Canary Tokens

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.