T1090.003: Multi-hop Proxy

Ember Bear is a Russian state-sponsored cyber espionage group that has been active since at least 2020, linked to Russia's General Staff Main Intelligence Directorate (GRU) 161st Specialist Training Center (Unit 29155).[1] Ember Bear has primarily focused operations against Ukrainian government and telecommunication entities, but has also operated against critical infrastructure entities in Europe and the Americas.[2] Ember Bear conducted the WhisperGate destructive wiper attacks against Ukraine in early 2022.[3][4][1] There is some confusion as to whether Ember Bear overlaps with another Russian-linked entity referred to as Saint Bear. At present available evidence strongly suggests these are distinct activities with different behavioral profiles.[2][5]

APT28 is a threat group that has been attributed to Russia's General Staff Main Intelligence Directorate (GRU) 85th Main Special Service Center (GTsSS) military unit 26165.[1][2] This group has been active since at least 2004.[3][4][5][6][7][8][9][10][11][12][13]

APT28 reportedly compromised the Hillary Clinton campaign, the Democratic National Committee, and the Democratic Congressional Campaign Committee in 2016 in an attempt to interfere with the U.S. presidential election.[5] In 2018, the US indicted five GRU Unit 26165 officers associated with APT28 for cyber operations (including close-access operations) conducted between 2014 and 2018 against the World Anti-Doping Agency (WADA), the US Anti-Doping Agency, a US nuclear facility, the Organization for the Prohibition of Chemical Weapons (OPCW), the Spiez Swiss Chemicals Laboratory, and other organizations.[14] Some of these were conducted with the assistance of GRU Unit 74455, which is also referred to as Sandworm Team.

Inception is a cyber espionage group active since at least 2014. The group has targeted multiple industries and governmental entities primarily in Russia, but has also been active in the United States and throughout Europe, Asia, Africa, and the Middle East.[1][2][3]

Leviathan is a Chinese state-sponsored cyber espionage group that has been attributed to the Ministry of State Security's (MSS) Hainan State Security Department and an affiliated front company.[1] Active since at least 2009, Leviathan has targeted the following sectors: academia, aerospace/aviation, biomedical, defense industrial base, government, healthcare, manufacturing, maritime, and transportation across the US, Canada, Australia, Europe, the Middle East, and Southeast Asia.[1][2][3][4]

FIN4 is a financially-motivated threat group that has targeted confidential information related to the public financial market, particularly regarding healthcare and pharmaceutical companies, since at least 2013.[1][2] FIN4 is unique in that they do not infect victims with typical persistent malware, but rather they focus on capturing credentials authorized to access email and other non-public correspondence.[1][3]

APT29 is threat group that has been attributed to Russia's Foreign Intelligence Service (SVR).[1][2] They have operated since at least 2008, often targeting government networks in Europe and NATO member countries, research institutes, and think tanks. APT29 reportedly compromised the Democratic National Committee starting in the summer of 2015.[3][4][5][6]

In April 2021, the US and UK governments attributed the SolarWinds Compromise to the SVR; public statements included citations to APT29, Cozy Bear, and The Dukes.[7][8] Industry reporting also referred to the actors involved in this campaign as UNC2452, NOBELIUM, StellarParticle, Dark Halo, and SolarStorm.[9][10][11][12][13][14]

Medusa Group has been active since at least 2021 and was initially operated as a closed ransomware group before evolving into a Ransomware-as-a-Service (RaaS) operation. Some reporting indicates that certain attacks may still be conducted directly by the ransomware’s core developers. Public sources have also referred to the group as “Spearwing” or “Medusa Actors.” [1] [2] Medusa Group employs living-off-the-land techniques, frequently leveraging publicly available tools and common remote management software to conduct operations. The group engages in double extortion tactics, exfiltrating data prior to encryption and threatening to publish stolen information if ransom demands are not met. [3] For initial access, Medusa Group has exploited publicly known vulnerabilities, conducted phishing campaigns, and used credentials or access purchased from Initial Access Brokers (IABs). The group is opportunistic and has targeted a wide range of sectors globally. [4]

Lotus Blossom is a long-standing threat group largely targeting various entities in Asia since at least 2009. In addition to government and related targets, Lotus Blossom has also targeted entities such as digital certificate issuers.[1][2][3]

ZIRCONIUM is a threat group operating out of China, active since at least 2017, that has targeted individuals associated with the 2020 US presidential election and prominent leaders in the international affairs community.[1][2]

Volt Typhoon is a People's Republic of China (PRC) state-sponsored actor that has been active since at least 2021, primarily targeting critical infrastructure organizations in the US and its territories including Guam. Volt Typhoon's targeting and pattern of behavior have been assessed as pre-positioning to enable lateral movement to operational technology (OT) assets for potential destructive or disruptive attacks. Volt Typhoon has emphasized stealth in operations using web shells, living-off-the-land (LOTL) binaries, hands on keyboard activities, and stolen credentials.[1][2][3][4]. The group has leveraged compromised SOHO routers to proxy command and control traffic and obscure its infrastructure, activity associated with the KV botnet.[5].

Reporting indicates a separate initial access cluster, SYLVANITE, has been observed exploiting internet-facing edge devices and transferring access to Volt Typhoon, also tracked as VOLTZITE, for follow-on operations. [6]

Gamaredon Group is a suspected Russian cyber espionage group that has targeted military, law enforcement, judiciary, non-profit, and non-governmental organizations in Ukraine since at least 2013. The name Gamaredon Group derives from a misspelling of the word "Armageddon," found in early campaigns.[1][2][3][4][5]

In November 2021, the Ukrainian government publicly attributed Gamaredon Group to Russia’s Federal Security Service (FSB) Center 18, an assessment later supported by multiple independent cybersecurity researchers. [6][5]

This piece of malware steals the content of the user's keychain while maintaining a permanent backdoor [1].

MacSpy is a malware-as-a-service offered on the darkweb [1].

GreyEnergy is a backdoor written in C and compiled in Visual Studio. GreyEnergy shares similarities with the BlackEnergy malware and is thought to be the successor of it.[1]

Ursnif is a banking trojan and variant of the Gozi malware observed being spread through various automated exploit kits, Spearphishing Attachments, and malicious links.[1][2] Ursnif is associated primarily with data theft, but variants also include components (backdoors, spyware, file injectors, etc.) capable of a wide variety of behaviors.[3]

Attor is a Windows-based espionage platform that has been seen in use since 2013. Attor has a loadable plugin architecture to customize functionality for specific targets.[1]

AsyncRAT is an open-source remote access tool originally available through the NYANxCAT Github repository that has been used in malicious campaigns.[1][2][3]

Uroburos is a sophisticated cyber espionage tool written in C that has been used by units within Russia's Federal Security Service (FSB) associated with the Turla toolset to collect intelligence on sensitive targets worldwide. Uroburos has several variants and has undergone nearly constant upgrade since its initial development in 2003 to keep it viable after public disclosures. Uroburos is typically deployed to external-facing nodes on a targeted network and has the ability to leverage additional tools and TTPs to further exploit an internal network. Uroburos has interoperable implants for Windows, Linux, and macOS, employs a high level of stealth in communications and architecture, and can easily incorporate new or replacement components.[1][2]

Siloscape is malware that targets Kubernetes clusters through Windows containers. Siloscape was first observed in March 2021.[1]

SystemBC is a malware family offered as a malware-as-a-service (MaaS) that is used to establish command and control and facilitate follow-on activity, including ransomware deployment.SystemBC executes a variety of tasks including setting up SOCKS5 proxies, maintaining persistence, ingesting malicious files, and handing C2 communication. SystemBC was first detected in 2018, and has been used by Wizard Spider since at least 2020, and by FIN7 since at least 2022.[1][2][3][4][5]

Ninja is a malware developed in C++ that has been used by ToddyCat to penetrate networks and control remote systems since at least 2020. Ninja is possibly part of a post exploitation toolkit exclusively used by ToddyCat and allows multiple operators to work simultaneously on the same machine. Ninja has been used against government and military entities in Europe and Asia and observed in specific infection chains being deployed by Samurai.[1]

Tor is a software suite and network that provides increased anonymity on the Internet. It creates a multi-hop proxy network and utilizes multilayer encryption to protect both the message and routing information. Tor utilizes "Onion Routing," in which messages are encrypted with multiple layers of encryption; at each step in the proxy network, the topmost layer is decrypted and the contents forwarded on to the next node until it reaches its destination. [1]

NKAbuse is a Go-based, multi-platform malware abusing NKN (New Kind of Network) technology for data exchange between peers, functioning as a potent implant, and equipped with both flooder and backdoor capabilities.[1][2]

2025 Poland Wiper Attacks is a Russian state-sponsored campaign that conducted destructive cyberattacks against Polish energy infrastructure in December 2025. Targets included more than 30 wind and photovoltaic farms, a combined heat and power (CHP) plant, and a manufacturing sector company. The attacks on the distributed energy resources (DER) disrupted communications between affected facilities and the distribution system operator, but did not impact electricity generation or heat supply. Across the campaign, threat actors deployed two previously undocumented wiper tools, DynoWiper, a Windows-based wiper and LazyWiper, a PowerShell wiper, distributed via malicious Group Policy Objects. At the CHP plant, threat actors had maintained access since at least March 2025, using that foothold to obtain credentials and move laterally before attempting wiper deployment. Some reporting has assessed the activity to be consistent with Russian Federal Security Service (FSB) threat activity group Dragonfly, also tracked as STATIC TUNDRA, while other reporting attributes the destructive wiper activities to the Russian General Staff Main Intelligence Directorate (GRU) threat activity group ELECTRUM, also tracked as Sandworm Team.[1][2][3][4]

CostaRicto was a suspected hacker-for-hire cyber espionage campaign that targeted multiple industries worldwide, with a large number being financial institutions. CostaRicto actors targeted organizations in Europe, the Americas, Asia, Australia, and Africa, with a large concentration in South Asia (especially India, Bangladesh, and Singapore), using custom malware, open source tools, and a complex network of proxies and SSH tunnels.[1]

Operation Wocao was a cyber espionage campaign that targeted organizations around the world, including in Brazil, China, France, Germany, Italy, Mexico, Portugal, Spain, the United Kingdom, and the United States. The suspected China-based actors compromised government organizations and managed service providers, as well as aviation, construction, energy, finance, health care, insurance, offshore engineering, software development, and transportation companies.[1]

Security researchers assessed the Operation Wocao actors used similar TTPs and tools as APT20, suggesting a possible overlap. Operation Wocao was named after an observed command line entry by one of the threat actors, possibly out of frustration from losing webshell access.[1]

SPACEHOP Activity is conducted through commercially leased Virtual Private Servers (VPS), otherwise known as provisioned Operational Relay Box (ORB) networks. The network leveraged for SPACEHOP Activity enabled China-nexus cyber threat actors – such as APT5 and Ke3chang – to perform network reconnaissance scanning and vulnerability exploitation. SPACEHOP Activity has historically targeted entities in North America, Europe, and the Middle East.[1]

FLORAHOX Activity is conducted using a hybrid operational relay box (ORB) network, which combines two types of infrastructure: compromised devices and leased Virtual Private Servers (VPS). The compromised devices include end-of-life routers and IoT devices, while VPS space is commercially leased and managed by ORB network administrators. This hybrid ORB network allows adversaries to proxy and obscure malicious traffic, making the source of the traffic more difficult to trace.

The FLORAHOX ORB network has been leveraged by multiple cyber threat actors, including China-nexus actors like ZIRCONIUM. These adversaries conduct espionage campaigns through FLORAHOX Activity, relying on the ORB network's ability to funnel traffic through Tor nodes, provisioned VPS servers, and compromised routers to obfuscate malicious traffic.[1]

The Salesforce Data Exfiltration campaign began in October 2024 with financially-motivated threat actor UNC6040 using Spearphishing Voice (vishing) to compromise corporate Salesforce instances for large-scale data theft and extortion. Following the initial data theft, victim organizations received extortion demands from a separate threat actor, UNC6240, who claimed to be the “ShinyHunters” group. The observed infrastructure and TTPs used during the Salesforce Data Exfiltration campaign overlap with those used by threat groups with suspected ties to the broader collective known as "The Com.” These overlaps could plausibly be the result of associated actors operating within the same communities and are not necessarily an indication of a direct operational relationship.[1][2]

Quad7 Activity, also known as CovertNetwork-1658 or the 7777 Botnet, is a network of compromised small office/home office (SOHO) routers. [1] [2] The botnet was initially composed primarily of TP-Link routers and was named Quad7 due to compromised devices exposing TCP port 7777 with the distinctive banner xlogin. Later activity showed a significant increase in compromised Asus routers and the addition of new ports and banners, including TCP port 63256 displaying alogin. Quad7 infrastructure functions as a collection of egress IPs that various China-affiliated threat actors have used to conduct password-spraying and brute-force operations. [1][3] Microsoft has reported that Storm-0940 leveraged credentials obtained through Quad7 Activity to target organizations in North America and Europe, including government agencies, non-governmental organizations, think tanks, law firms, energy firms, IT providers, and defense industrial base entities. [2]

The RedPenguin project was launched by Juniper in July 2024 to investigate reported malware infections of Juniper MX Series routers. RedPenguin activity was separately attributed to UNC3886 and included the deployment of multiple custom versions of the publicly-available TINYSHELL backdoor on Juniper routers.[1][2]