ShelbyLoader / ShelbyC2

Adversaries may abuse PowerShell commands and scripts for execution. PowerShell is a powerful interactive command-line interface and scripting environment included in the Windows operating system. Adversaries can use PowerShell to perform a number of actions, including discovery of information and execution of code. Examples include the <code>Start-Process</code> cmdlet which can be used to run an executable and the <code>Invoke-Command</code> cmdlet which runs a command locally or on a remote computer (though administrator permissions are required to use PowerShell to connect to remote systems).

Evidence: 2026-10-07/cl-sta-1178-blinder-tunnel-csproj-lure-github-c2 · ATT&CK page ↗

Adversaries may use MSBuild to proxy execution of code through a trusted Windows utility. MSBuild.exe (Microsoft Build Engine) is a software build platform used by Visual Studio. It handles XML formatted project files that define requirements for loading and building various platforms and configurations.

Evidence: 2026-10-07/cl-sta-1178-blinder-tunnel-csproj-lure-github-c2 · ATT&CK page ↗

An adversary may rely upon a user opening a malicious file in order to gain execution. Users may be subjected to social engineering to get them to open a file that will lead to code execution. This user action will typically be observed as follow-on behavior from Spearphishing Attachment. Adversaries may use several types of files that require a user to execute them, including .doc, .pdf, .xls, .rtf, .scr, .exe, .lnk, .pif, .cpl, .reg, and .iso.

Evidence: 2026-10-07/cl-sta-1178-blinder-tunnel-csproj-lure-github-c2 · ATT&CK page ↗

Adversaries may abuse dynamic-link library files (DLLs) in order to achieve persistence, escalate privileges, and evade defenses. DLLs are libraries that contain code and data that can be simultaneously utilized by multiple programs. While DLLs are not malicious by nature, they can be abused through mechanisms such as side-loading, hijacking search order, and phantom DLL hijacking.

Evidence: 2026-10-07/cl-sta-1178-blinder-tunnel-csproj-lure-github-c2 · ATT&CK page ↗

Adversaries may execute their own malicious payloads by hijacking how the .NET `AppDomainManager` loads assemblies. The .NET framework uses the `AppDomainManager` class to create and manage one or more isolated runtime environments (called application domains) inside a process to host the execution of .NET applications. Assemblies (`.exe` or `.dll` binaries compiled to run as .NET code) may be loaded into an application domain as executable code.

Evidence: 2026-10-07/cl-sta-1178-blinder-tunnel-csproj-lure-github-c2 · ATT&CK page ↗

Adversaries may achieve persistence by adding a program to a startup folder or referencing it with a Registry run key. Adding an entry to the "run keys" in the Registry or startup folder will cause the program referenced to be executed when a user logs in. These programs will be executed under the context of the user and will have the account's associated permissions level.

Evidence: 2026-10-07/cl-sta-1178-blinder-tunnel-csproj-lure-github-c2 · ATT&CK page ↗

Adversaries may achieve persistence by adding a program to a startup folder or referencing it with a Registry run key. Adding an entry to the "run keys" in the Registry or startup folder will cause the program referenced to be executed when a user logs in. These programs will be executed under the context of the user and will have the account's associated permissions level.

Evidence: 2026-10-07/cl-sta-1178-blinder-tunnel-csproj-lure-github-c2 · ATT&CK page ↗

Adversaries may attempt to make an executable or file difficult to discover or analyze by encrypting, encoding, or otherwise obfuscating its contents on the system or in transit. This is common behavior that can be used across different platforms and the network to evade defenses.

Evidence: 2026-10-07/cl-sta-1178-blinder-tunnel-csproj-lure-github-c2 · ATT&CK page ↗

Adversaries may match or approximate the name or location of legitimate files, Registry keys, or other resources when naming/placing them. This is done for the sake of evading defenses and observation.

Evidence: 2026-10-07/cl-sta-1178-blinder-tunnel-csproj-lure-github-c2 · ATT&CK page ↗

Adversaries may use MSBuild to proxy execution of code through a trusted Windows utility. MSBuild.exe (Microsoft Build Engine) is a software build platform used by Visual Studio. It handles XML formatted project files that define requirements for loading and building various platforms and configurations.

Evidence: 2026-10-07/cl-sta-1178-blinder-tunnel-csproj-lure-github-c2 · ATT&CK page ↗

Adversaries may abuse dynamic-link library files (DLLs) in order to achieve persistence, escalate privileges, and evade defenses. DLLs are libraries that contain code and data that can be simultaneously utilized by multiple programs. While DLLs are not malicious by nature, they can be abused through mechanisms such as side-loading, hijacking search order, and phantom DLL hijacking.

Evidence: 2026-10-07/cl-sta-1178-blinder-tunnel-csproj-lure-github-c2 · ATT&CK page ↗

Adversaries may execute their own malicious payloads by hijacking how the .NET `AppDomainManager` loads assemblies. The .NET framework uses the `AppDomainManager` class to create and manage one or more isolated runtime environments (called application domains) inside a process to host the execution of .NET applications. Assemblies (`.exe` or `.dll` binaries compiled to run as .NET code) may be loaded into an application domain as executable code.

Evidence: 2026-10-07/cl-sta-1178-blinder-tunnel-csproj-lure-github-c2 · ATT&CK page ↗

Adversaries may disable, degrade, or tamper with security tools or applications (e.g., endpoint detection and response (EDR) tools, intrusion detection systems (IDS), antivirus, logging agents, sensors, etc.) to impair or reduce visibility of defensive capabilities. This may include stopping specific services, killing processes, modifying or deleting tool configuration files and Registry keys, or preventing tools from updating. This may also include impairing defenses more broadly by disrupting preventative, detection, and response mechanisms across host, network, and cloud environments.

Evidence: 2026-10-07/cl-sta-1178-blinder-tunnel-csproj-lure-github-c2 · ATT&CK page ↗

Adversaries may use an existing, legitimate external Web service to host information that points to additional command and control (C2) infrastructure. Adversaries may post content, known as a dead drop resolver, on Web services with embedded (and often obfuscated/encoded) domains or IP addresses. Once infected, victims will reach out to and be redirected by these resolvers.

Evidence: 2026-10-07/cl-sta-1178-blinder-tunnel-csproj-lure-github-c2 · ATT&CK page ↗

Adversaries may use an existing, legitimate external Web service as a means for sending commands to and receiving output from a compromised system over the Web service channel. Compromised systems may leverage popular websites and social media to host command and control (C2) instructions. Those infected systems can then send the output from those commands back over that Web service channel. The return traffic may occur in a variety of ways, depending on the Web service being utilized. For example, the return traffic may take the form of the compromised system posting a comment on a forum, issuing a pull request to development project, updating a document hosted on a Web service, or by sending a Tweet.

Evidence: 2026-10-07/cl-sta-1178-blinder-tunnel-csproj-lure-github-c2 · ATT&CK page ↗

Adversaries may tunnel network communications to and from a victim system within a separate protocol to avoid detection/network filtering and/or enable access to otherwise unreachable systems. Tunneling involves explicitly encapsulating a protocol within another. This behavior may conceal malicious traffic by blending in with existing traffic and/or provide an outer layer of encryption (similar to a VPN). Tunneling could also enable routing of network packets that would otherwise not reach their intended destination, such as SMB, RDP, or other traffic that would be filtered by network appliances or not routed over the Internet.

Evidence: 2026-10-07/cl-sta-1178-blinder-tunnel-csproj-lure-github-c2 · ATT&CK page ↗