External Control of Assumed-Immutable Web Parameter |
Weakness ID: 472 (Weakness Base) | Status: Draft |
Description Summary
Extended Description
If a web product does not properly protect assumed-immutable values from modification in hidden form fields, parameters, cookies, or URLs, this can lead to modification of critical data. Web applications often mistakenly make the assumption that data passed to the client in hidden fields or cookies is not susceptible to tampering. Failure to validate portions of data that are user-controllable can lead to the application processing incorrect, and often malicious, input.
For example, custom cookies commonly store session data or persistent data across sessions. This kind of session data is normally involved in security related decisions on the server side, such as user authentication and access control. Thus, the cookies might contain sensitive data such as user credentials and privileges. This is a dangerous practice, as it can often lead to improper reliance on the value of the client-provided cookie by the server side application.
Scope | Effect |
---|---|
Integrity | Without appropriate protection mechanisms, the client can easily tamper with cookies and similar web data. Reliance on the cookies without detailed validation can lead to problems such as SQL injection. If you use cookie values for security related decisions on the server side, manipulating the cookies might lead to violations of security policies such as authentication bypassing, user impersonation and privilege escalation. In addition, storing sensitive data in the cookie without appropriate protection can also lead to disclosure of sensitive user data, especially data stored in persistent cookies. |
Example 1
Here, a web application uses the value of a hidden form field (accountID) without having done any input validation because it was assumed to be immutable.
Example 2
Hidden fields should not be trusted as secure parameters. An attacker can intercept and alter hidden fields in a post to the server as easily as user input fields. An attacker can simply parse the HTML for the substring:
or even just "hidden". Hidden field values displayed later in the session, such as on the following page, can open a site up to cross-site scripting attacks.
Reference | Description |
---|---|
CVE-2002-0108 | Forum product allows spoofed messages of other users via hidden form fields for name and e-mail address. |
CVE-2000-0253 | Shopping cart allows price modification via hidden form field. |
CVE-2000-0254 | Shopping cart allows price modification via hidden form field. |
CVE-2000-0926 | Shopping cart allows price modification via hidden form field. |
CVE-2000-0101 | Shopping cart allows price modification via hidden form field. |
CVE-2000-0102 | Shopping cart allows price modification via hidden form field. |
CVE-2000-0758 | Allows admin access by modifying value of form field. |
CVE-2002-1880 | Read messages by modifying message ID parameter. |
CVE-2000-1234 | Send email to arbitrary users by modifying email parameter. |
CVE-2005-1652 | Authentication bypass by setting a parameter. |
CVE-2005-1784 | Product does not check authorization for configuration change admin script, leading to password theft via modified e-mail address field. |
CVE-2005-2314 | Logic error leads to password disclosure. |
CVE-2005-1682 | Modification of message number parameter allows attackers to read other people's messages. |
Phase: Architecture and Design Assume all input is malicious. Use a standard input validation mechanism to validate all input for length, type, syntax, and business rules before accepting the data to be displayed or stored. Use an "accept known good" validation strategy. Input (specifically, unexpected CRLFs) that is not appropriate should not be processed into HTTP headers. |
Use and specify a strong input/output encoding (such as ISO 8859-1 or UTF 8). |
Do not rely exclusively on blacklist validation to detect malicious input or to encode output. There are too many variants to encode a character; you're likely to miss some variants. |
Inputs should be decoded and canonicalized to the application's current internal representation before being validated. Make sure that your application does not decode the same input twice. Such errors could be used to bypass whitelist schemes by introducing dangerous inputs after they have been checked. |
Nature | Type | ID | Name | View(s) this relationship pertains to![]() |
---|---|---|---|---|
ChildOf | ![]() | 471 | Modification of Assumed-Immutable Data (MAID) | Development Concepts (primary)699 Research Concepts1000 |
ChildOf | ![]() | 642 | External Control of Critical State Data | Research Concepts (primary)1000 |
ChildOf | ![]() | 715 | OWASP Top Ten 2007 Category A4 - Insecure Direct Object Reference | Weaknesses in OWASP Top Ten (2007) (primary)629 |
ChildOf | ![]() | 722 | OWASP Top Ten 2004 Category A1 - Unvalidated Input | Weaknesses in OWASP Top Ten (2004) (primary)711 |
RequiredBy | ![]() | 384 | Session Fixation | Research Concepts1000 |
CanFollow | ![]() | 656 | Reliance on Security through Obscurity | Research Concepts1000 |
This is a primary weakness for many other weaknesses and functional consequences, including XSS, SQL injection, path disclosure, and file inclusion. |
Mapped Taxonomy Name | Node ID | Fit | Mapped Node Name |
---|---|---|---|
PLOVER | Web Parameter Tampering | ||
OWASP Top Ten 2007 | A4 | CWE More Specific | Insecure Direct Object Reference |
OWASP Top Ten 2004 | A1 | CWE More Specific | Unvalidated Input |
Submissions | ||||
---|---|---|---|---|
Submission Date | Submitter | Organization | Source | |
PLOVER | Externally Mined | |||
Modifications | ||||
Modification Date | Modifier | Organization | Source | |
2008-07-01 | Sean Eidemiller | Cigital | External | |
added/updated demonstrative examples | ||||
2008-07-01 | Eric Dalci | Cigital | External | |
updated Potential Mitigations, Time of Introduction | ||||
2008-09-08 | CWE Content Team | MITRE | Internal | |
updated Description, Relationships, Other Notes, Taxonomy Mappings | ||||
2009-01-12 | CWE Content Team | MITRE | Internal | |
updated Relationships | ||||
2009-07-27 | CWE Content Team | MITRE | Internal | |
updated Potential Mitigations | ||||
2009-10-29 | CWE Content Team | MITRE | Internal | |
updated Common Consequences, Demonstrative Examples, Description, Other Notes, Relationship Notes, Theoretical Notes | ||||
Previous Entry Names | ||||
Change Date | Previous Entry Name | |||
2008-04-11 | Web Parameter Tampering | |||