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533x 533x 533x 533x 533x 533x 533x 533x 533x 533x 533x 533x 533x 533x 533x | "use strict";
/**
* OCSF representation of security audit records.
*
* Every security audit record is an Open Cybersecurity Schema Framework
* ({@link OCSF_VERSION}) event: one JSON object per line, in one of six
* classes chosen by the oag-mcp event name (kept in `metadata.event_code`):
*
* | Class | Used for |
* | --- | --- |
* | Authentication (3002) | MCP caller authentication, upstream OAuth tokens |
* | API Activity (6003) | the `execute` tool call and each SDK operation's authorisation |
* | HTTP Activity (4002) | denied upstream destinations and redirects, rejected HTTP requests |
* | Process Activity (1007) | the Deno sandbox process: limits, denied capabilities, termination |
* | Application Lifecycle (6002) | security configuration applied, or start-up refused |
* | Detection Finding (2004) | forged bridge messages from agent code |
*
* Profiles used: Date/Time (`time_dt`), Security Control (allow and deny
* decisions), Host (`actor` where the class does not define it) and AI
* Operation (`message_context`: the MCP tool call and session).
*
* Call sites log camelCase fields; {@link toOcsfEvent} places the ones OCSF
* defines in their OCSF attribute and keeps the rest under `unmapped`.
*
* @module logging/ocsf
*/
import crypto from "node:crypto";
import net from "node:net";
import os from "node:os";
/** OCSF schema version followed. */
export const OCSF_VERSION = "1.9.0";
/** OCSF event classes used by oag-mcp, with the activities they use. */
const CLASSES = {
authentication: {
uid: 3002,
name: "Authentication",
category_uid: 3,
category_name: "Identity & Access Management",
activities: { 1: "Logon" },
},
api_activity: {
uid: 6003,
name: "API Activity",
category_uid: 6,
category_name: "Application Activity",
activities: { 1: "Create", 2: "Read", 3: "Update", 4: "Delete" },
},
http_activity: {
uid: 4002,
name: "HTTP Activity",
category_uid: 4,
category_name: "Network Activity",
activities: {
1: "Connect",
2: "Delete",
3: "Get",
4: "Head",
5: "Options",
6: "Post",
7: "Put",
8: "Trace",
9: "Patch",
},
},
process_activity: {
uid: 1007,
name: "Process Activity",
category_uid: 1,
category_name: "System Activity",
activities: { 2: "Terminate" },
},
application_lifecycle: {
uid: 6002,
name: "Application Lifecycle",
category_uid: 6,
category_name: "Application Activity",
activities: { 3: "Start" },
},
detection_finding: {
uid: 2004,
name: "Detection Finding",
category_uid: 2,
category_name: "Findings",
activities: { 1: "Create" },
},
} satisfies Record<
string,
{
uid: number;
name: string;
category_uid: number;
category_name: string;
activities: Record<number, string>;
}
>;
type OcsfClass = keyof typeof CLASSES;
/** OCSF `activity_id` 99 (Other): the activity is named by `activity_name`. */
const OTHER = 99;
/** API Activity's activity for each HTTP method. */
const API_ACTIVITY: Readonly<Record<string, number>> = {
POST: 1,
GET: 2,
HEAD: 2,
OPTIONS: 2,
PUT: 3,
PATCH: 3,
DELETE: 4,
};
/** HTTP Activity's activity for each HTTP method. */
const HTTP_ACTIVITY: Readonly<Record<string, number>> = {
CONNECT: 1,
DELETE: 2,
GET: 3,
HEAD: 4,
OPTIONS: 5,
POST: 6,
PUT: 7,
TRACE: 8,
PATCH: 9,
};
/** How an oag-mcp event maps to an OCSF class and activity. */
interface EventSpec {
cls: OcsfClass;
/** Activity id, or a source-specific name for activity 99 (Other). */
activity: number | string;
/** `status_id` regardless of the logged outcome. */
statusId?: 1 | 2;
/** `severity_id` regardless of the logged level. */
severityId?: number;
}
type Fields = Record<string, unknown>;
/**
* API Activity, with the activity of the SDK operation's HTTP method.
*
* @private
*/
function _api(f: Fields): EventSpec {
const method = String(f.httpMethod ?? "").toUpperCase();
return { cls: "api_activity", activity: API_ACTIVITY[method] ?? "Call" };
}
/**
* HTTP Activity, with the activity of the request's HTTP method.
*
* @private
*/
function _http(f: Fields): EventSpec {
const method = String(f.httpMethod ?? "").toUpperCase();
return {
cls: "http_activity",
activity: HTTP_ACTIVITY[method] ?? (method || "Request"),
};
}
const CONFIGURE: EventSpec = {
cls: "application_lifecycle",
activity: "Configure",
};
const START: EventSpec = { cls: "application_lifecycle", activity: 3 };
const LOGON: EventSpec = { cls: "authentication", activity: 1 };
const EXECUTE: EventSpec = { cls: "api_activity", activity: "Execute" };
const TERMINATE: EventSpec = {
cls: "process_activity",
activity: 2,
statusId: 1,
};
/**
* Every security audit event oag-mcp records, and its OCSF class and
* activity. Logging an event name not listed here is a compile-time error.
*/
const EVENTS = {
"authentication.mode_configured": () => CONFIGURE,
"authentication.succeeded": () => LOGON,
"authentication.failed": () => LOGON,
"authentication.token_in_url_rejected": () => LOGON,
"upstream.token.issue": () => ({
cls: "authentication",
activity: "Token Issue",
}),
"upstream.token.issue_failed": () => ({
cls: "authentication",
activity: "Token Issue",
}),
"upstream.token.refresh": () => ({
cls: "authentication",
activity: "Token Refresh",
}),
"upstream.token.refresh_failed": () => ({
cls: "authentication",
activity: "Token Refresh",
}),
"upstream.token.invalidated": () => ({
cls: "authentication",
activity: "Token Invalidate",
}),
"authorization.policy_loaded": () => CONFIGURE,
"authorization.allowed": _api,
"authorization.denied": _api,
"credential.provider.configured": () => CONFIGURE,
"credential.config_invalid": () => START,
"credential.lookup_failed": _api,
"execution.policy.applied": () => CONFIGURE,
"execution.requested": () => EXECUTE,
"execution.import_denied": () => EXECUTE,
"execution.resource_limit": (f) =>
f.operation !== undefined
? _api(f)
: f.pid !== undefined
? { cls: "process_activity", activity: "Limit" }
: EXECUTE,
"execution.capability_denied": () => ({
cls: "process_activity",
activity: "Capability Request",
}),
"execution.timeout": () => TERMINATE,
"executor.terminated": () => TERMINATE,
"execution.boundary_violation": () => ({
cls: "detection_finding",
activity: 1,
statusId: 1, // New
severityId: 3,
}),
"network.destination_denied": _http,
"network.redirect_denied": _http,
"transport.host_rejected": _http,
"transport.origin_rejected": _http,
"security.config_invalid": () => START,
"security.unauthenticated_nonloopback_refused": () => START,
} satisfies Record<string, (f: Fields) => EventSpec>;
/** A security audit event name. */
export type AuditEvent = keyof typeof EVENTS;
/** Every security audit event name, in catalogue order. */
export const AUDIT_EVENTS = Object.keys(EVENTS) as AuditEvent[];
/** Outcome of a security audit event, as logged by call sites. */
export type AuditOutcome =
"success" | "failure" | "allowed" | "denied" | "accepted" | "terminated";
/** Severity of a security audit event, as logged by call sites. */
export type AuditLevel = "info" | "warn" | "error";
/** `severity_id` for each logged level. */
const SEVERITY_ID: Readonly<Record<AuditLevel, number>> = {
info: 1,
warn: 2,
error: 4,
};
const SEVERITY_NAMES: Readonly<Record<number, string>> = {
1: "Informational",
2: "Low",
3: "Medium",
4: "High",
};
const STATUS_NAMES: Readonly<Record<number, string>> = {
1: "Success",
2: "Failure",
};
/** `auth_protocol_id` and `auth_protocol` for an MCP authentication mode. */
const AUTH_PROTOCOL: Readonly<Record<string, [number, string]>> = {
oauth: [6, "OAUTH 2.0"],
"static-bearer": [99, "Bearer Token"],
"stdio-process-boundary": [99, "Process Boundary"],
none: [99, "None"],
};
/** Identity of the oag-mcp process recording the events. */
export interface OcsfProduct {
/** Package name. */
name: string;
/** Package version. */
version: string;
/** Vendor (package author). */
vendorName?: string;
/** Server instance identifier. */
instanceId: string;
}
/**
* Reads event fields, remembering which were placed in an OCSF attribute so
* that the rest can be kept under `unmapped`.
*
* @private
*/
class FieldReader {
private readonly used = new Set<string>();
constructor(private readonly fields: Fields) {}
/** A field's value, marking it as placed. */
take(key: string): unknown {
this.used.add(key);
return this.fields[key];
}
/** A string field, marking it as placed. */
str(key: string): string | undefined {
const v = this.take(key);
return typeof v === "string" ? v : undefined;
}
/** A number field, marking it as placed. */
num(key: string): number | undefined {
const v = this.take(key);
return typeof v === "number" ? v : undefined;
}
/** Whether a field is present, without placing it. */
has(key: string): boolean {
return this.fields[key] !== undefined;
}
/** The fields not placed in any OCSF attribute. */
rest(): Fields {
const out: Fields = {};
for (const [k, v] of Object.entries(this.fields)) {
if (v !== undefined && !this.used.has(k)) {
out[k] = v;
}
}
return out;
}
}
/**
* An endpoint for a URL origin, by IP address or hostname.
*
* @private
*/
function _origin(origin: string): Fields {
try {
const url = new URL(origin);
const host = url.hostname.replace(/^\[|\]$/g, "");
const port = url.port
? Number(url.port)
: url.protocol === "https:"
? 443
: 80;
return net.isIP(host) ? { ip: host, port } : { hostname: host, port };
} catch {
return { name: origin };
}
}
/**
* The MCP client's endpoint: its address for Streamable HTTP, otherwise the
* transport name.
*
* @private
*/
function _client(r: FieldReader): Fields {
const ip = r.str("clientAddress");
const port = r.num("clientPort");
const transport = r.str("transport");
if (ip) {
return { ip, ...(port !== undefined ? { port } : {}) };
}
return { name: transport ?? "unknown" };
}
/**
* The URL of an upstream request: origin and path template, never a query.
*
* @private
*/
function _url(origin: string | undefined, path: string | undefined): Fields {
const url: Fields = { path };
if (origin) {
try {
const u = new URL(origin);
url.scheme = u.protocol.replace(/:$/, "");
url.hostname = u.hostname;
url.port = u.port ? Number(u.port) : undefined;
} catch {
// Not a URL; it is still reported as the destination endpoint.
}
}
return _compact(url);
}
/**
* The upstream request: method and URL.
*
* @private
*/
function _httpRequest(r: FieldReader, origin?: string): Fields | undefined {
const method = r.str("httpMethod");
const url = _url(origin, r.str("pathTemplate"));
const hasUrl = Object.keys(url).length > 0;
if (!method && !hasUrl) {
return undefined;
}
return _compact({ http_method: method, url: hasUrl ? url : undefined });
}
/**
* The actor: the authenticated caller, or oag-mcp itself.
*
* @private
*/
function _actor(r: FieldReader, product: OcsfProduct): Fields {
const principal = r.str("principalId");
return principal
? { user: { uid: principal } }
: {
app_name: product.name,
process: { pid: process.pid, name: product.name },
};
}
/**
* A copy of an object without its undefined values.
*
* @private
*/
function _compact(obj: Fields): Fields {
return Object.fromEntries(
Object.entries(obj).filter(([, v]) => v !== undefined),
);
}
/**
* Authentication of oag-mcp's own service identity to obtain an upstream
* OAuth token. The MCP request that needed the token is described as in API
* Activity: the caller as the actor and the client as the source endpoint.
* The execution id stays under `unmapped`: Authentication has `api` only
* through the Cloud profile, which describes cloud provider API calls.
*
* @private
*/
function _upstreamToken(r: FieldReader, product: OcsfProduct): Fields {
const status = r.num("status");
const fromRequest = r.has("clientAddress") || r.has("transport");
return _compact({
actor: _actor(r, product),
user: {
uid: r.str("provider") ?? "upstream",
type_id: 4,
type: "Service",
},
service: { name: r.str("scheme") },
auth_protocol_id: 6,
auth_protocol: "OAUTH 2.0",
status_code: status === undefined ? undefined : String(status),
src_endpoint: fromRequest ? _client(r) : undefined,
});
}
/**
* Authentication: an MCP caller, or oag-mcp's own service identity obtaining
* an upstream OAuth token.
*
* @private
*/
function _authentication(r: FieldReader, product: OcsfProduct): Fields {
if (r.has("scheme")) {
return _upstreamToken(r, product);
}
const principal = r.str("principalId");
const [protocolId, protocol] = AUTH_PROTOCOL[r.str("mode") ?? ""] ?? [
0,
"Unknown",
];
return {
user: principal
? { uid: principal }
: { name: "unknown", type_id: 0, type: "Unknown" },
service: { name: product.name, version: product.version },
auth_protocol_id: protocolId,
auth_protocol: protocol,
src_endpoint: _client(r),
};
}
/**
* API Activity: the `execute` tool call, or one SDK operation.
*
* @private
*/
function _apiActivity(r: FieldReader, product: OcsfProduct): Fields {
const operationId = r.str("operationId");
const executionId = r.str("executionId");
return _compact({
actor: _actor(r, product),
api: _compact({
operation: r.str("operation") ?? "execute",
request: executionId ? { uid: executionId } : undefined,
service: { name: product.name, version: product.version },
}),
src_endpoint: _client(r),
resources: operationId
? [{ uid: operationId, type: "OpenAPI operation" }]
: undefined,
http_request: _httpRequest(r),
});
}
/**
* HTTP Activity: an outbound call names the upstream, an inbound request
* the client.
*
* @private
*/
function _httpActivity(r: FieldReader, product: OcsfProduct): Fields {
const origin = r.str("destinationOrigin");
const endpoints = origin
? { dst_endpoint: _origin(origin) }
: { src_endpoint: _client(r), dst_endpoint: { svc_name: product.name } };
return _compact({
actor: _actor(r, product),
...endpoints,
http_request: _httpRequest(r, origin),
});
}
/**
* Process Activity: the Deno sandbox process.
*
* @private
*/
function _processActivity(r: FieldReader, product: OcsfProduct): Fields {
return {
actor: _actor(r, product),
device: { type_id: 1, type: "Server", hostname: os.hostname() },
process: _compact({
name: "deno",
pid: r.num("pid"),
uid: r.str("executionId"),
}),
};
}
/**
* Application Lifecycle: oag-mcp itself.
*
* @private
*/
function _applicationLifecycle(_r: FieldReader, product: OcsfProduct): Fields {
return {
app: _compact({
name: product.name,
version: product.version,
vendor_name: product.vendorName,
}),
};
}
/**
* Detection Finding: a forged bridge message from agent code.
*
* @private
*/
function _detectionFinding(r: FieldReader, product: OcsfProduct): Fields {
return {
actor: _actor(r, product),
finding_info: {
uid: crypto.randomUUID(),
title: "Agent code sent a forged bridge message",
types: ["Sandbox Boundary Violation"],
},
};
}
/** Class-specific attributes of each class. */
const CLASS_ATTRIBUTES: Readonly<
Record<OcsfClass, (r: FieldReader, product: OcsfProduct) => Fields>
> = {
authentication: _authentication,
api_activity: _apiActivity,
http_activity: _httpActivity,
process_activity: _processActivity,
application_lifecycle: _applicationLifecycle,
detection_finding: _detectionFinding,
};
/**
* The security control attributes of an allow or deny decision.
*
* @private
*/
function _control(outcome: AuditOutcome, r: FieldReader): Fields {
if (outcome !== "allowed" && outcome !== "denied") {
return {};
}
const stripped = r.take("strippedCredentials");
const policy = r.str("policyId");
const decision =
outcome === "denied"
? {
action_id: 2,
action: "Denied",
disposition_id: 2,
disposition: "Blocked",
}
: Array.isArray(stripped) && stripped.length > 0
? {
// Credentials supplied by agent code were removed.
action_id: 4,
action: "Modified",
disposition_id: 11,
disposition: "Corrected",
}
: {
action_id: 1,
action: "Allowed",
disposition_id: 1,
disposition: "Allowed",
};
return {
...decision,
...(policy ? { policy: { uid: policy } } : {}),
...(Array.isArray(stripped) ? { strippedCredentials: stripped } : {}),
};
}
/**
* The MCP tool call an event belongs to, as an AI Operation profile message
* context: oag-mcp acts as a tool (`ai_role_id` 3) in the client's session.
*
* @private
*/
function _messageContext(
cls: OcsfClass,
r: FieldReader,
product: OcsfProduct,
): Fields | undefined {
if (cls === "detection_finding" || !r.has("toolName")) {
return undefined;
}
const session = r.str("mcpSessionId");
const tool = r.str("toolName");
return {
...(session ? { uid: session } : {}),
name: `tools/call ${tool}`,
ai_role_id: 3,
ai_role: "Tool",
service: { name: product.name, version: product.version },
};
}
/** Classes whose `actor` comes from the host profile rather than the class. */
const HOST_PROFILE: ReadonlySet<OcsfClass> = new Set([
"http_activity",
"detection_finding",
]);
/**
* The classification attributes: category, class, activity and type.
*
* @private
*/
function _classification(spec: EventSpec): Fields {
const cls = CLASSES[spec.cls];
const activities: Record<number, string> = cls.activities;
const numbered = typeof spec.activity === "number";
const activityId = numbered ? (spec.activity as number) : OTHER;
const activityName = numbered
? activities[activityId]
: (spec.activity as string);
return {
category_uid: cls.category_uid,
category_name: cls.category_name,
class_uid: cls.uid,
class_name: cls.name,
activity_id: activityId,
activity_name: activityName,
type_uid: cls.uid * 100 + activityId,
type_name: `${cls.name}: ${activityName}`,
};
}
/**
* The severity and status attributes.
*
* @private
*/
function _outcome(
spec: EventSpec,
outcome: AuditOutcome,
level: AuditLevel,
r: FieldReader,
): Fields {
const severityId = spec.severityId ?? SEVERITY_ID[level];
const failed = outcome === "failure" || outcome === "denied";
const statusId = spec.statusId ?? (failed ? 2 : 1);
const duration = r.num("durationMs");
return _compact({
severity_id: severityId,
severity: SEVERITY_NAMES[severityId],
status_id: statusId,
// A finding's status is its lifecycle state: a new finding.
status: spec.cls === "detection_finding" ? "New" : STATUS_NAMES[statusId],
status_detail: r.str("reason"),
status_code: r.str("errorCode"),
duration,
});
}
/**
* The event metadata.
*
* @private
*/
function _metadata(
event: AuditEvent,
profiles: string[],
r: FieldReader,
product: OcsfProduct,
): Fields {
return _compact({
version: OCSF_VERSION,
uid: crypto.randomUUID(),
event_code: event,
profiles,
product: _compact({
name: product.name,
version: product.version,
vendor_name: product.vendorName,
}),
reporter: {
name: product.name,
uid: product.instanceId,
hostname: os.hostname(),
},
correlation_uid: r.str("requestId"),
});
}
/**
* The profiles an event uses beyond the class's own attributes.
*
* @private
*/
function _profiles(
cls: OcsfClass,
control: Fields,
messageContext: Fields | undefined,
): string[] {
return [
"datetime",
...(HOST_PROFILE.has(cls) ? ["host"] : []),
...(control.action_id !== undefined ? ["security_control"] : []),
...(messageContext ? ["ai_operation"] : []),
];
}
/**
* Convert a security audit event to an OCSF event.
*
* @param {String} event - oag-mcp event name
* @param {String} outcome - logged outcome
* @param {String} level - logged level
* @param {Object} fields - context and event fields, already redacted and
* bounded
* @param {Object} product - the recording oag-mcp instance
* @param {Number} [time] - event time in milliseconds (default: now)
* @return {Object} OCSF event (without `message`, which the logger adds)
*/
export function toOcsfEvent(
event: AuditEvent,
outcome: AuditOutcome,
level: AuditLevel,
fields: Fields,
product: OcsfProduct,
time: number = Date.now(),
): Fields {
const spec = (EVENTS[event] as (f: Fields) => EventSpec)(fields);
const r = new FieldReader(fields);
const classification = _classification(spec);
const outcomes = _outcome(spec, outcome, level, r);
const attributes = CLASS_ATTRIBUTES[spec.cls](r, product);
const messageContext = _messageContext(spec.cls, r, product);
const { strippedCredentials, ...control } = _control(outcome, r);
const metadata = _metadata(
event,
_profiles(spec.cls, control, messageContext),
r,
product,
);
const unmapped = _compact({ ...r.rest(), strippedCredentials });
return _compact({
time,
time_dt: new Date(time).toISOString(),
timezone_offset: 0,
...classification,
...outcomes,
metadata,
...attributes,
message_context: messageContext,
...control,
unmapped: Object.keys(unmapped).length > 0 ? unmapped : undefined,
});
}
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