SQL Injection |
Attack Pattern ID: 66 (Standard Attack Pattern Completeness: Complete) | Typical Severity: High | Status: Draft |
Summary
This attack exploits target software that constructs SQL statements based on user input. An attacker crafts input strings so that when the target software constructs SQL statements based on the input, the resulting SQL statement performs actions other than those the application intended.
SQL Injection results from failure of the application to appropriately validate input. When specially crafted user-controlled input consisting of SQL syntax is used without proper validation as part of SQL queries, it is possible to glean information from the database in ways not envisaged during application design. Depending upon the database and the design of the application, it may also be possible to leverage injection to have the database execute system-related commands of the attacker's choice. SQL Injection enables an attacker to talk directly to the database, thus bypassing the application completely. Sucessful injection can cause information disclosure as well as ability to add or modify data in the database. In order to successfully inject SQL and retrieve information from a database, an attacker:
Attack Execution Flow
Survey application:
The attacker first takes an inventory of the functionality exposed by the application.
Attack Step Techniques
ID Attack Step Technique Description Environments 1 Spider web sites for all available links
env-Web2 Sniff network communications with application using a utility such as WireShark.
env-ClientServer env-Peer2Peer env-CommProtocolOutcomes
ID type Outcome Description 1 Success At least one data input to application identified.2 Failure No inputs to application identified. Note that just because no inputs are identified does not mean that the application will not accept any.
Determine user-controllable input susceptible to injection:
Determine the user-controllable input susceptible to injection. For each user-controllable input that the attacker suspects is vulnerable to SQL injection, attempt to inject characters that have special meaning in SQL (such as a single quote character, a double quote character, two hyphens, a paranthesis, etc.). The goal is to create a SQL query with an invalid syntax.
Attack Step Techniques
ID Attack Step Technique Description Environments 1 Use web browser to inject input through text fields or through HTTP GET parameters.
env-Web2 Use a web application debugging tool such as Tamper Data, TamperIE, WebScarab,etc. to modify HTTP POST parameters, hidden fields, non-freeform fields, etc.
env-Web3 Use network-level packet injection tools such as netcat to inject input
env-Web env-ClientServer env-Peer2Peer env-CommProtocol4 Use modified client (modified by reverse engineering) to inject input.
env-ClientServer env-Peer2Peer env-CommProtocolIndicators
ID type Indicator Description Environments 1 Negative Attacker receives normal response from server.
env-Web env-ClientServer env-Peer2Peer env-CommProtocol2 Positive Attacker receives an error message from server indicating that there was a problem with the SQL query.
env-Web env-ClientServer env-Peer2Peer env-CommProtocol3 Negative Server sends a specific error message that indicates programmatic parsing of the input data (e.g. NumberFormatException)
env-Web env-ClientServer env-Peer2Peer env-CommProtocolOutcomes
ID type Outcome Description 1 Success At least one user-controllable input susceptible to injection found.2 Failure No user-controllable input susceptible to injection found.Security Controls
ID type Security Control Description 1 Detective Search for and alert on unexpected SQL keywords in application logs (e.g. SELECT, DROP, etc.).2 Preventative Input validation of user-controlled data before including it in a SQL query3 Preventative Use parameterized queries (e.g. PreparedStatement in Java, and Command.Parameters.Add() to set query parameters in .NET)Experiment and try to exploit SQL Injection vulnerability:
After determining that a given input is vulnerable to SQL Injection, hypothesize what the underlying query looks like. Iteratively try to add logic to the query to extract information from the database, or to modify or delete information in the database.
Attack Step Techniques
ID Attack Step Technique Description Environments 1 Use public resources such as "SQL Injection Cheat Sheet" at http://ferruh.mavituna.com/makale/sql-injection-cheatsheet/, and try different approaches for adding logic to SQL queries.
env-Web env-ClientServer env-Peer2Peer env-CommProtocol2 Add logic to query, and use detailed error messages from the server to debug the query. For example, if adding a single quote to a query causes an error message, try : "' OR 1=1; --", or something else that would syntactically complete a hypothesized query. Iteratively refine the query.
env-Web env-ClientServer env-Peer2Peer env-CommProtocol3 Use "Blind SQL Injection" techniques to extract information about the database schema.
env-Web env-ClientServer env-Peer2Peer env-CommProtocol4 If a denial of service attack is the goal, try stacking queries. This does not work on all platforms (most notably, it does not work on Oracle or MySQL). Examples of inputs to try include: "'; DROP TABLE SYSOBJECTS; --" and "'); DROP TABLE SYSOBJECTS; --". These particular queries will likely not work because the SYSOBJECTS table is generally protected.
env-Web env-ClientServer env-Peer2Peer env-CommProtocolIndicators
ID type Indicator Description Environments 1 Positive Success outcome in previous step.
env-Web env-ClientServer env-Peer2Peer env-CommProtocol2 Negative Failure outcome in previous step.
env-Web env-ClientServer env-Peer2Peer env-CommProtocolOutcomes
ID type Outcome Description 1 Success Attacker achieves goal of unauthorized system access, denial of service, etc.2 Failure Attacker unable to exploit SQL Injection vulnerability.
SQL queries used by the application to store, retrieve or modify data.
User-controllable input that is not properly validated by the application as part of SQL queries.
Description
With PHP-Nuke versions 7.9 and earlier, an attacker can successfully access and modify data, including sensitive contents such as usernames and password hashes, and compromise the application through SQL Injection. The protection mechanism against SQL Injection employs a blacklist approach to input validation. However, because of improper blacklisting, it is possible to inject content such as "foo'/**/UNION" or "foo UNION/**/" to bypass validation and glean sensitive information from the database.
Related Vulnerabilities
CVE-2006-5525
Skill or Knowledge Level: Low
It is fairly simple for someone with basic SQL knowledge to perform SQL injection, in general. In certain instances, however, specific knowledge of the database employed may be required.
The attacker tries to inject characters that can cause a SQL error, such as single-quote (') or keywords such as "UNION" and "OR". If the injection of such characters into the input causes a SQL error and the resulting error is displayed unfiltered, the attacker can begin to determine the nature of input validation and structure of SQL queries. A typical error resulting from such injection would look like:
With available design documentation and code, the attacker can determine whether all user-controllable inputs are being validated or not, and also the structure of SQL queries that such inputs feed into.
Too many false or invalid queries to the database, especially those caused by malformed input.
Strong input validation - All user-controllable input must be validated and filtered for illegal characters as well as SQL content. Keywords such as UNION, SELECT or INSERT must be filtered in addition to characters such as a single-quote(') or SQL-comments (--) based on the context in which they appear.
Use of parameterized queries or stored procedures - Parameterization causes the input to be restricted to certain domains, such as strings or integers, and any input outside such domains is considered invalid and the query fails. Note that SQL Injection is possible even in the presence of stored procedures if the eventual query is constructed dynamically.
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 database or application.
- Data Modification
- Information Leakage
- Run Arbitrary Code
- Privilege Escalation
User-controllable input used as part of non-parameterized SQL queries: This may include input fields on web forms, data in user-accessible files or even command-line parameters.
When malicious SQL content is executed by the database, it can lead to arbitrary queries being executed, causing disclosure of information, unauthorized access, privilege escalation and possibly system compromise.
CWE-ID | Weakness Name | Weakness Relationship Type |
---|---|---|
89 | Improper Sanitization of Special Elements used in an SQL Command ('SQL Injection') | Targeted |
74 | Failure to Sanitize Data into a Different Plane ('Injection') | Secondary |
20 | Improper Input Validation | Secondary |
390 | Detection of Error Condition Without Action | Secondary |
697 | Insufficient Comparison | Secondary |
713 | OWASP Top Ten 2007 Category A2 - Injection Flaws | Secondary |
707 | Improper Enforcement of Message or Data Structure | Secondary |
Nature | Type | ID | Name | Description | View(s) this relationship pertains to |
---|---|---|---|---|---|
ChildOf | Category | 152 | Injection (Injecting Control Plane content through the Data Plane) | Mechanism of Attack (primary)1000 | |
ChildOf | Category | 352 | WASC Threat Classification 2.0 - WASC-19 - SQL Injection | WASC Threat Classification 2.0333 | |
CanFollow | Attack Pattern | 7 | Blind SQL Injection | Mechanism of Attack1000 | |
ParentOf | Attack Pattern | 7 | Blind SQL Injection | Mechanism of Attack (primary)1000 | |
ParentOf | Attack Pattern | 109 | Object Relational Mapping Injection | Mechanism of Attack (primary)1000 | |
ParentOf | Attack Pattern | 110 | SQL Injection through SOAP Parameter Tampering | Mechanism of Attack (primary)1000 |
Special characters in user-controllable input must be escaped before use by the application.
Only use parameterized stored procedures to query the database.
Input data must be revalidated in the parameterized stored procedures.
Custom error pages must be used to handle exceptions such that they do not reveal any information about the architecture of the application or the database.
Never Use Input as Part of a Directive to any Internal Component
Handle All Errors Safely
Submissions | ||||
---|---|---|---|---|
Submitter | Date | Comments | ||
Chiradeep B Chhaya | 2007-01-12 | Second Draft |
Modifications | |||||
---|---|---|---|---|---|
Modifier | Organization | Date | Comments | ||
Malik Hamro | Cigital, Inc | 2007-02-27 | Reformat to new schema and review | ||
Sean Barnum | Cigital, Inc | 2007-03-05 | Review and revise | ||
Richard Struse | VOXEM, Inc | 2007-03-26 | Review and feedback leading to changes in Description and Related Attack Patterns | ||
Sean Barnum | Cigital, Inc | 2007-04-13 | Modified pattern content according to review and feedback |