Security Event Logs

This guide goes into the details of Security Event Logging in Sourcegraph

Note: You can find more information about our audit logs setup here

Here is a guide on how to add logging to Sourcegraph backend

What are Security Event Logs

The purpose of Security Event Logs is to allow security specialists to be able to trace the steps of a user or an admin across the application.
Getting a full picture of how a user moves through the application, in a single location, is crucial for many reasons.
When a user takes an action on sensitive information within the application, this should be logged to make sure it can be retraced to the user and time.
In Sourcegraph application, these sensitive actions are logged as "security event" with relevant information included in the log output.
These logs can be enabled/disabled as well as the location can be set via the site config settings
Previously, we were logging a very selective set of actions. However, through various analyses, it was determined that there were some gaps in creating a full picture.
- New event types are constantly being added to fill these gaps.

How to log a security event

All the logging for security event is done through our security_event_log.go functions

Previously, events were created within the function where the action was taking place and then pushed to the logging location like this:

GO
event := &SecurityEvent{
  	Name:            SecurityEventNameAccessGranted,
  	URL:             "",
  	UserID:          uint32(a.UID),
  	AnonymousUserID: "",
  	Argument:        arg,
  	Source:          "BACKEND",
  	Timestamp:       time.Now(),
  }
 
  db.SecurityEventLogs().LogEvent(ctx, event)

With a recent change to streamline the process, to log an event, the LogSecurityEvent function can be invoked which takes care of marshaling the arguments and creating the SecurityEvent.
This function takes following information to create a log event
- Context contains information on the acting user
- SecurityEventName which is predefined here
- URL if available
- userID of the user that the action is applied towards
- anonymousUserID for unauthenticated users
- source of the log
- arguments relevant to the action being logged

Example of using the function to logan event

GO
db.SecurityEventLogs().LogSecurityEvent(ctx, database.SecurityEventNameEmailAdded, r.URL.Path, uint32(actr.UID), "", "BACKEND", email)

The function sends the log event it creates to be pushed to the right location based on the site-config settings
The function also checks to make sure that marshaling the arguments does not cause as error

How to find security events in logs

Security events are logged with all the relevant information associated with the actions
Depending on the location of the log destination set in the site config, the event log can be either found in the application log output or in the database or both.

A sample output of a logged event from application logs would look similar to this:

JSON
{
...
{
  "message": "EmailAdded (sampling immunity token: 12345-222-3333-5454-9w08fs0s9d8f)",
  "Caller": "audit/audit.go:57",
  "Attributes": {
    "audit": {
      "actor": {
        "X-Forwarded-For": "127.0.0.1",
        "userAgent": "Mozilla/5.0 (Windows NT 10.0; Win64; x64) ",
        "ip": "100.211.3.155",
        "actorUID": "123245"
      },
      "entity": "security events",
      "auditId": "12345-222-3333-5454-9w08fs0s9d8f",
      "action": "EmailAdded"
    },
    "event": {
      "URL": "",
      "argument": "\"new@sourcegraph.com\"",
      "AnonymousUserID": "",
      "UserID": 223955,
      "source": "12345",
      "timestamp": "2023-12-21 02:41:08.649603776 +0000 UTC",
      "version": "255367_2023-12-20_5.2-a3143120c41e"
    }
  },
  "Function": "github.com/sourcegraph/sourcegraph/internal/audit.Log",
  "InstrumentationScope": "frontend.SecurityEvents",
  "timestampNanos": 1703126468649641000,
  "Resource": {
    "service.instance.id": "sourcegraph-frontend-769bdbdd77-p2f8j",
    "service.name": "frontend",
    "service.version": "255367_2023-12-20_5.2-a3143120c41e"
  }
}
...
}

Entity field can be used to filter on all security events.
Action field will provide information on the event and can be correlated with the action taken, in this case EmailAdded
The actorUID can be used to filter out events from a particular user
UserID can be used to filter out actions taken on a particular user's information

FAQ

What events are currently being logged as security events?

These are the events that are currently being logged.

What if I don't want these events to be logged?

To turn off all security event logs, you can set the variable in the site config

How can I correlate the actorID or userID to a user in the application?

Currently UIDs are available in the log output but it’s not mapped into a full Sourcegraph user. You can, however, obtain the user details by following these steps:
1. Grab the ID from the audit log
2. Base64 encode the ID with a "User:" prefix. For example, for Actor with ID 71 use User:71, which encodes to VXNlcjo3MQ==
3. Navigate to Site Admin -> API Console and run the query below
4. Find the corresponding user by searching the query results for the encoded ID from above

GraphQL query:

SHELL
{
  users {
    nodes {
      id
      username
    }
  }
}

How can I investigate all actions taken on a user?

The audit.event node has the ID of the user the action was taken on (UserID). Logs can be filtered on this field to gather all logged actions taken on this user's information.

How can I investigate all actions taken by a user?

The audit.actor node has the ID of the user the action was taken by (actorUID). Logs can be filtered on this field to gather all logged actions taken by this user.