PowerShell Special Characters Obfuscation Data Obfuscation

PowerShell scripts can be obfuscated using methods that encode commands exclusively with special characters. This technique aims to complicate analysis and potentially evade detection mechanisms.

Attackers frequently employ these tactics to hide the true functionalities of the script, making the analysis more challenging.

Impair Defenses: Impair Command History Logging Defense Evasion [Mitre]

Adversaries may impair command history logging to hide commands they run on a compromised system. Various command interpreters keep track of the commands users type in their terminal so that users can retrace what they've done.

Impair Defenses: Indicator Blocking Defense Evasion [Mitre]

An adversary may attempt to block indicators or events typically captured by sensors from being gathered and analyzed. This could include maliciously redirecting or even disabling host-based sensors, such as Event Tracing for Windows (ETW), by tampering settings that control the collection and flow of event telemetry. These settings may be stored on the system in configuration files and/or in …

Indicator Removal: Clear Command History Defense Evasion [Mitre]

In addition to clearing system logs, an adversary may clear the command history of a compromised account to conceal the actions undertaken during an intrusion. Various command interpreters keep track of the commands users type in their terminal so that users can retrace what they've done.

On Windows hosts, PowerShell has two different command history providers: the built-in history …

Virtualization/Sandbox Evasion: System Checks Defense Evasion [Mitre]

Adversaries may employ various system checks to detect and avoid virtualization and analysis environments. This may include changing behaviors based on the results of checks for the presence of artifacts indicative of a virtual machine environment (VME) or sandbox. If the adversary detects a VME, they may alter their malware to disengage from the victim or conceal the core functions …

Process Camouflage, Masquerading Process Manipulating

Masquerading is a technique used by malware to evade detection by disguising itself as a legitimate file. This is typically achieved by renaming the malicious file to match the name of a commonly found and trusted file, such as svchost.exe, and placing it in a legitimate folder.

Masquerading can occur when the name or location of an executable, …

Access Token Manipulation: Parent PID Spoofing Process Manipulating Defense Evasion [Mitre]

Adversaries may spoof the parent process identifier (PPID) of a new process to evade process-monitoring defenses or to elevate privileges. New processes are typically spawned directly from their parent, or calling, process unless explicitly specified.

One way of explicitly assigning the PPID of a new process is via the CreateProcess API call, which supports a parameter that defines the …

Windows File and Directory Permissions Modification Defense Evasion [Mitre]

Adversaries may modify file or directory permissions/attributes to evade access control lists (ACLs) and access protected files. File and directory permissions are commonly managed by ACLs configured by the file or directory owner, or users with the appropriate permissions. File and directory ACL implementations vary by platform, but generally explicitly designate which users or groups can perform which actions (read, …

Hide Artifacts: Hidden Window Defense Evasion [Mitre]

Adversaries may use hidden windows to conceal malicious activity from the plain sight of users. In some cases, windows that would typically be displayed when an application carries out an operation can be hidden. This may be utilized by system administrators to avoid disrupting user work environments when carrying out administrative tasks.

On Windows, there are a variety of …

Hide Artifacts: Email Hiding Rules Defense Evasion [Mitre]

Adversaries may use email rules to hide inbound emails in a compromised user's mailbox. Many email clients allow users to create inbox rules for various email functions, including moving emails to other folders, marking emails as read, or deleting emails. Rules may be created or modified within email clients or through external features such as the New-InboxRule or Set-InboxRule PowerShell …

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