Microsoft Warns Secret Blizzard Hackers Target Foreign Embassies with ISP-Level Attacks to Install Malicious TLS Root Certificate

A Russian state-backed hacking operation has been observed targeting foreign embassies in Moscow through sophisticated adversary-in-the-middle techniques deployed at the Internet Service Provider (ISP) level. The campaign, active since the previous year, leverages control over local telecommunications networks to position the attackers between embassy endpoints and their intended destinations. This enables the deployment of a custom surveillance payload that culminates in the installation of a TLS root certificate, allowing the threat actors to cryptographically impersonate trusted websites visited by an infected system. The activity highlights a troubling expansion in the capabilities of Secret Blizzard to operate within the Russian internet infrastructure, with diplomats and related personnel identified as highly likely targets when using domestic ISPs or telecom services. This article provides a thorough, engineered breakdown of the campaign, the infection chain, the technical mechanisms in play, the potential impact on diplomatic security, and recommended defensive measures for organizations most at risk.

Campaign Context and Scope

Secret Blizzard, a state-sponsored hacking collective with a long and complex history, has emerged as one of the more active and technically sophisticated groups in the global cyber espionage landscape. The group has been tracked across various code names and aliases, reflecting its evolution and the breadth of its operations. In this recent campaign, Microsoft’s Threat Intelligence team has flagged the group’s activities as targeting foreign embassies operating in Moscow through a novel, ISP-level adversary-in-the-middle (AiTM) approach. This technique represents a shift from classic endpoint-focused intrusions to a broader geostrategic operation that leverages the trusted channels of state-controlled or state-influenced networks.

The operation relies on the attackers’ ability to insert themselves into the path between embassy devices and remote endpoints they connect to. By occupying such a strategic position within the ISPs serving Russia, Secret Blizzard can redirect traffic to attacker-controlled resources, all while the user remains unaware of the interception. The endgame of the campaign centers on stealthy software deployment—specifically, a malicious payload named ApolloShadow—that, once installed, proceeds to install a TLS root certificate. This certificate issuance enables the group to impersonate legitimate, trusted sites encountered by an infected machine within the embassy network. In essence, the attackers gain the capability to decrypt and re-encrypt communications in a manner that appears perfectly legitimate to the target, thereby enabling covert data collection, credential harvesting, and other espionage objectives.

The scope of the operation, as described by Microsoft, emphasizes a targeted approach toward diplomatic personnel who access the internet through Russia’s domestic ISPs or telecom services. The threat model assumes a high-value target set—diplomatic staff and embassy users who routinely engage in sensitive communications and access critical government information. The implications are significant: if adversaries can observe, alter, or impersonate communications from embassies, they can potentially access confidential information, undermine diplomatic channels, and gather intelligence with a higher degree of confidence.

In terms of actor profiling, Secret Blizzard is widely understood to be a high-end, state-aligned group with deep resources and technical prowess. The group has a long operational history and has been associated with a spectrum of cyber espionage campaigns observed by security researchers and government agencies. The current campaign underscores the group’s willingness to deploy highly targeted, supply-chain-like theater within geographic and political boundaries, exploiting the unique controls and trust relationships embedded in Russia’s internet infrastructure. The corporate and government sectors that maintain sensitive operations in Moscow are among the most at risk, given that the attackers have demonstrated the ability to operate at the ISP level and to manipulate user experiences through legitimate network mechanisms like captive portals and standard connectivity checks.

The broader security narrative here is clear: when an adversary can influence the network layer between a host and the wider internet, it becomes much harder to detect interventions that occur before traffic ever reaches an endpoint-based security appliance. The embedded risk for embassies arises not only from data exfiltration but from the ability to present forged, certificate-validated content that appears legitimate to the user. The campaign’s effectiveness lies in the combination of a credible intrusion framework, the exploitation of trusted channels, and a carefully staged user interaction that prompts installation of the ApolloShadow payload and its root-certificate mechanism.

To understand the gravity of the situation, it is essential to recognize that the AiTM position is inherently trusted by the user, because it leverages legitimate internet-facing behavior. The captive portal technique, a common, legitimate method used in hospitality and transportation networks to manage access, provides the attackers with a familiar user experience, reducing suspicion. Once a target device is steered through a captive portal, the infection chain proceeds through a series of well-orchestrated steps designed to maximize the likelihood of user interaction, credential exposure, and persistence within the host system. The campaign’s use of the Windows Test Connectivity Status Indicator (TCSI) and subsequent redirection to attacker-controlled resources illustrates a precise exploitation of operating system behaviors to facilitate payload delivery.

In summary, the campaign represents a strategic, state-backed intrusion into the embassy ecosystem, leveraging both network-layer manipulation and sophisticated malware to achieve long-term access and intelligence collection. The focus on ISPs and telecom providers in Russia shows a calculated preference for leveraging trusted, regime-aligned infrastructures to minimize detection risk while maximizing the potential for effective surveillance. The implications for diplomatic security are profound, requiring a reevaluation of how sensitive communications are transmitted and protected within environments that may be influenced by hostile actors at the network layer.

The ApolloShadow Objective and Its Significance

ApolloShadow is the malware payload at the heart of the campaign’s objective: to install a TLS root certificate on compromised systems, enabling Secret Blizzard to perform cryptographic impersonation of any visited, legitimate websites. This capability is central to the group’s ability to monitor, intercept, and manipulate secure communications without triggering standard security alerts. The root certificate gives the attackers an extraordinary level of access to encrypted traffic, allowing them to decrypt and re-encrypt communications with the attacker’s certs in place. In practice, this means that encrypted sessions to banking sites, email services, government portals, and other sensitive endpoints can be rendered visible to the attackers, who can then extract credentials, intellectual property, or other confidential data.

From a defensive perspective, the installation of a trusted root certificate is one of the most concerning artifacts of a successful intrusion. Root certificates are designed to be highly sensitive and resilient components of the trust store on a device. Once a malicious root certificate is trusted by the system, it can facilitate man-in-the-middle activities across encrypted channels with little to no user-visible indicators. This is precisely why the campaign’s use of ApolloShadow to install a root certificate is so consequential: it paves the way for prolonged, covert access to communications and data on compromised machines.

The strategic aim behind ApolloShadow is espionage and information gathering, not immediate disruption. By obtaining a position of trust in the host’s crypto stack, the group can maximize opportunities to observe ongoing diplomatic communications, check configurations, collect credentials, and map organizational networks. ApolloShadow’s operational life cycle demonstrates a sophisticated understanding of Windows security, user consent prompts, and how to leverage legitimate-looking installer artifacts to legitimize elevated actions. The threat actor’s ability to pivot from a user-facing prompt to deep system trust embodies a multi-stage approach that is designed to minimize user suspicion while ensuring that the certificate remains in place across sessions.

The broader significance of this objective is twofold. First, it signals a mature capability to conduct long-term surveillance within high-value institutions operating in Russia, especially where traffic may be routed through domestic providers. Second, it underscores a vulnerability in the security model of standard enterprise and diplomatic networks: even sophisticated defense postures may be subtly undermined by trusted components of the system being compromised. The malware’s credential theft and data exfiltration potential are amplified by the fact that an installed certificate enables a trusted position that bypasses many endpoint defenses and network controls.

The operational design of ApolloShadow shows an emphasis on stealth and persistence. The installer components are crafted to masquerade as legitimate software, leveraging common Windows mechanisms to prompt privilege elevation and user consent. Once the root certificate is in place, the ongoing surveillance becomes less about a single breach and more about a persistent foothold that can be leveraged in multiple campaigns or extended diplomatic sessions. The knowledge that such a tool can be deployed in a targeted setting, such as embassies, highlights the need for heightened vigilance in environments where government communications are most sensitive and where adversaries have demonstrated the capability to exploit the trusted channels that users rely on daily.

Infection Chain and Delivery Vectors

The infection chain begins with the adversary-in-the-middle position within the domestic ISP ecosystem, a vantage point that allows the attackers to intercept, redirect, and influence user experiences. The campaign’s initial access vector draws on the credibility of captive portals, a widely deployed mechanism for controlled internet access in hospitality, travel hubs, and other public settings. In the observed operation, targets connected to a network with a captive portal, after which the standard user flow—authentication, acceptance of terms, or payment prompts—becomes a conduit for the next stage of exploitation.

The first technical pivot occurs when the captive portal initiates the Windows Test Connectivity Status Indicator (TCSI), a legitimate Windows service designed to verify internet connectivity. The TCSI traffic then redirects to a legitimate-seeming page on a Microsoft domain, which in turn pushes the browser toward a malicious domain controlled by the attackers. This chain of redirects and the use of a reputable test connectivity service create a plausible sequence that reduces user suspicion and increases the likelihood that the user will engage with the content rendered by the attacker-controlled site.

Upon reaching the attacker-controlled environment, the user is shown a certificate validation error prompt that prompts them to download and execute ApolloShadow. The malware’s delivery hinges on user interaction with this prompt, leveraging a social engineering aspect that has historically proven effective against unsuspecting users in high-stakes environments. After the user executes ApolloShadow, the malware begins its privilege escalation process, which includes checking the token rights of the current process. ApolloShadow uses the GetTokenInformationType API to determine whether it has sufficient system rights to install a root certificate. If it determines it lacks these rights, the payload proceeds through a sophisticated workaround.

A critical step in this workaround involves a second-stage payload encoded within a VBScript that is delivered by spoofing a page on a legitimate certificate-related website. The spoofed page is designed to be trusted by the browser and to push a second-stage payload into the system, enabling the malware to relaunch itself with greater privileges. When the payload reincarnates, it presents the user with another User Account Control (UAC) prompt that asks for permission to elevate to the required level of access. The file name—CertificateDB.exe—functions as a disguise, presenting itself as a Kaspersky installer to install root certificates and grant the attacker elevated privileges.

Once ApolloShadow gains sufficient privileges, the malware proceeds to perform a configuration sequence that extends beyond mere certificate installation. It configures all networks the host connects to as private, a move that has significant implications for security posture. By marking networks as private, the host becomes more discoverable on the local network and firewall rules are relaxed to enable file sharing. Microsoft’s account of this technique emphasizes that these modifications are intended to reduce the difficulty of potential lateral movement within the environment. While there is no immediate evidence of active lateral movement in the described instance, the changes create an environment more conducive to later-stage intrusions, data exfiltration, or further persistence mechanisms.

In parallel with privilege escalation and network reconfiguration, ApolloShadow installs the root certificate to enable trust in attacker-hosted content and to maintain a persistent, covert capacity for monitoring and interception of traffic. The root certificate allows the actor to decrypt SSL/TLS traffic and to re-encrypt it so that communications to legitimate sites proceed with the attacker in the middle. The net effect is a highly persistent, stealthy foothold that can function across reboots and user profiles, enabling long-term intelligence efforts aligned with the threat actor’s objectives.

The infection chain’s design reflects several core operational principles: deception, trust exploitation, privilege escalation, and a reduction of defensive friction. The use of a legitimate Windows service followed by a UAC prompt and a disguised executable demonstrates an effort to align with widely trusted software behavior, increasing the probability that users will consent to actions that are, in reality, malicious. The attackers’ ability to manipulate captive portal workflows and to leverage legitimate connectivity checks underscores a high level of sophistication in exploiting normal network operations for their purposes.

Adversary-In-The-Middle Technique at ISP Level

The AiTM approach deployed by Secret Blizzard represents a strategic shift in how the attackers target their victims. By positioning themselves in the path of the victim’s traffic at the ISP level, they can orchestrate a controlled, pre-emptive interception of communications, creating an environment that is conducive to manipulation and subversion of trust. This technique depends on access or influence over the routing and filtering policies carried out by the ISP or by allied infrastructure. In practice, the attackers can present themselves as a legitimate intermediary that the user unknowingly trusts, allowing them to redirect traffic, inject content, or present warning signals that prompt the user to install software or visit attacker-controlled domains.

The AiTM method is particularly effective for espionage campaigns against high-value targets such as foreign embassies because it addresses a fundamental challenge: gaining visibility into encrypted communications without alerting a modern security stack. By controlling the point where traffic is decrypted and re-encrypted, the attackers can operate with reduced risk of immediate discovery. When a target navigates to a secure site, the AiTM attacker’s control can present a certificate that the user perceives as legitimate, provided that the attacker has successfully installed and configured a trusted root certificate on the system.

In this campaign, the AiTM position is complemented by the captive portal tactic, which creates a transitional network environment where the user is effectively inside a controlled entry point, from which the attacker can guide the user toward the malicious payload. The combination of contextually precise redirections, authenticated portal prompts, and the use of a Windows-based credential and certificate flow creates a cohesive chain that is difficult to disrupt without active, network-level protections. The result is a stealthy, location-aware operation that leverages both network infrastructure and client-side behaviors to facilitate the installation of ApolloShadow and the subsequent root certificate.

Infection Chain and Delivery Details: The Windows Lifecycle

A closer look at the infection chain reveals a multi-stage lifecycle that is deliberately constructed to maximize the chance of a successful compromise. The first stage relies on a user-facing presentation that leverages a familiar Windows connectivity check and a seemingly legitimate redirect to trusted domains. The second stage is a code delivery and privilege escalation sequence designed to procure the necessary authorization to install a root certificate and adjust network settings.

Key technical points in this chain include:

• The Windows Test Connectivity Status Indicator (TCSI) is triggered as the user’s browser session is manipulated, providing a pathway for the malware to redirect the user’s browser. The TCSI mechanism is widely accepted as a legitimate Windows feature, which the attacker leverages to justify the traffic redirection and the subsequent plunge into attacker-controlled web resources.

• The attacker-controlled domain involved in the redirection likely displays a certificate validation error, a facade used to prompt the user to download and run ApolloShadow. This design relies on the user’s belief that something is amiss with the security of the site and that running a legitimate-looking installer is a reasonable corrective action.

• Following execution, ApolloShadow checks the system’s privilege level. If the process is not running with the necessary administrative privileges to install a root certificate, the malware uses a layered approach to escalate privileges. The second-stage payload is delivered via a VBScript encoded and executed behind a spoofed page at a legitimate certificate authority domain, such as a timestamp verification page. Decoding and execution of the VBScript cause the malware to relaunch itself and present a second UAC prompt to the user to facilitate elevation.

• Once elevated, ApolloShadow configures the device so that all networks it connects to are treated as private. This configuration change has notable implications for security posture: it reduces the likelihood of interference from firewall rules, increases network discoverability, and facilitates potential lateral movement across connected systems. Although Microsoft did not observe direct lateral movement in the described incident, this configuration change clearly lowers barriers to later-stage intrusions and data dissemination.

• The root certificate installation phase is the culmination of the infection chain. By inserting a trusted issuer into the system’s trust store, the attackers can decrypt and re-encrypt TLS traffic, enabling impersonation of any site the user visits. In effect, the attacker can observe sensitive communications, credentials, or other secrets that transit through the compromised host. The persistence of such a certificate presents a long-term risk, particularly for embassies and other high-sensitivity entities operating under domestic network conditions.

• The entire infection chain demonstrates a careful balance between user interaction and system manipulation. The social engineering component—prompting users to install a certificate-issuing component under the guise of legitimate security checks—works synergistically with the technical means of privilege escalation and network reconfiguration. The outcome is a robust foothold that can survive typical endpoint defenses and be leveraged for extended intelligence operations.

In practical terms, the infection chain shows how a highly targeted espionage campaign can exploit standard network features and legitimate system components to bypass traditional security controls. It also underscores the importance of monitoring for unusual root certificate installations, unexpected network reconfigurations, and suspicious prompts that request elevated privileges or the installation of third-party software.

Defensive Implications and Risk Mitigation for High-Risk Organizations

The emergence of an ISP-level AiTM operation with ApolloShadow in the context of foreign embassies compels a recalibration of defensive postures for high-risk organizations, especially those operating in geopolitically tense environments. The following defensive considerations and mitigations are recommended to reduce the risk of similar campaigns succeeding:

• Implement strict control over root certificates. Organizations should enforce least-privilege policies and apply rigorous controls around the installation and management of root certificates. Regularly audit the certificate store to detect unexpected additions, revoke suspicious certificates, and enforce policy-driven remediation for unauthorized changes.

• Harden privilege elevation processes. UAC and associated elevation prompts can be manipulated during complex infection chains. Enforce stricter application control policies, require admin approvals for non-standard actions, and deploy credential vaults and Just-In-Time (JIT) privilege elevation to minimize the window of opportunity for malware to acquire elevated rights.

• Strengthen network segmentation and isolation. Segment networks to limit lateral movement and reduce exposure from any single compromised host. Critical diplomatic workstations and embassy networks should be placed on restricted segments with tightly controlled inter-network traffic, monitored for anomalous behavior, and protected by strict egress controls.

• Scrutinize captive portal environments. While captive portals are legitimate, they can be exploited to direct users toward malicious resources. Organizations should monitor and validate captive portal interactions and implement compensating controls, such as traffic normalization or DNS filtering within the portal environment to prevent redirection to attacker-controlled domains.

• Monitor Windows connectivity workflows and certificate-related activity. Security teams should implement telemetry around Windows test connectivity checks, TLS handshake anomalies, and suspicious attempts to install certificates or modify the trust store. SIEM rules should alert on anomalous sequences such as unexpected certificate installations, repeated UAC prompts tied to certificate installation, or changes to the network profile from public to private in short time frames.

• Harden capabilities against toolchains that masquerade as legitimate software. The ApolloShadow delivery chain shows how attackers use legitimate-looking installers to gain trust. Deploy application whitelisting, robust integrity checks on installers, and behavior-based detection for suspicious credential prompts or unusual system modifications.

• Emphasize user education and awareness in high-risk contexts. Diplomats and staff should receive targeted training on recognizing social engineering prompts that resemble legitimate system prompts, including certificate alerts or prompts that instruct users to install security-related software. Simulations and drills can help personnel respond appropriately to suspicious prompts and avoid inadvertently empowering attackers.

• Use end-to-end encryption and secure channels for sensitive communications. Even when devices are potentially compromised, encryption in transit and at rest reduces the value of stolen data. Organizations should consider strong, authenticated encryption for critical channels and ensure that endpoint security complements, rather than depends on, network-layer protections.

• Deploy endpoint detection and response (EDR) with robust certificate-trust monitoring. EDR tools should be configured to monitor for root cert changes, the execution of installers masquerading as legitimate software, and unusual network behavior following certificate installation. Anomalies such as sudden trust store expansions, unusual process tokens, or unexpected network reconfiguration should trigger immediate investigation.

• Establish an incident response playbook tailored to AiTM-style threats. Given the unique network-layer risk presented by AiTM campaigns, incident response protocols should incorporate network forensics, certificate store audits, and rapid containment strategies to remove compromised devices from the network while preserving forensic data for analysis.

• Consider geopolitical and vendor risk management implications. Organizations with embassy operations or diplomatic staff should assess third-party service providers that may have access to critical network paths. Vendor risk management should evaluate the security posture of ISPs and telecommunication partners and consider contractual safeguards that enhance resilience against network-layer intrusions.

These mitigations, while comprehensive, require coordinated implementation across network, endpoint, and identity teams. The goal is to disrupt the attack chain at multiple points—before, during, and after an AiTM-based intrusion—while maintaining the ability to operate securely in high-risk environments.

Threat Actor Profile: Secret Blizzard

Secret Blizzard is widely recognized in the threat intelligence community as one of the most active state-sponsored groups involved in cyber espionage operations. The group is commonly attributed to a unit within the Russian Federal Security Service (FSB) and has a long history of activity that stretches back to the late 1990s. Over the years, the group has accrued a reputation for developing and deploying sophisticated malware families and employing advanced intrusion techniques, often in the service of national security objectives. The group’s alias repertoire includes a number of names that security researchers have used to track its various campaigns and evolutions. Among the names associated with the group are Turla, Venomous Bear, Uroburos, Snake, Blue Python, Wraith, ATG26, and Waterbug. These aliases reflect the group’s broad and evolving tooling ecosystem, as well as the complexity of attribution in contemporary cyber operations.

According to official governmental and cybersecurity risk assessments, Secret Blizzard has been characterized as a high-capability threat actor with a focus on cyber espionage that targets government entities, critical infrastructure, and other high-value sectors. Its campaigns are typically well-resourced, employing a mix of targeted phishing, supply-chain-like intrusions, zero-day or custom exploit usage, and robust post-exploitation frameworks designed to maintain persistence and provide ongoing access. The group’s affiliation with state security apparatus adds a strategic dimension to its operations, as the objectives often align with national security interests that transcend ordinary criminal operations.

The current campaign against foreign embassies in Moscow is consistent with Secret Blizzard’s apparent emphasis on intelligence collection, including diplomatic intelligence, political insights, and other sensitive data that can enable strategic decision-making. The use of AiTM techniques at the ISP level represents an escalation in capability—moving beyond merely compromising endpoints to manipulating the user’s entire connectivity environment. The group’s adoption of ApolloShadow demonstrates a willingness to develop custom payloads tailored to the specifics of the environment in which the operation occurs, including the exploitation of Windows infrastructure through legitimate services and credential workflows.

From a defensive perspective, understanding Secret Blizzard’s capabilities, tactics, techniques, and procedures (TTPs) is essential to building resilient security postures. The group’s willingness to exploit trusted pathways, to invest in persistent root certificate deployments, and to combine network-layer manipulation with client-side social engineering creates a multi-layered threat that requires comprehensive, cross-domain defense strategies. Stakeholders in organizations with high-risk exposure should monitor for indicators associated with this actor, including signs of AiTM activity, suspicious root certificate installations, unexpected network reconfigurations, and the use of disguised installers that mimic legitimate software.

Conclusion

The discovery of the Secret Blizzard operation targeting foreign embassies in Moscow through ISP-level adversary-in-the-middle techniques, culminating in ApolloShadow’s root certificate deployment, marks a significant escalation in state-sponsored cyber espionage. The campaign illustrates a highly integrated attack chain that leverages captive portals, legitimate Windows services, privilege escalation, and network-level manipulation to create a persistent foothold for intelligence gathering. The strategic objective—implanting a trusted root certificate to enable decryption and impersonation of secure communications—presents a profound risk for diplomatic security and sensitive governmental operations in environments where domestic networks and providers can be used to influence traffic.

To mitigate these threats, organizations must implement multi-layered defenses that combine strict privilege management, vigilant monitoring of certificate stores, robust network segmentation, and proactive user education. The AiTM approach is particularly challenging because it exploits trust in network infrastructure and legitimate features of modern operating systems. A coordinated defense that spans network controls, endpoint protection, identity verification, and incident response will be essential to detect, deter, and disrupt this kind of campaign. By understanding the mechanics of ApolloShadow, the intricacies of the infection chain, and the strategic aims of Secret Blizzard, defenders can build stronger safeguards that protect diplomatic communications, preserve operational integrity, and reduce the likelihood of successful, long-term intrusions of this nature.