Secure Code Review (SCR) : A1 Injection

Secure Code Review: A1 Injection

Secure Code Review: A1 Injection

In the world of software development, security is a crucial aspect that cannot be overlooked. One of the most common and dangerous vulnerabilities that can plague your code is Injection. Injection flaws, such as SQL, NoSQL, OS, and LDAP injection, occur when untrusted data is sent to an interpreter as part of a command or query. The attacker’s hostile data can trick the interpreter into executing unintended commands or accessing unauthorized data. In this blog post, we will delve into the details of Injection vulnerabilities, how to identify them during a secure code review, and what measures can be taken to prevent them.

Understanding Injection Vulnerabilities

Injection vulnerabilities arise when an application sends untrusted data to an interpreter or a database. This untrusted data, if not properly validated or escaped, can lead to the execution of malicious commands that can compromise the security of the application. Injection attacks can lead to data loss, corruption, or disclosure to unauthorized parties, loss of accountability, or denial of access.

The most common form of injection vulnerability is SQL Injection, where an attacker manipulates SQL queries to execute arbitrary commands in the database. However, injection vulnerabilities are not limited to SQL and can occur in other contexts like OS commands, LDAP queries, XML parsers, or any situation where the application invokes an interpreter.

Identifying Injection Vulnerabilities in Code Review

During a secure code review, the primary goal is to identify places in the code where untrusted data is used to form a command or a query that is then executed or interpreted. Here are some things to look for:

  1. User-supplied data in queries or commands: Anytime the application uses data supplied by the user to form a query or a command, it’s a potential injection point. This includes data from HTTP requests, forms, cookies, or any external sources.
  2. Lack of validation or sanitization of user-supplied data: If the application does not validate or sanitize user-supplied data before including it in a query or a command, it’s a potential injection vulnerability.
  3. Use of concatenation or string formatting to form queries or commands: If the application uses concatenation or string formatting functions to include user-supplied data in a query or a command, it’s a potential injection point.
  4. Lack of parameterized queries or prepared statements: If the application does not use parameterized queries or prepared statements for database access, it’s more susceptible to SQL injection attacks.

Checklist for Secure Code Review against Injection Vulnerabilities

Here is a checklist to follow when performing a secure code review to identify injection vulnerabilities:

  1. Identify all points in the code where the application uses user-supplied data to form a query or a command.
  2. Check if the application validates or sanitizes the user-supplied data before using it in a query or a command.
  3. Check if the application uses safe methods like parameterized queries or prepared statements for database access.
  4. Check if the application uses proper error handling mechanisms to prevent leakage of sensitive information in case of an error.
  5. Check if the application uses least privilege principle for database access, i.e., it does not use a highly privileged account for database operations.

Preventing Injection Vulnerabilities

Preventing injection vulnerabilities involves proper design and coding practices. Here are some measures that can be taken:

  1. Use safe APIs: Use APIs that automatically escape special characters or parameterized inputs like prepared statements in SQL.
  2. Validate and sanitize user input: Always validate user-supplied data for length, type, syntax, and business rules. Sanitize the data to ensure it does not contain any characters or sequences that can be interpreted in a malicious way.
  3. Least privilege: Ensure that the application uses an account with the least privileges necessary when connecting to databases or other resources.
  4. Error handling: Implement proper error handling so that errors do not disclose any sensitive information or provide clues to attackers.
  5. Regular updates: Regularly update and patch all systems to ensure any known vulnerabilities are addressed.

In conclusion, injection vulnerabilities are a serious threat to application security, but they can be effectively mitigated with proper coding and design practices. A thorough secure code review is a crucial step in identifying and fixing these vulnerabilities before the application goes into production.

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References:

  1. https://owasp.org/www-project-code-review-guide/assets/OWASP_Code_Review_Guide_v2.pdf