fix(security): unify secret redaction in public comment outputs (#1693)

Ensure all public issue, PR, and inline comments apply redactSecrets() in addition to sanitizeContent() before submitting payloads to the GitHub API. This aligns public comment output with error log and step-summary redaction policies, preventing potential leakage of Anthropic API keys, AWS credentials, Slack tokens, JWTs, and GitHub tokens.

src/entrypoints/post-buffered-inline-comments.ts

@@ -11,6 +11,7 @@
  */
 import { readFileSync } from "fs";
 import { createOctokit } from "../github/api/client";
+import { redactSecrets } from "../github/utils/sanitizer";
 
 const BUFFER_PATH = "/tmp/inline-comments-buffer.jsonl";
 
@@ -120,7 +121,7 @@ async function postComment(
     owner,
     repo,
     pull_number,
-    body: c.body,
+    body: redactSecrets(c.body),
     path: c.path,
     side: c.side || "RIGHT",
     commit_id: c.commit_id || headSha,

src/mcp/github-comment-server.ts

@@ -6,7 +6,7 @@ import { z } from "zod";
 import { GITHUB_API_URL } from "../github/api/config";
 import { Octokit } from "@octokit/rest";
 import { updateClaudeComment } from "../github/operations/comments/update-claude-comment";
-import { sanitizeContent } from "../github/utils/sanitizer";
+import { redactSecrets, sanitizeContent } from "../github/utils/sanitizer";
 
 // Get repository information from environment variables
 const REPO_OWNER = process.env.REPO_OWNER;
@@ -55,7 +55,7 @@ server.tool(
       const isPullRequestReviewComment =
         eventName === "pull_request_review_comment";
 
-      const sanitizedBody = sanitizeContent(body);
+      const sanitizedBody = redactSecrets(sanitizeContent(body));
 
       const result = await updateClaudeComment(octokit, {
         owner,

src/mcp/github-inline-comment-server.ts

@@ -4,7 +4,7 @@ import { StdioServerTransport } from "@modelcontextprotocol/sdk/server/stdio.js"
 import { appendFileSync } from "fs";
 import { z } from "zod";
 import { createOctokit } from "../github/api/client";
-import { sanitizeContent } from "../github/utils/sanitizer";
+import { redactSecrets, sanitizeContent } from "../github/utils/sanitizer";
 import { removeBufferedComment } from "./inline-comment-buffer";
 
 // Get repository and PR information from environment variables
@@ -98,8 +98,8 @@ server.tool(
       const repo = REPO_NAME;
       const pull_number = parseInt(PR_NUMBER, 10);
 
-      // Sanitize the comment body to remove any potential GitHub tokens
-      const sanitizedBody = sanitizeContent(body);
+      // Sanitize the comment body to remove potential prompt injections and redact secrets
+      const sanitizedBody = redactSecrets(sanitizeContent(body));
 
       // Validate that either line or both startLine and line are provided
       if (!line && !startLine) {

test/public-comment-redaction.test.ts

@@ -0,0 +1,64 @@
+import { describe, expect, it } from "bun:test";
+import { redactSecrets, sanitizeContent } from "../src/github/utils/sanitizer";
+
+describe("Public Comment Output Sanitization & Redaction", () => {
+  it("redacts all credential types from public comment output", () => {
+    const rawComment = [
+      "Here is the summary of the work done:",
+      "- GitHub Token: ghp_ABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890",
+      "- Anthropic Key: sk-ant-api03-abcdefghijklmnopqrstuvwxyz1234567890",
+      "- AWS Access Key: AKIAIOSFODNN7EXAMPLE",
+      "- Slack Bot Token: xoxb-1234567890-abcdefghijkl-mnopqrstuvwx",
+      "- JWT Bearer: eyJhbGciOiJIUzI1NiJ9.eyJzdWIiOiIxMjM0NTY3ODkwIn0.dozjgNryP4J3jVmNHl0w5N_XgL0n3I9PlFUP0THsR8U",
+      "<!-- Hidden instruction injection -->",
+      "Invisible\u200Bzero-width chars",
+      "![Image Alt Injection](https://example.com/pic.png)",
+    ].join("\n");
+
+    const sanitizedOutput = redactSecrets(sanitizeContent(rawComment));
+
+    // Ensure all secret types are redacted
+    expect(sanitizedOutput).not.toContain(
+      "ghp_ABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890",
+    );
+    expect(sanitizedOutput).not.toContain(
+      "sk-ant-api03-abcdefghijklmnopqrstuvwxyz1234567890",
+    );
+    expect(sanitizedOutput).not.toContain("AKIAIOSFODNN7EXAMPLE");
+    expect(sanitizedOutput).not.toContain(
+      "xoxb-1234567890-abcdefghijkl-mnopqrstuvwx",
+    );
+    expect(sanitizedOutput).not.toContain(
+      "eyJhbGciOiJIUzI1NiJ9.eyJzdWIiOiIxMjM0NTY3ODkwIn0.dozjgNryP4J3jVmNHl0w5N_XgL0n3I9PlFUP0THsR8U",
+    );
+
+    expect(sanitizedOutput).toContain("[REDACTED_GITHUB_TOKEN]");
+    expect(sanitizedOutput).toContain("[REDACTED_ANTHROPIC_KEY]");
+    expect(sanitizedOutput).toContain("[REDACTED_AWS_KEY_ID]");
+    expect(sanitizedOutput).toContain("[REDACTED_SLACK_TOKEN]");
+    expect(sanitizedOutput).toContain("[REDACTED_JWT]");
+
+    // Ensure prompt injection / invisible chars / hidden tags are also sanitized
+    expect(sanitizedOutput).not.toContain(
+      "<!-- Hidden instruction injection -->",
+    );
+    expect(sanitizedOutput).not.toContain("\u200B");
+    expect(sanitizedOutput).not.toContain("Image Alt Injection");
+    expect(sanitizedOutput).toContain("![](https://example.com/pic.png)");
+  });
+
+  it("ensures public comments have the same secret redaction coverage as logs/errors", () => {
+    const errorDetails =
+      "Error: failed to connect with sk-ant-abcdefghijklmnopqrstuvwxyz123456 and AKIAIOSFODNN7EXAMPLE";
+    const commentBody =
+      "Report: encountered sk-ant-abcdefghijklmnopqrstuvwxyz123456 and AKIAIOSFODNN7EXAMPLE";
+
+    const redactedError = redactSecrets(errorDetails);
+    const redactedComment = redactSecrets(sanitizeContent(commentBody));
+
+    expect(redactedError).toContain("[REDACTED_ANTHROPIC_KEY]");
+    expect(redactedError).toContain("[REDACTED_AWS_KEY_ID]");
+    expect(redactedComment).toContain("[REDACTED_ANTHROPIC_KEY]");
+    expect(redactedComment).toContain("[REDACTED_AWS_KEY_ID]");
+  });
+});

test/sanitizer.test.ts

@@ -518,3 +518,28 @@ describe("stripHtmlComments (legacy)", () => {
     );
   });
 });
+
+describe("outbound comment sanitization and redaction", () => {
+  it("should sanitize content and redact all credential types for public comments", () => {
+    const rawComment =
+      "Done! Configured AWS AKIAIOSFODNN7EXAMPLE, Anthropic sk-ant-api03-abcdefghijklmnopqrstuvwxyz1234567890, Slack xoxb-1234567890-abcdefghijkl-mnopqrstuvwx, and GitHub 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 <!-- secret note -->";
+    const sanitizedAndRedacted = redactSecrets(sanitizeContent(rawComment));
+
+    expect(sanitizedAndRedacted).not.toContain("AKIAIOSFODNN7EXAMPLE");
+    expect(sanitizedAndRedacted).not.toContain(
+      "sk-ant-api03-abcdefghijklmnopqrstuvwxyz1234567890",
+    );
+    expect(sanitizedAndRedacted).not.toContain(
+      "xoxb-1234567890-abcdefghijkl-mnopqrstuvwx",
+    );
+    expect(sanitizedAndRedacted).not.toContain(
+      "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",
+    );
+    expect(sanitizedAndRedacted).not.toContain("secret note");
+
+    expect(sanitizedAndRedacted).toContain("[REDACTED_AWS_KEY_ID]");
+    expect(sanitizedAndRedacted).toContain("[REDACTED_ANTHROPIC_KEY]");
+    expect(sanitizedAndRedacted).toContain("[REDACTED_SLACK_TOKEN]");
+    expect(sanitizedAndRedacted).toContain("[REDACTED_GITHUB_TOKEN]");
+  });
+});