Tripwires

A subject uses files with canary tokens as a tripwire mechanism to detect the presence of security personnel or investigation activities within a compromised environment. This method involves strategically placing files embedded with special identifiers (canary tokens) that trigger alerts when accessed. For example:

The subject creates files containing canary tokens—unique identifiers that generate an alert when they are accessed, opened, or modified. These files can appear as regular documents, logs, configurations, or other items that might attract the attention of an investigator during a security response.

The subject strategically places these files in various locations within the environment:

• Endpoints: Files with canary tokens are stored in directories where digital forensics or malware analysis is likely to occur, such as system logs, user data directories, or registry entries.
• Cloud Storage: The files are uploaded to cloud storage buckets, virtual machines, or application databases where security teams might search for indicators of compromise.
• Network Shares: Shared drives and network locations where forensic investigators or security tools may perform scans.

Once in place, the canary token within each file serves as a silent tripwire. The token monitors for access and automatically triggers an alert if an action is detected:

• Access Detection: If a security tool, administrator, or investigator attempts to open, modify, or copy the file, the embedded canary token sends an alert to an external server controlled by the subject.
• Network Traffic: The token can initiate an outbound network request (e.g., HTTP, DNS) to a specified location, notifying the subject of the exact time and environment where the access occurred.
• Behavior Analysis: The subject might include multiple canary files, each with unique tokens, to identify the pattern of investigation, such as the sequence of directories accessed or specific file types of interest to the security team.

Upon receiving an alert from a triggered canary token, the subject can take immediate steps to evade detection:

• Alert the Subject: The canary token sends a covert signal to the subject's designated server or communication channel, notifying them of the potential investigation.
• Halt Malicious Activity: The subject can use this warning to suspend ongoing malicious actions, such as data exfiltration or command-and-control communications, to avoid further detection.
• Clean Up Evidence: Scripts can be triggered to delete or alter logs, remove incriminating files, or revert system configurations to their original state, complicating any forensic investigation.
• Feign Normalcy: The subject can restore or disguise compromised systems to appear as though nothing suspicious has occurred, minimizing signs of tampering.

By using files with canary tokens as tripwires, a subject can gain early warning of investigative actions and respond quickly to avoid exposure. This tactic allows them to outmaneuver standard security investigations by leveraging silent alerts that inform them of potential security team activity.

A subject installs custom software or malware on an endpoint, potentially disguising it as a legitimate process. This software includes tripwire logic to monitor the system for signs of security activity.

The tripwire software monitors various aspects of the endpoint to detect potential investigations:

• Security Tool Detection: It scans running processes and monitors new files or services for signatures of known security tools, such as antivirus programs, forensic tools, and Endpoint Detection and Response (EDR) systems.
• File and System Access: It tracks access to critical files or system directories (e.g., system logs, registry entries) commonly accessed during security investigations. Attempts to open or read sensitive files can trigger an alert.
• Network Traffic Analysis: The software analyzes network traffic to identify unusual patterns, including connections to Security Operations Centers (SOC) or the blocking of command-and-control servers by network security controls.
• User and System Behavior: It observes system behavior and monitors logs (such as event logs) that indicate an investigation is in progress, such as switching to an administrative account or modifying security settings (e.g., enabling disk encryption, changing firewall rules).

Upon detecting security activity, the tripwire can initiate various evasive responses:

• Alert the Subject: It covertly sends an alert to an external server controlled by the subject, using common system tools (e.g., curl, wget, or HTTP requests).
• Modify Endpoint Behavior: It can terminate malicious processes, erase evidence (e.g., logs, browser history, specific files), or restore system and network configurations to conceal signs of tampering.

The subject develops a custom API that monitors specific activities, network traffic, and system changes within the target environment. The API could monitor HTTP/HTTPS requests directed at sensitive endpoints, track modifications to security group settings (such as firewalls or access policies), and identify administrative actions like changes to user accounts, data access requests, or logging configurations.

This tripwire API is embedded within various parts of the environment:

• Cloud Services: It hooks into serverless functions, containers, or virtual machines to monitor access and activity.
• Applications: It integrates into custom-built web applications to observe access to certain URLs, paths, or endpoints.
• Infrastructure Services: It monitors cloud management APIs (e.g., AWS, Azure, Google Cloud) for unusual activities indicative of an investigation.

Once deployed, the tripwire API continuously monitors network traffic, API calls, and system changes for indicators of an investigation. It looks for:

• Known Security Tools: Scanning for network traffic signatures from common security tools (like Nessus or nmap) or patterns associated with incident response teams.
• Unusual Access: Detecting attempts from IP ranges linked to internal security teams or cloud provider security operations centers.
• System Changes: Watching for actions typical of an investigation, such as new logging mechanisms, alterations to IAM roles, or the activation of cloud monitoring services.

The API can use whitelists for expected IP addresses or user accounts, triggering alerts if unexpected access occurs.

Upon detecting activity, the API tripwire can take immediate evasive actions:

• Alert the Subject: It sends covert alerts to an external server controlled by the subject, through an HTTP request, encrypted email, or messaging platform.
• Suspend Malicious Activity: If integrated into a malicious workflow, the API can halt ongoing data exfiltration or malware processes.
• Clean Up Evidence: It triggers scripts to delete logs, clear files, or reset system configurations to hinder forensic analysis.
• Feign Normalcy: It restores access controls and system settings to their default state, masking any signs of unusual activity.