---
title: 'Event Correlation'
description: 'Real-time pattern-based multi-step attack detection using a sliding time window and 7 correlation patterns.'
icon: 'diagram-project'
---

The `EventCorrelator` implements real-time, pattern-based multi-step attack detection. Rather than evaluating events in isolation, it maintains a sliding window buffer and applies 7 pattern detectors to identify attack chains that span multiple events.

## Architecture

```
Events ──> [Sliding Window Buffer] ──> [Pattern Detectors] ──> CorrelationResult
                Max 1000 events              7 patterns
                5-minute window
```

The correlator runs inside the `DetectAgent` and produces `CorrelationPattern` objects that boost the confidence score in the `AnalyzeAgent`.

## Sliding Window Buffer

| Parameter       | Value                                                |
| --------------- | ---------------------------------------------------- |
| Maximum events  | 1,000                                                |
| Time window     | 5 minutes                                            |
| Eviction policy | Events older than 5 minutes are discarded            |
| Grouping        | Events are grouped by source IP for pattern matching |

## 7 Correlation Patterns

### 1. Brute Force Detection

| Field               | Value                                                        |
| ------------------- | ------------------------------------------------------------ |
| **MITRE ATT&CK**    | T1110                                                        |
| **Detection logic** | Authentication failures from the same source IP              |
| **Window**          | 60 seconds                                                   |
| **Threshold**       | 5 events                                                     |
| **Confidence**      | 60 base + 8 per additional event (max 100)                   |
| **Example**         | 15 failed SSH login attempts from 203.0.113.50 in 30 seconds |

### 2. Port Scan Detection

| Field               | Value                                                                          |
| ------------------- | ------------------------------------------------------------------------------ |
| **MITRE ATT&CK**    | T1046                                                                          |
| **Detection logic** | Connections to distinct destination ports from the same IP                     |
| **Window**          | 60 seconds                                                                     |
| **Threshold**       | 10 distinct ports                                                              |
| **Confidence**      | 65 base + 3 per additional port (max 100)                                      |
| **Example**         | Single IP probing ports 22, 80, 443, 3306, 5432, 6379, 8080, 8443, 9200, 27017 |

### 3. Lateral Movement

| Field               | Value                                                                   |
| ------------------- | ----------------------------------------------------------------------- |
| **MITRE ATT&CK**    | T1021                                                                   |
| **Detection logic** | Connections to distinct internal (RFC 1918) IP addresses                |
| **Window**          | 5 minutes                                                               |
| **Threshold**       | 3 distinct internal IPs                                                 |
| **Confidence**      | 55 base + 10 per additional IP (max 100)                                |
| **Example**         | Compromised host connecting to 192.168.1.10, 192.168.1.20, 192.168.1.30 |

### 4. Data Exfiltration

| Field               | Value                                          |
| ------------------- | ---------------------------------------------- |
| **MITRE ATT&CK**    | T1041                                          |
| **Detection logic** | Large outbound data transfer to an external IP |
| **Window**          | Single event evaluation                        |
| **Threshold**       | 10 MB                                          |
| **Confidence**      | 50 base + 15 per additional 10 MB (max 100)    |
| **Example**         | 45 MB upload to an external IP via curl        |

### 5. Backdoor Installation

| Field               | Value                                                                                 |
| ------------------- | ------------------------------------------------------------------------------------- |
| **MITRE ATT&CK**    | T1059                                                                                 |
| **Detection logic** | Combination of file write + process creation + outbound network connection            |
| **Window**          | 5 minutes                                                                             |
| **Threshold**       | All 3 event types present                                                             |
| **Confidence**      | 55 base, increases with additional correlated events (max 100)                        |
| **Example**         | File written to `/tmp/payload`, new process spawned, outbound connection to C2 server |

### 6. Privilege Escalation

| Field               | Value                                                        |
| ------------------- | ------------------------------------------------------------ |
| **MITRE ATT&CK**    | T1548                                                        |
| **Detection logic** | setuid/setgid/sudo/pkexec events                             |
| **Window**          | 5 minutes                                                    |
| **Threshold**       | 1 or more events                                             |
| **Confidence**      | 50 base + 15 per additional event (max 100)                  |
| **Example**         | Multiple `sudo` invocations followed by `setuid` system call |

### 7. Severity Escalation

| Field               | Value                                                              |
| ------------------- | ------------------------------------------------------------------ |
| **MITRE ATT&CK**    | -- (compound pattern)                                              |
| **Detection logic** | Accumulation of low or medium severity events from the same source |
| **Window**          | 5 minutes                                                          |
| **Threshold**       | 3 events at the same severity level                                |
| **Confidence**      | 40 base + 10 per additional event (max 100)                        |
| **Promotion rules** | 3+ low events promote to medium; 3+ medium events promote to high  |

## Correlation Result

When a pattern matches, the correlator produces a `CorrelationResult` containing:

```typescript
interface CorrelationResult {
  pattern: string; // e.g., "brute_force"
  mitreId: string; // e.g., "T1110"
  confidence: number; // 0-100
  relatedEvents: string[]; // event IDs in the chain
  sourceIp: string; // common source IP
  description: string; // human-readable summary
}
```

The `AnalyzeAgent` applies a correlation boost of +5 per correlated event, up to a maximum of +25 added to the final confidence score.

<Warning>
  The correlation engine operates in memory. Restarting the Guard engine clears the sliding window
  buffer. Persistent cross-session correlation is available when a Manager server is connected.
</Warning>
