COMMON ATTACK PATTERN ENUMERATION AND CLASSIFICATIONLive MITRE record

CAPEC-136

LDAP Injection

An attacker manipulates or crafts an LDAP query for the purpose of undermining the security of the target. Some applications use user input to create LDAP queries that are processed by an LDAP server. For example, a user might provide their username during authentication and the username might be inserted in an LDAP query during the authentication process. An attacker could use this input to inject additional commands into an LDAP query that could disclose sensitive information. For example, entering a * in the aforementioned query might return information about all users on the system. This attack is very similar to an SQL injection attack in that it manipulates a query to gather additional information or coerce a particular return value.

Abstraction

Standard

Typical severity

High

Likelihood of attack

High

Understand the attack

What is this attack pattern?

An attacker manipulates or crafts an LDAP query for the purpose of undermining the security of the target. Some applications use user input to create LDAP queries that are processed by an LDAP server. For example, a user might provide their username during authentication and the username might be inserted in an LDAP query during the authentication process. An attacker could use this input to inject additional commands into an LDAP query that could disclose sensitive information. For example, entering a * in the aforementioned query might return information about all users on the system. This attack is very similar to an SQL injection attack in that it manipulates a query to gather additional information or coerce a particular return value.

Execution flow

How does the attack proceed, step by step?

1

Explore

Survey application

The attacker takes an inventory of the entry points of the application.

Techniques used

  • Spider web sites for all available links
  • Sniff network communications with application using a utility such as WireShark.
2

Experiment

Determine user-controllable input susceptible to LDAP injection

For each user-controllable input that the attacker suspects is vulnerable to LDAP injection, attempt to inject characters that have special meaning in LDAP (such as a single quote character, etc.). The goal is to create a LDAP query with an invalid syntax

Techniques used

  • Use web browser to inject input through text fields or through HTTP GET parameters
  • Use a web application debugging tool such as Tamper Data, TamperIE, WebScarab,etc. to modify HTTP POST parameters, hidden fields, non-freeform fields, or other HTTP header.
  • Use modified client (modified by reverse engineering) to inject input.

Try to exploit the LDAP injection vulnerability

After determining that a given input is vulnerable to LDAP Injection, hypothesize what the underlying query looks like. Possibly using a tool, iteratively try to add logic to the query to extract information from the LDAP, or to modify or delete information in the LDAP.

Techniques used

  • Add logic to the LDAP query to change the meaning of that command. Automated tools could be used to generate the LDAP injection strings.
  • Use a web application debugging tool such as Tamper Data, TamperIE, WebScarab,etc. to modify HTTP POST parameters, hidden fields, non-freeform fields, or other HTTP header.

Requirements

What does the attack require?

Prerequisites

  • The target application must accept a string as user input, fail to sanitize characters that have a special meaning in LDAP queries in the user input, and insert the user-supplied string in an LDAP query which is then processed.

Skills required

  • Medium: The attacker needs to have knowledge of LDAP, especially its query syntax.

Resources required

Not stated in the MITRE record.

Impact

What does a successful attack lead to?

Unreliable Execution

Affected scopes: Availability

Modify Data

Affected scopes: Integrity

Read Data

Affected scopes: Confidentiality

Execute Unauthorized Commands

Affected scopes: Authorization

Gain Privileges

Affected scopes: Accountability, Authentication, Authorization, Non-Repudiation

Bypass Protection Mechanism

Affected scopes: Access Control, Authorization

Defence

How is it prevented and mitigated?

1
Strong input validation - All user-controllable input must be validated and filtered for illegal characters as well as LDAP content.
2
Use of custom error pages - Attackers can glean information about the nature of queries from descriptive error messages. Input validation must be coupled with customized error pages that inform about an error without disclosing information about the LDAP or application.

Real world

MITRE example instances

Example instance 1Detail
PowerDNS before 2.9.18, when running with an LDAP backend, does not properly escape LDAP queries, which allows remote attackers to cause a denial of service (failure to answer ldap questions) and possibly conduct an LDAP injection attack. See also: CVE-2005-2301
CAPEC-136: LDAP Injection — DayBreach Saldırı Sözlüğü · DayBreach