Adversaries may create or modify Windows services to repeatedly execute malicious payloads as part of persistence. When Windows boots up, it starts programs or applications called services that perform background system functions.(Citation: TechNet Services) Windows service configuration information, including the file path to the service's executable or recovery programs/commands, is stored in the Windows Registry.
Adversaries may install a new service or modify an existing service to execute at startup in order to persist on a system. Service configurations can be set or modified using system utilities (such as sc.exe), by directly modifying the Registry, or by interacting directly with the Windows API.
Adversaries may also use services to install and execute malicious drivers. For example, after dropping a driver file (ex: .sys) to disk, the payload can be loaded and registered via Native API functions such as CreateServiceW() (or manually via functions such as ZwLoadDriver() and ZwSetValueKey()), by creating the required service Registry values (i.e. Modify Registry), or by using command-line utilities such as PnPUtil.exe.(Citation: Symantec W.32 Stuxnet Dossier)(Citation: Crowdstrike DriveSlayer February 2022)(Citation: Unit42 AcidBox June 2020) Adversaries may leverage these drivers as Rootkits to hide the presence of malicious activity on a system. Adversaries may also load a signed yet vulnerable driver onto a compromised machine (known as "Bring Your Own Vulnerable Driver" (BYOVD)) as part of Exploitation for Privilege Escalation.(Citation: ESET InvisiMole June 2020)(Citation: Unit42 AcidBox June 2020)
Services may be created with administrator privileges but are executed under SYSTEM privileges, so an adversary may also use a service to escalate privileges. Adversaries may also directly start services through Service Execution.
To make detection analysis more challenging, malicious services may also incorporate Masquerade Task or Service (ex: using a service and/or payload name related to a legitimate OS or benign software component). Adversaries may also create ‘hidden’ services (i.e., Hide Artifacts), for example by using the sc sdset command to set service permissions via the Service Descriptor Definition Language (SDDL). This may hide a Windows service from the view of standard service enumeration methods such as Get-Service, sc query, and services.exe.(Citation: SANS 1)(Citation: SANS 2)
Detection of Windows Service Creation or Modification
Behavior Prevention on Endpoint: Behavior Prevention on Endpoint refers to the use of technologies and strategies to detect and block potentially malicious activities by analyzing the behavior of processes, files, API calls, and other endpoint events. Rather than relying solely on known signatures, this approach leverages heuristics, machine learning, and real-time monitoring to identify anomalous patterns indicative of an attack. This mitigation can be implemented through the following measures:
Suspicious Process Behavior:
Unauthorized File Access:
Abnormal API Calls:
OpenProcess and WriteProcessMemory and terminates the offending process.Exploit Prevention:
Operating System Configuration: Operating System Configuration involves adjusting system settings and hardening the default configurations of an operating system (OS) to mitigate adversary exploitation and prevent abuse of system functionality. Proper OS configurations address security vulnerabilities, limit attack surfaces, and ensure robust defense against a wide range of techniques. This mitigation can be implemented through the following measures:
Disable Unused Features:
Enforce OS-level Protections:
Secure Access Settings:
File System Hardening:
Secure Remote Access:
Harden Boot Configurations:
Regular Audits:
Tools for Implementation
Windows:
Linux/macOS:
Cross-Platform:
Audit: Auditing is the process of recording activity and systematically reviewing and analyzing the activity and system configurations. The primary purpose of auditing is to detect anomalies and identify potential threats or weaknesses in the environment. Proper auditing configurations can also help to meet compliance requirements. The process of auditing encompasses regular analysis of user behaviors and system logs in support of proactive security measures.
Auditing is applicable to all systems used within an organization, from the front door of a building to accessing a file on a fileserver. It is considered more critical for regulated industries such as, healthcare, finance and government where compliance requirements demand stringent tracking of user and system activates.This mitigation can be implemented through the following measures:
System Audit:
Permission Audits:
Software Audits:
Configuration Audits:
Network Audits:
Code Signing: Code Signing is a security process that ensures the authenticity and integrity of software by digitally signing executables, scripts, and other code artifacts. It prevents untrusted or malicious code from executing by verifying the digital signatures against trusted sources. Code signing protects against tampering, impersonation, and distribution of unauthorized or malicious software, forming a critical defense against supply chain and software exploitation attacks. This mitigation can be implemented through the following measures:
Enforce Signed Code Execution:
Vendor-Signed Driver Enforcement:
Certificate Revocation Management:
Third-Party Software Verification:
Script Integrity in CI/CD Pipelines:
Key Components of Code Signing
User Account Management: User Account Management involves implementing and enforcing policies for the lifecycle of user accounts, including creation, modification, and deactivation. Proper account management reduces the attack surface by limiting unauthorized access, managing account privileges, and ensuring accounts are used according to organizational policies. This mitigation can be implemented through the following measures:
Enforcing the Principle of Least Privilege
Implementing Strong Password Policies
Managing Dormant and Orphaned Accounts
Account Lockout Policies
Multi-Factor Authentication (MFA) for High-Risk Accounts
Restricting Interactive Logins
Tools for Implementation
Built-in Tools:
Identity and Access Management (IAM) Tools:
Privileged Account Management (PAM):