Reliance on Cookies without Validation and Integrity Checking

Opis

The product relies on the existence or values of cookies when performing security-critical operations, but it does not properly ensure that the setting is valid for the associated user.

Skutki

• Confidentiality, Integrity, Availability

  Modify Application Data; Execute Unauthorized Code or Commands

  Attackers can easily modify cookies, within the browser or by implementing the client-side code outside of the browser. Reliance on cookies without detailed validation and integrity checking can allow attackers to bypass authentication, conduct injection attacks such as SQL injection and cross-site scripting, or otherwise modify inputs in unexpected ways.

• Access Control

  Gain Privileges or Assume Identity

  It is dangerous to use cookies to set a user's privileges. The cookie can be manipulated to escalate an attacker's privileges to an administrative level.

Zapobieganie

• Architecture and Design

  Avoid using cookie data for a security-related decision.

• Implementation

  Perform thorough input validation (i.e.: server side validation) on the cookie data if you're going to use it for a security related decision.

• Architecture and Design

  Add integrity checks to detect tampering.

• Architecture and Design

  Protect critical cookies from replay attacks, since cross-site scripting or other attacks may allow attackers to steal a strongly-encrypted cookie that also passes integrity checks. This mitigation applies to cookies that should only be valid during a single transaction or session. By enforcing timeouts, you may limit the scope of an attack. As part of your integrity check, use an unpredictable, server-side value that is not exposed to the client.

Przykłady podatności

• CVE-2008-5784 e-dating application allows admin privileges by setting the admin cookie to 1.

Słabość nadrzędna

• CWE-642 External Control of Critical State Data
• CWE-669 Incorrect Resource Transfer Between Spheres
• CWE-602 Client-Side Enforcement of Server-Side Security

Słabości podrzędne

• CWE-784 Reliance on Cookies without Validation and Integrity Checking in a Security Decision

Kiedy powstaje

• Architecture and Design — OMISSION: This weakness is caused by missing a security tactic during the architecture and design phase.
• Implementation

Dotyczy

Not Language-Specific

Uwagi

This problem can be primary to many types of weaknesses in web applications. A developer may perform proper validation against URL parameters while assuming that attackers cannot modify cookies. As a result, the program might skip basic input validation to enable cross-site scripting, SQL injection, price tampering, and other attacks..