Responder Tamper Detection

Overview

Tamper Detection is a security feature that protects the integrity and continuous operation of AIR Responders. When enabled, the Responder watchdog actively monitors the agent for interference, modification, or attempts to disable it. If suspicious activity is detected, the watchdog immediately reports the event to the AIR console.

This feature is critical in high‑security environments where maintaining asset visibility and control is essential.

How Tamper Detection Works

Tamper Detection is handled by the agent-watchdog component. When a tamper condition is detected, the watchdog sends an HTTP POST request to:

{ConsoleAddress}/api/endpoints/{EndpointID}/event-log

Important behavior:

• The watchdog does not use the current agent configuration for reporting.
• It uses a backup configuration saved during installation.
• This ensures reporting still succeeds if the current config is missing or maliciously modified.

If reporting fails:

• Events are queued on disk.
• Retries use exponential backoff.
• Maximum retry duration is approximately 1 day.
• Reporting supports Relay and proxy configurations if configured.

Where Tamper Events Appear

Tamper Detection events are posted to the AIR console event log endpoint and are visible in Activity > Audit Logs. You can filter by:

• EventClass = TamperDetectionEvent
• Category = System
• Source = agent-watchdog

See Console Audit Logs for details on access, filtering, and retention.

Tamper Detection Event Types

There are three Tamper Detection event types. All share the following common properties:

EventClass = TamperDetectionEvent
Category   = System
Severity   = S
Source     = agent-watchdog

1) agent-not-found

Title format

Tamper detected (agent-not-found) on asset {AssetName}

Trigger condition

The Responder executable file no longer exists on disk.

Detection logic

The watchdog checks the agent binary path using:

os.Lstat()

If the check returns fs.ErrNotExist, the event is triggered.

Typical scenarios

• Responder was uninstalled.
• The agent executable was manually deleted.
• The installation directory was removed.

Meaning

The Responder binary is missing from the system.

2) agent-suspended

Title format

Tamper detected (agent-suspended) on asset {AssetName}

Trigger condition

The Responder binary exists on disk, but the agent process is not running.

Detection logic

After confirming the binary exists, the watchdog checks whether the agent holds its single‑instance lock.

Platform-specific behavior

• Windows: checks for named mutex Global\AIRAgentRunning
• Unix-based systems: checks file lock using flock on:

/var/run/Binalyze.AIR.Agent.pid

If the lock is not held, the agent is considered suspended.

Typical scenarios

• Responder service manually stopped using sc stop, systemctl stop, or launchctl unload
• Agent process crashed and did not restart
• Service disabled

Meaning

The Responder binary exists but the service is not running.

3) agent-config-changed

Title format

Tamper detected (agent-config-changed) on asset {AssetName}

Trigger condition

The current agent configuration differs from the watchdog’s backup configuration.

Detection logic

When installed, the watchdog stores a backup copy of the agent configuration. Each time it runs, it compares the current configuration with the backup. If differences are detected in monitored fields, the event is triggered.

Monitored configuration fields

Only the following fields are included in the tamper comparison:

Field	Description
ConsoleAddress	AIR console URL
RegisteredTo	Registration URL
SecurityToken	Authentication token
EndpointID	Unique asset ID
DebugLogging	Debug logging flag
CACert	TLS CA certificate
ProxyEnabled	Proxy enabled flag
OrganizationID	Organization identifier

Excluded from comparison

• RelayURL

Typical scenarios

• Console address modified to redirect to another server
• Security token changed
• Asset ID altered
• CA certificate modified
• Debug logging enabled/disabled outside normal console operations

Meaning

The Responder configuration has been modified outside expected console‑controlled operations.

Additional Watchdog Behavior

Update handling

If the watchdog detects a .update trigger directory, it skips all checks to avoid false positives during updates. If the directory is older than 10 minutes, it is considered stale, removed, and normal checks resume.

Uninstall handling

If a .uninstall trigger directory exists, the watchdog treats the removal as intentional. Process checks are skipped.

Example Event Structure

Example event fields:

• Title = Tamper detected (agent-not-found) on asset 110-Win2025-Responder
• EventClass = TamperDetectionEvent
• Category = System
• Severity = S
• HeaderEventSource = System
• EventDate = 2026.02.11 15:12:47
• ID = 7f370182-6a09-4b2f-befd-4a56fcfe05ea
• Time = 2026-02-11T16:51:55.3001356+04:30
• Type = agent-not-found
• Source = agent-watchdog
• Version = 2.85.0
• Platform = windows
• EventLogId = 2050eab7-3278-4085-b84c-38ca2759ee25
• EventSource = System
• AssetName = 110-Win2025-Responder

This is how a tamper event appears in the AIR console. To view it, go to Activity → Audit Logs and filter for TamperDetectionEvent.

Responder Tamper Detection: Example of agent-not-found event

Summary Table

Event Type	Trigger Condition	Meaning
agent-not-found	Agent executable missing	Responder removed or binary deleted
agent-suspended	Binary exists but process not running	Service stopped, disabled, or crashed
agent-config-changed	Configuration differs from backup	Configuration modified outside console

Why Tamper Detection Is Critical

Tamper Detection ensures:

• Early detection of malicious interference
• Continuous monitoring of asset integrity
• Protection against unauthorized configuration changes
• Reliable alerting even if the agent is modified or removed