunnel provides a port number to the victim to use as a fallback in case the connection closes on the currently used port.[ESET Sednit Part 2]
Exact relationship: relationship--e97b39d6-7be1-4f59-8959-7f1f01402152 - S0211 Linfo — malware.
Linfo creates a backdoor through which remote attackers can change C2 servers.[Symantec Linfo May 2012]
Exact relationship: relationship--0fbd4496-f715-4edd-b4da-169d6047a7c9 - S0236 Kwampirs — malware.
Kwampirs uses a large list of C2 servers that it cycles through until a successful connection is established.[Symantec Orangeworm April 2018]
Exact relationship: relationship--e2317e9b-9301-4c44-959f-94d66858136c - S0260 InvisiMole — malware.
InvisiMole has been configured with several servers available for alternate C2 communications.[ESET InvisiMole June 2018][ESET InvisiMole June 2020]
Exact relationship: relationship--1f728f8c-8aee-4d40-9161-1cae773983d1 - S0265 Kazuar — malware.
Kazuar can accept multiple URLs for C2 servers.[Unit 42 Kazuar May 2017]
Exact relationship: relationship--950399e7-c9c2-4b53-bcc8-b99d0acba8d1 - S0266 TrickBot — malware.
TrickBot can use secondary C2 servers for communication after establishing connectivity and relaying victim information to primary C2 servers.[Cyberreason Anchor December 2019]
Exact relationship: relationship--3fa8155d-11ca-47de-902e-47e809d0ed64 - S0269 QUADAGENT — malware.
QUADAGENT uses multiple protocols (HTTPS, HTTP, DNS) for its C2 server as fallback channels if communication with one is unsuccessful.[Unit 42 QUADAGENT July 2018]
Exact relationship: relationship--dc4bc74b-cd60-4853-a436-8d5e34b01564 - S0348 Cardinal RAT — malware.
Cardinal RAT can communicate over multiple C2 host and port combinations.[PaloAlto CardinalRat Apr 2017]
Exact relationship: relationship--d3e0b0b8-797f-4638-bcb6-aa688c3a0a9a - S0376 HOPLIGHT — malware.
HOPLIGHT has multiple C2 channels in place in case one fails.[US-CERT HOPLIGHT Apr 2019]
Exact relationship: relationship--1708aa35-a362-429f-be06-82dc106dfeb4 - S0377 Ebury — malware.
Ebury has implemented a fallback mechanism to begin using a DGA when the attacker hasn't connected to the infected system for three days.[ESET Ebury Oct 2017]
Exact relationship: relationship--36849ab3-088c-47a5-bcf9-3e68902a2e60 - S0401 Exaramel for Linux — malware.
Exaramel for Linux can attempt to find a new C2 server if it receives an error.[ANSSI Sandworm January 2021]
Exact relationship: relationship--73a5da20-5358-4da8-8417-020a7dec52cb - S0409 Machete — malware.
Machete has sent data over HTTP if FTP failed, and has also used a fallback server.[ESET Machete July 2019]
Exact relationship: relationship--bdb7f4c5-3620-479b-af38-95f42e82fb68 - S0444 ShimRat — malware.
ShimRat has used a secondary C2 location if the first was unavailable.[FOX-IT May 2016 Mofang]
Exact relationship: relationship--a2118212-1594-4fb1-8076-5a8649756c9c - S0476 Valak — malware.
Valak can communicate over multiple C2 hosts.[Unit 42 Valak July 2020]
Exact relationship: relationship--495982e4-9856-4e7f-8e05-4654d67a4d62 - S0495 RDAT — malware.
RDAT has used HTTP if DNS C2 communications were not functioning.[Unit42 RDAT July 2020]
Exact relationship: relationship--d96db78c-e7b8-4877-8187-07c5e801cead - S0501 PipeMon — malware.
PipeMon can switch to an alternate C2 domain when a particular date has been reached.[ESET PipeMon May 2020]
Exact relationship: relationship--ecca736a-9b3f-4a1d-bdb8-ff5c55197893 - S0504 Anchor — malware.
Anchor can use secondary C2 servers for communication after establishing connectivity and relaying victim information to primary C2 servers.[Cyberreason Anchor December 2019]
Exact relationship: relationship--f9fc4a7b-e8ba-4e50-b97f-9afabcfc73a8 - S0512 FatDuke — malware.
FatDuke has used several C2 servers per targeted organization.[ESET Dukes October 2019]
Exact relationship: relationship--4e2842c6-ce4c-4204-9f29-4442a1859f12 - S0534 Bazar — malware.
Bazar has the ability to use an alternative C2 server if the primary server fails.[NCC Group Team9 June 2020]
Exact relationship: relationship--c1d43be1-daea-4cdd-9632-e0a22f4d9073 - S0538 Crutch — malware.
Crutch has used a hardcoded GitHub repository as a fallback channel.[ESET Crutch December 2020]
Exact relationship: relationship--d207f54d-81c1-4b20-ba56-575fbdec2f03 - S0586 TAINTEDSCRIBE — malware.
TAINTEDSCRIBE can randomly pick one of five hard-coded IP addresses for C2 communication; if one of the IP fails, it will wait 60 seconds and then try another IP address.[CISA MAR-10288834-2.v1 TAINTEDSCRIBE MAY 2020]
Exact relationship: relationship--d2d98eeb-4ebd-4db5-adf8-2a737306b17f - S0603 Stuxnet — malware.
Stuxnet has the ability to generate new C2 domains.[Nicolas Falliere, Liam O Murchu, Eric Chien February 2011]
Exact relationship: relationship--85b5e45d-247e-4c8b-a991-95700e4d81d9 - S0610 SideTwist — malware.
SideTwist has primarily used port 443 for C2 but can use port 80 as a fallback.[Check Point APT34 April 2021]
Exact relationship: relationship--abdaccd2-6a3e-4bd2-8fa2-b192f67f22ca - S0622 AppleSeed — malware.
AppleSeed can use a second channel for C2 when the primary channel is in upload mode.[Malwarebytes Kimsuky June 2021]
Exact relationship: relationship--98fc2f95-0c93-405a-a54e-880622d8d233 - S0629 RainyDay — malware.
RainyDay has the ability to switch between TCP and HTTP for C2 if one method is not working.[Bitdefender Naikon April 2021]
Exact relationship: relationship--8492aff7-1171-4805-9052-3decdd677c94 - S0666 Gelsemium — malware.
Gelsemium can use multiple domains and protocols in C2.[ESET Gelsemium June 2021]
Exact relationship: relationship--a01e5280-ae4f-4edd-bb57-e29e8426cc3b - S0668 TinyTurla — malware.
TinyTurla can go through a list of C2 server IPs and will try to register with each until one responds.[Talos TinyTurla September 2021]
Exact relationship: relationship--b4642810-53c4-4ff2-859f-f4b707a36097 - S0674 CharmPower — malware.
CharmPower can change its C2 channel once every 360 loops by retrieving a new domain from the actors’ S3 bucket.[Check Point APT35 CharmPower January 2022]
Exact relationship: relationship--94a1fe68-4c8f-48ca-b186-feca5f800f46 - S0699 Mythic — tool.
Mythic can use a list of C2 URLs as fallback mechanisms in case one IP or domain gets blocked.[Mythc Documentation]
Exact relationship: relationship--f1ab6a18-2624-4d35-b9e2-3f3a4288bcac - S1019 Shark — malware.
Shark can update its configuration to use a different C2 server.[ClearSky Siamesekitten August 2021]
Exact relationship: relationship--61952f05-92a3-41e0-93c4-d7486a927ece - S1020 Kevin — malware.
Kevin can assign hard-coded fallback domains for C2.[Kaspersky Lyceum October 2021]
Exact relationship: relationship--b921077b-4a62-461c-aaec-9cd70b5cf5f8 - S1039 Bumblebee — malware.
Bumblebee can use backup C2 servers if the primary server fails.[Proofpoint Bumblebee April 2022]
Exact relationship: relationship--7327153c-c123-401b-b675-554b8070fbed - S1084 QUIETEXIT — malware.
QUIETEXIT can attempt to connect to a second hard-coded C2 if the first hard-coded C2 address fails.[Mandiant APT29 Eye Spy Email Nov 22]
Exact relationship: relationship--550d2a38-7dd8-497d-b65d-43b65a3ec49e - S1172 OilBooster — malware.
OilBooster can use a backup channel to request a new refresh token from its C2 server after 10 consecutive unsuccessful connections to the primary OneDrive C2 server.[ESET OilRig Downloaders DEC 2023]
Exact relationship: relationship--e425fe3b-b6a3-4a90-b11c-8b2fbc122f72 - S9010 GlassWorm — malware.
GlassWorm has utilized Google Calendar as backup C2.[Koi Glassworm InvisibleCode October 2025][Koi GlassWorm Rust December 2025]
Exact relationship: relationship--af0ba134-74c9-4256-a48d-6911e98cf235 - S9023 HiddenFace — malware.
HiddenFace can use active and passive C2 modes that use different encryption algorithms and backdoor commands.[Trend Micro Earth Kasha NOV 2024]
Exact relationship: relationship--52ce2f48-1bb7-48f9-8ac6-56002d93672f - S9041 TeamPCP Cloud Stealer — malware.
TeamPCP Cloud Stealer can compress and encrypt data and exfiltrate it via POST to an attacker-controlled domain. If that method fails it can use the victim's own GitHub account to create a public repository and uploads the encrypted data as a release asset.[Wiz Trivy Compromise MAR 2026][Aqua Security Trivy Compromise MAR 2026][Aqua Security Blog Trivy Compromise APR 2026][Wiz TeamPCP KICS MAR 2026][Palo Alto TeamPCP MAR 2026]
Exact relationship: relationship--60636234-2547-4139-8f91-e0b984ec5d06 - S9043 Mini Shai-Hulud — malware.
Mini Shai-Hulud has established Fallback Channels to exfiltrate data to Github when other configured infrastructure is found to be unreachable.[Wiz Mini Shai-Hulud MAY 2026][Trend Micro TeamPCP MAY 2026][Hunt.io TeamPCP Toolkit MAY 2026][Phoenix TeamPCP 20 MAY 2026]
Exact relationship: relationship--bc21fc79-4a67-46e8-b514-efb20e92b3f7 - S9063 DEEPROOT — malware.
DEEPROOT has communicated with multiple C2 servers as a means of redundancy if one fails.[Mandiant_UNC1549_Nov2025]
Exact relationship: relationship--0a04902b-be91-45d9-94de-3ccc3b7c6cbd