Malware Siloscape

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


List of techniques used :


id description
T1027 Obfuscated Files or Information
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. Payloads may be compressed, archived, or encrypted in order to avoid detection. These payloads may be used during Initial Access or later to mitigate detection. Sometimes a user's action may be required to open and Deobfuscate/Decode Files or Information for User Execution. The user may also be required to input a password to open a password protected compressed/encrypted file that was provided by the adversary. Adversaries may also use compressed or archived scripts, such as JavaScript. Portions of files can also be encoded to hide the plain-text strings that would otherwise help defenders with discovery. Payloads may also be split into separate, seemingly benign files that only reveal malicious functionality when reassembled. Adversaries may also abuse Command Obfuscation to obscure commands executed from payloads or directly via Command and Scripting Interpreter. Environment variables, aliases, characters, and other platform/language specific semantics can be used to evade signature based detections and application control mechanisms.
T1059.003 Command and Scripting Interpreter: Windows Command Shell
Adversaries may abuse the Windows command shell for execution. The Windows command shell (cmd) is the primary command prompt on Windows systems. The Windows command prompt can be used to control almost any aspect of a system, with various permission levels required for different subsets of commands. The command prompt can be invoked remotely via Remote Services such as SSH. Batch files (ex: .bat or .cmd) also provide the shell with a list of sequential commands to run, as well as normal scripting operations such as conditionals and loops. Common uses of batch files include long or repetitive tasks, or the need to run the same set of commands on multiple systems. Adversaries may leverage cmd to execute various commands and payloads. Common uses include cmd to execute a single command, or abusing cmd interactively with input and output forwarded over a command and control channel.
T1068 Exploitation for Privilege Escalation
Adversaries may exploit software vulnerabilities in an attempt to elevate privileges. Exploitation of a software vulnerability occurs when an adversary takes advantage of a programming error in a program, service, or within the operating system software or kernel itself to execute adversary-controlled code. Security constructs such as permission levels will often hinder access to information and use of certain techniques, so adversaries will likely need to perform privilege escalation to include use of software exploitation to circumvent those restrictions. When initially gaining access to a system, an adversary may be operating within a lower privileged process which will prevent them from accessing certain resources on the system. Vulnerabilities may exist, usually in operating system components and software commonly running at higher permissions, that can be exploited to gain higher levels of access on the system. This could enable someone to move from unprivileged or user level permissions to SYSTEM or root permissions depending on the component that is vulnerable. This could also enable an adversary to move from a virtualized environment, such as within a virtual machine or container, onto the underlying host. This may be a necessary step for an adversary compromising an endpoint system that has been properly configured and limits other privilege escalation methods. Adversaries may bring a signed vulnerable driver onto a compromised machine so that they can exploit the vulnerability to execute code in kernel mode. This process is sometimes referred to as Bring Your Own Vulnerable Driver (BYOVD). Adversaries may include the vulnerable driver with files delivered during Initial Access or download it to a compromised system via Ingress Tool Transfer or Lateral Tool Transfer.
T1069 Permission Groups Discovery
Adversaries may attempt to discover group and permission settings. This information can help adversaries determine which user accounts and groups are available, the membership of users in particular groups, and which users and groups have elevated permissions. Adversaries may attempt to discover group permission settings in many different ways. This data may provide the adversary with information about the compromised environment that can be used in follow-on activity and targeting.
T1071 Application Layer Protocol
Adversaries may communicate using OSI application layer protocols to avoid detection/network filtering by blending in with existing traffic. Commands to the remote system, and often the results of those commands, will be embedded within the protocol traffic between the client and server. Adversaries may utilize many different protocols, including those used for web browsing, transferring files, electronic mail, DNS, or publishing/subscribing. For connections that occur internally within an enclave (such as those between a proxy or pivot node and other nodes), commonly used protocols are SMB, SSH, or RDP.
T1083 File and Directory Discovery
Adversaries may enumerate files and directories or may search in specific locations of a host or network share for certain information within a file system. Adversaries may use the information from File and Directory Discovery during automated discovery to shape follow-on behaviors, including whether or not the adversary fully infects the target and/or attempts specific actions. Many command shell utilities can be used to obtain this information. Examples include dir, tree, ls, find, and locate. Custom tools may also be used to gather file and directory information and interact with the Native API. Adversaries may also leverage a Network Device CLI on network devices to gather file and directory information (e.g. dir, show flash, and/or nvram). Some files and directories may require elevated or specific user permissions to access.
T1090.003 Proxy: Multi-hop Proxy
Adversaries may chain together multiple proxies to disguise the source of malicious traffic. Typically, a defender will be able to identify the last proxy traffic traversed before it enters their network; the defender may or may not be able to identify any previous proxies before the last-hop proxy. This technique makes identifying the original source of the malicious traffic even more difficult by requiring the defender to trace malicious traffic through several proxies to identify its source. For example, adversaries may construct or use onion routing networks – such as the publicly available Tor network – to transport encrypted C2 traffic through a compromised population, allowing communication with any device within the network. Adversaries may also use operational relay box (ORB) networks composed of virtual private servers (VPS), Internet of Things (IoT) devices, smart devices, and end-of-life routers to obfuscate their operations. In the case of network infrastructure, it is possible for an adversary to leverage multiple compromised devices to create a multi-hop proxy chain (i.e., Network Devices). By leveraging Patch System Image on routers, adversaries can add custom code to the affected network devices that will implement onion routing between those nodes. This method is dependent upon the Network Boundary Bridging method allowing the adversaries to cross the protected network boundary of the Internet perimeter and into the organization’s Wide-Area Network (WAN). Protocols such as ICMP may be used as a transport. Similarly, adversaries may abuse peer-to-peer (P2P) and blockchain-oriented infrastructure to implement routing between a decentralized network of peers.
T1106 Native API
Adversaries may interact with the native OS application programming interface (API) to execute behaviors. Native APIs provide a controlled means of calling low-level OS services within the kernel, such as those involving hardware/devices, memory, and processes. These native APIs are leveraged by the OS during system boot (when other system components are not yet initialized) as well as carrying out tasks and requests during routine operations. Adversaries may abuse these OS API functions as a means of executing behaviors. Similar to Command and Scripting Interpreter, the native API and its hierarchy of interfaces provide mechanisms to interact with and utilize various components of a victimized system. Native API functions (such as NtCreateProcess) may be directed invoked via system calls / syscalls, but these features are also often exposed to user-mode applications via interfaces and libraries. For example, functions such as the Windows API CreateProcess() or GNU fork() will allow programs and scripts to start other processes. This may allow API callers to execute a binary, run a CLI command, load modules, etc. as thousands of similar API functions exist for various system operations. Higher level software frameworks, such as Microsoft .NET and macOS Cocoa, are also available to interact with native APIs. These frameworks typically provide language wrappers/abstractions to API functionalities and are designed for ease-of-use/portability of code. Adversaries may use assembly to directly or in-directly invoke syscalls in an attempt to subvert defensive sensors and detection signatures such as user mode API-hooks. Adversaries may also attempt to tamper with sensors and defensive tools associated with API monitoring, such as unhooking monitored functions via Disable or Modify Tools.
T1134.001 Access Token Manipulation: Token Impersonation/Theft
Adversaries may duplicate then impersonate another user's existing token to escalate privileges and bypass access controls. For example, an adversary can duplicate an existing token using `DuplicateToken` or `DuplicateTokenEx`. The token can then be used with `ImpersonateLoggedOnUser` to allow the calling thread to impersonate a logged on user's security context, or with `SetThreadToken` to assign the impersonated token to a thread. An adversary may perform Token Impersonation/Theft when they have a specific, existing process they want to assign the duplicated token to. For example, this may be useful for when the target user has a non-network logon session on the system. When an adversary would instead use a duplicated token to create a new process rather than attaching to an existing process, they can additionally Create Process with Token using `CreateProcessWithTokenW` or `CreateProcessAsUserW`. Token Impersonation/Theft is also distinct from Make and Impersonate Token in that it refers to duplicating an existing token, rather than creating a new one.
T1140 Deobfuscate/Decode Files or Information
Adversaries may use Obfuscated Files or Information to hide artifacts of an intrusion from analysis. They may require separate mechanisms to decode or deobfuscate that information depending on how they intend to use it. Methods for doing that include built-in functionality of malware or by using utilities present on the system. One such example is the use of certutil to decode a remote access tool portable executable file that has been hidden inside a certificate file. Another example is using the Windows copy /b command to reassemble binary fragments into a malicious payload. Sometimes a user's action may be required to open it for deobfuscation or decryption as part of User Execution. The user may also be required to input a password to open a password protected compressed/encrypted file that was provided by the adversary.
T1190 Exploit Public-Facing Application
Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network. The weakness in the system can be a software bug, a temporary glitch, or a misconfiguration. Exploited applications are often websites/web servers, but can also include databases (like SQL), standard services (like SMB or SSH), network device administration and management protocols (like SNMP and Smart Install), and any other system with Internet-accessible open sockets. Depending on the flaw being exploited this may also involve Exploitation for Defense Evasion or Exploitation for Client Execution. If an application is hosted on cloud-based infrastructure and/or is containerized, then exploiting it may lead to compromise of the underlying instance or container. This can allow an adversary a path to access the cloud or container APIs (e.g., via the Cloud Instance Metadata API), exploit container host access via Escape to Host, or take advantage of weak identity and access management policies. Adversaries may also exploit edge network infrastructure and related appliances, specifically targeting devices that do not support robust host-based defenses. For websites and databases, the OWASP top 10 and CWE top 25 highlight the most common web-based vulnerabilities.
T1518 Software Discovery
Adversaries may attempt to get a listing of software and software versions that are installed on a system or in a cloud environment. Adversaries may use the information from Software Discovery during automated discovery to shape follow-on behaviors, including whether or not the adversary fully infects the target and/or attempts specific actions. Such software may be deployed widely across the environment for configuration management or security reasons, such as Software Deployment Tools, and may allow adversaries broad access to infect devices or move laterally. Adversaries may attempt to enumerate software for a variety of reasons, such as figuring out what security measures are present or if the compromised system has a version of software that is vulnerable to Exploitation for Privilege Escalation.
T1609 Container Administration Command
Adversaries may abuse a container administration service to execute commands within a container. A container administration service such as the Docker daemon, the Kubernetes API server, or the kubelet may allow remote management of containers within an environment. In Docker, adversaries may specify an entrypoint during container deployment that executes a script or command, or they may use a command such as docker exec to execute a command within a running container. In Kubernetes, if an adversary has sufficient permissions, they may gain remote execution in a container in the cluster via interaction with the Kubernetes API server, the kubelet, or by running a command such as kubectl exec.
T1611 Escape to Host
Adversaries may break out of a container to gain access to the underlying host. This can allow an adversary access to other containerized resources from the host level or to the host itself. In principle, containerized resources should provide a clear separation of application functionality and be isolated from the host environment. There are multiple ways an adversary may escape to a host environment. Examples include creating a container configured to mount the host’s filesystem using the bind parameter, which allows the adversary to drop payloads and execute control utilities such as cron on the host; utilizing a privileged container to run commands or load a malicious kernel module on the underlying host; or abusing system calls such as `unshare` and `keyctl` to escalate privileges and steal secrets. Additionally, an adversary may be able to exploit a compromised container with a mounted container management socket, such as `docker.sock`, to break out of the container via a Container Administration Command. Adversaries may also escape via Exploitation for Privilege Escalation, such as exploiting vulnerabilities in global symbolic links in order to access the root directory of a host machine. Gaining access to the host may provide the adversary with the opportunity to achieve follow-on objectives, such as establishing persistence, moving laterally within the environment, accessing other containers running on the host, or setting up a command and control channel on the host.

List of groups using the malware :


id description

© 2022 The MITRE Corporation. This work is reproduced and distributed with the permission of The MITRE Corporation.