SqlStringConcat [anti-pattern] v1.0.0

Building SQL queries by concatenating or interpolating user-controlled strings directly into query text — the classic SQL injection (SQLi) vulnerability, #1 on OWASP for over a decade.

Label

SQL String Concatenation with User Input

Why Bad

User input becomes query syntax. The canonical example: SELECT * FROM users WHERE id=' + userId + '' — when userId = ' OR 1=1 -- the query becomes SELECT * FROM users WHERE id='' OR 1=1 -- ' which returns all users. From there: UNION SELECT username, password FROM admins; table drops; file reads (LOAD DATA INFILE); and in misconfigured DBs, OS command execution (xp_cmdshell in MSSQL). SQLi requires no authentication, is remotely exploitable, and has been the root cause of major breaches for 25 years.

Instead Do

Use parameterized queries (prepared statements) exclusively. The query structure is compiled separately from the data — user input is always treated as a value, never as SQL syntax. ORMs provide parameterization by default when using their query builders; only raw() / literal() escape hatches bypass this.

Structure

    # WRONG — string concatenation
    const query = "SELECT * FROM users WHERE email='" + email + "'";
    db.query(query);   // SQLi: email = "' OR 1=1 --"

    # WRONG — template literal (same problem, just prettier)
    const query = `SELECT * FROM products WHERE id=${req.params.id}`;

    # CORRECT — parameterized query (node-postgres)
    const { rows } = await pool.query(
      'SELECT * FROM users WHERE email = $1 AND active = $2',
      [email, true]   // values are passed separately, never interpolated
    );

    # CORRECT — parameterized (MySQL2)
    const [rows] = await pool.execute(
      'SELECT * FROM users WHERE email = ? AND active = ?',
      [email, true]
    );

    # CORRECT — ORM (Prisma)
    const user = await prisma.user.findFirst({
      where: { email, active: true },   // query builder parameterizes automatically
    });

    # CORRECT — ORM (Prisma raw when needed)
    const result = await prisma.$queryRaw`
      SELECT * FROM users WHERE email = ${email}
    `;   // Prisma tagged template literal = parameterized

    # WRONG — Prisma raw escape hatch (dangerous)
    await prisma.$queryRawUnsafe(`SELECT * FROM users WHERE email = '${email}'`);

    # Python / SQLAlchemy
    result = db.execute(
      text("SELECT * FROM users WHERE email = :email"),
      {"email": email}
    )
  

SqlStringConcat [anti-pattern] v1.0.0

Building SQL queries by concatenating or interpolating user-controlled strings directly into query text — the classic SQL injection (SQLi) vulnerability, #1 on OWASP for over a decade.

Label

SQL String Concatenation with User Input

Why Bad

User input becomes query syntax. The canonical example: SELECT * FROM users WHERE id=' + userId + '' — when userId = ' OR 1=1 -- the query becomes SELECT * FROM users WHERE id='' OR 1=1 -- ' which returns all users. From there: UNION SELECT username, password FROM admins; table drops; file reads (LOAD DATA INFILE); and in misconfigured DBs, OS command execution (xp_cmdshell in MSSQL). SQLi requires no authentication, is remotely exploitable, and has been the root cause of major breaches for 25 years.

Instead Do

Use parameterized queries (prepared statements) exclusively. The query structure is compiled separately from the data — user input is always treated as a value, never as SQL syntax. ORMs provide parameterization by default when using their query builders; only raw() / literal() escape hatches bypass this.

Structure

    # WRONG — string concatenation
    const query = "SELECT * FROM users WHERE email='" + email + "'";
    db.query(query);   // SQLi: email = "' OR 1=1 --"

    # WRONG — template literal (same problem, just prettier)
    const query = `SELECT * FROM products WHERE id=${req.params.id}`;

    # CORRECT — parameterized query (node-postgres)
    const { rows } = await pool.query(
      'SELECT * FROM users WHERE email = $1 AND active = $2',
      [email, true]   // values are passed separately, never interpolated
    );

    # CORRECT — parameterized (MySQL2)
    const [rows] = await pool.execute(
      'SELECT * FROM users WHERE email = ? AND active = ?',
      [email, true]
    );

    # CORRECT — ORM (Prisma)
    const user = await prisma.user.findFirst({
      where: { email, active: true },   // query builder parameterizes automatically
    });

    # CORRECT — ORM (Prisma raw when needed)
    const result = await prisma.$queryRaw`
      SELECT * FROM users WHERE email = ${email}
    `;   // Prisma tagged template literal = parameterized

    # WRONG — Prisma raw escape hatch (dangerous)
    await prisma.$queryRawUnsafe(`SELECT * FROM users WHERE email = '${email}'`);

    # Python / SQLAlchemy
    result = db.execute(
      text("SELECT * FROM users WHERE email = :email"),
      {"email": email}
    )
  

Label

SQL String Concatenation with User Input

Why Bad

User input becomes query syntax. The canonical example: SELECT * FROM users WHERE id=' + userId + '' — when userId = ' OR 1=1 -- the query becomes SELECT * FROM users WHERE id='' OR 1=1 -- ' which returns all users. From there: UNION SELECT username, password FROM admins; table drops; file reads (LOAD DATA INFILE); and in misconfigured DBs, OS command execution (xp_cmdshell in MSSQL). SQLi requires no authentication, is remotely exploitable, and has been the root cause of major breaches for 25 years.

Instead Do

Use parameterized queries (prepared statements) exclusively. The query structure is compiled separately from the data — user input is always treated as a value, never as SQL syntax. ORMs provide parameterization by default when using their query builders; only raw() / literal() escape hatches bypass this.

Structure

    # WRONG — string concatenation
    const query = "SELECT * FROM users WHERE email='" + email + "'";
    db.query(query);   // SQLi: email = "' OR 1=1 --"

    # WRONG — template literal (same problem, just prettier)
    const query = `SELECT * FROM products WHERE id=${req.params.id}`;

    # CORRECT — parameterized query (node-postgres)
    const { rows } = await pool.query(
      'SELECT * FROM users WHERE email = $1 AND active = $2',
      [email, true]   // values are passed separately, never interpolated
    );

    # CORRECT — parameterized (MySQL2)
    const [rows] = await pool.execute(
      'SELECT * FROM users WHERE email = ? AND active = ?',
      [email, true]
    );

    # CORRECT — ORM (Prisma)
    const user = await prisma.user.findFirst({
      where: { email, active: true },   // query builder parameterizes automatically
    });

    # CORRECT — ORM (Prisma raw when needed)
    const result = await prisma.$queryRaw`
      SELECT * FROM users WHERE email = ${email}
    `;   // Prisma tagged template literal = parameterized

    # WRONG — Prisma raw escape hatch (dangerous)
    await prisma.$queryRawUnsafe(`SELECT * FROM users WHERE email = '${email}'`);

    # Python / SQLAlchemy
    result = db.execute(
      text("SELECT * FROM users WHERE email = :email"),
      {"email": email}
    )