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Suspicious command execution or file injection remediation

Entities: User, Process name Log type: Windows Server

In this page

Playbook Description

This playbook investigates file injection threats by analyzing process behavior, checking file reputation, and evaluating user activity. If a threat is confirmed, it initiates remediation steps including terminating malicious processes, quarantining files, removing persistence mechanisms, and notifying the security teams.

MITRE ATT&CK mapping

Tactics Techniques Sub-techniques
Lateral Movement(TA0008) Remote Service Session Hijacking(T1563) RDP Hijacking(T1563.002)

MITRE D3FEND mapping

Tactics Techniques Sub-techniques
Harden(D3-Harden) Access Mediation(D3-AMED)  

Playbook input type

Alert

Prerequisites

  • Log360 Cloud - Connection to execute PowerShell scripts on the target Windows host for investigation and remediation actions.
  • Privileges - Admin privileges on the target host are required.

Dependencies

Utility functions:

  • utility_convertTimeToUTC
  • utility_getRequiredTime
  • utility_convertToString
  • utility_setKeyValue
  • windows_decodeCommand
  • windows_commandLineAnalysis
  • windows_detectMaliciousProcessChain
  • windows_detectMaliciousUser
  • utility_sendMail

Scripts

Script Name Description Arguments
FetchUserDetails.ps1 Fetches detailed user information (password expiry, group memberships, admin status) for both domain (AD) and local users Name
EnableASARuleForMaliciousDownloadViaWeb.ps1 Enables the ASR rule to prevent malicious web downloads (Rule ID: BE9BA2D9-53EA-4CDC-84E5-9B1EEEE46550) -
CheckAndRemoveFiles.ps1 Checks for suspicious or malicious files in specified paths and removes them if found FolderPath, Extensions
TerminateSession.ps1 Logs off one or more user sessions using logoff , with optional RDP-only filtering by remote IP UserNames
FetchPersistenceEntries.ps1 Scans for persistence mechanisms including scheduled tasks, registry Run/RunOnce keys, startup folder entries, and services to identify potential malicious persistence -
StopProcess.ps1 Stops processes by PID or file path. Supports hex PIDs and comma-separated inputs. Skips protected PowerShell executables. ProcessIdentifiers
FetchAndRemoveProcess.ps1 Scans temporary directories for suspicious script files (.ps1, .bat, .vbs) containing credential-related keywords, kills any processes running those scripts, and deletes the files AdditionalKeywords
BlockURLTraffic.ps1 Blocks traffic to a given URL by resolving its domain to IPaddresses, creating inbound and outbound Windows Firewall block rules (via New-NetFirewallRule ) for each resolved IP, and flushing the DNS cache. Url
QuarantineFiles.ps1 Moves one or more files to a quarantine directory ( %USERPROFILE%\Forensic_Quarantine ), strips inherited permissions via .NET ACL API, and grants read-only access to Administrators. Skips protected PowerShell executables. FilePaths

Sub playbooks

  • Log360 Cloud - Create or update incident
  • Windows - File enrichment
  • VirusTotal - URL reputation check

Execution workflow

Investigation:

  • Decodes the encoded command.
  • Fetches the user details.
  • Detects the malicious user.
  • Checks if no decoded command exists.
  • Passes command line input.
  • Analyzes the command line for suspicious patterns, URLs, or file paths.
  • Checks whether URL exists.
  • Passes URL reputation input.
  • Executes the "VirusTotal - URL reputation check" sub-playbook.
  • Checks whether file exists.
  • Executes the "Windows - File enrichment" sub-playbook.
  • Passes command analysis results.
  • Fetches the process tree execution.
  • Detects the malicious process chain.
  • Checks if any user alerts exists.

Decision logic:

  • Proceeds to remediation based on the following conditions:
    • The file or process reputation indicates high risk.
    • Malicious IPaddresses are identified.
    • The user is flagged as malicious based on behavior analysis.
    • A malicious execution flow was detected in the process tree.
    • Related investigation findings are present.
  • If no malicious indicators are confirmed, the playbook ends with no further actions.

Remediation:

  • Terminates the user session.
  • Checks whether colorcpl attack exists.
  • Checks and removes loaded malicious files.
  • Passes colorcpl file results.
  • Terminates the process execution.
  • Terminates the parent process.
  • Fetches and removes malicious processes.
  • Checks whether URL is malicious.
  • Blocks the malicious URL.
  • Checks whether malicious file is found.
  • Quarantines the files.
  • Blocks the malicious downloads.
  • Checks and removes persistence tasks.
  • Checks if any remediation failed.
  • Builds the notification email with remediation details and findings.
  • Sends a notification email regarding the actions taken and required next steps.
Execution Workflow
Figure: Execution workflow of the playbook

Post execution procedure

  • Review the quarantined files and blocked URLs for threat intelligence extraction.
  • Investigate whether the inject file payload was executed before remediation.
  • Check for any additional encoded command execution attempts by user.
  • Review persistence mechanisms across the organization for similar attack patterns.
  • Consider performing a full endpoint scan on the affected host and connected systems.