# Improper Neutralization of Special Elements used in an LDAP Query ('LDAP Injection') (CWE-90)

The product constructs all or part of an LDAP query using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended LDAP query.

- Prevalence: High Frequently exploited
- Impact: High 3 high-severity rules
- Prevention: Documented 3 fix examples

**OWASP:** Injection (A03:2021-Injection) - #3

## Description

If user input is incorporated into an LDAP query without proper sanitization, an attacker can inject LDAP commands that could read or modify sensitive directory information.

## Prevention

Prevention strategies for LDAP Injection based on 3 Shoulder detection rules.

### Go

Use ldap.EscapeFilter to sanitize user input in LDAP queries

### Node.js

Escape LDAP special characters in user input before constructing LDAP queries

### Python

Escape LDAP special characters using escape_filter_chars() before constructing filters

## Warning Signs

- [HIGH] user input flowing to LDAP queries without proper escaping
- [HIGH] LDAP queries constructed with unsanitized user input

## Consequences

- Read Application Data
- Modify Application Data
- Bypass Protection Mechanism

## Mitigations

- Use parameterized LDAP queries where possible
- Escape or encode all user input used in LDAP queries
- Validate input against an allowlist of acceptable characters

## Detection

- Total rules: 3
- Languages: go, javascript, typescript, python

## Rules by Language

### Go (1 rules)

- **LDAP Injection** [HIGH]: Detects user input flowing to LDAP queries without proper escaping.
  - Remediation: Use ldap.EscapeFilter to sanitize user input before including in LDAP filters.

```go
escaped := ldap.EscapeFilter(username)
filter := fmt.Sprintf("(uid=%s)", escaped)
```

Learn more: https://shoulder.dev/learn/go/cwe-90/ldap-injection

### Javascript (1 rules)

- **LDAP Injection** [HIGH]: Detects user input flowing to LDAP queries without escaping special characters.
  - Remediation: Escape LDAP special characters before including user input in queries.

```javascript
const safe = input.replace(/[\\*()]/g, c =>
  '\\' + c.charCodeAt(0).toString(16));
ldap.search(`cn=${safe},dc=example,dc=com`, opts);
```

Learn more: https://shoulder.dev/learn/javascript/cwe-90/ldap-injection

### Typescript (1 rules)

- **LDAP Injection** [HIGH]: Detects user input flowing to LDAP queries without escaping special characters.
  - Remediation: Escape LDAP special characters before including user input in queries.

```javascript
const safe = input.replace(/[\\*()]/g, c =>
  '\\' + c.charCodeAt(0).toString(16));
ldap.search(`cn=${safe},dc=example,dc=com`, opts);
```

Learn more: https://shoulder.dev/learn/javascript/cwe-90/ldap-injection

### Python (1 rules)

- **LDAP Injection** [HIGH]: Detects LDAP queries constructed with unsanitized user input.
  - Remediation: Escape LDAP special characters using escape_filter_chars().

```python
from ldap3.utils.conv import escape_filter_chars
safe_username = escape_filter_chars(username)
```

Learn more: https://shoulder.dev/learn/python/cwe-90/ldap-injection