Description

The software stores security-critical state information about its users, or the software itself, in a location that is accessible to unauthorized actors.

Extended Description

If an attacker can modify the state information without detection, then it could be used to perform unauthorized actions or access unexpected resources, since the application programmer does not expect that the state can be changed.

State information can be stored in various locations such as a cookie, in a hidden web form field, input parameter or argument, an environment variable, a database record, within a settings file, etc. All of these locations have the potential to be modified by an attacker. When this state information is used to control security or determine resource usage, then it may create a vulnerability. For example, an application may perform authentication, then save the state in an "authenticated=true" cookie. An attacker may simply create this cookie in order to bypass the authentication.

Enabling Factors for Exploitation
An application maintains its own state and/or user state (i.e. application is stateful).
State information can be affected by the user of an application through some means other than the legitimate state transitions (e.g. logging into the system, purchasing an item, making a payment, etc.)
An application does not have means to detect state tampering and behave in a fail safe manner.

Likelihood of Exploit: High

Applicable Platforms
Language Class: All
Technology Class: Often
Technology Class: Web-Server

Time Of Introduction

• Architecture and Design
• Implementation

Related Attack Patterns

• CAPEC-167
• CAPEC-21
• CAPEC-31

Common Consequences

Detection Methods
None

Potential Mitigations

Relationships

Demonstrative Examples   (Details)

1. In the following example, an authentication flag is read from a browser cookie, thus allowing for external control of user state data.
2. The following code segment implements a basic server that uses the "ls" program to perform a directory listing of the directory that is listed in the "HOMEDIR" environment variable. The code intends to allow the user to specify an alternate "LANG" environment variable. This causes "ls" to customize its output based on a given language, which is an important capability when supporting internationalization.
3. The following code uses input from a configuration file to determine which file to open and echo back to the user. If the program runs with privileges and malicious users can change the configuration file, they can use the program to read any file on the system that ends with the extension .txt. (Demonstrative Example Id DX-66)
4. The following code uses input from an HTTP request to create a file name. The programmer has not considered the possibility that an attacker could provide a file name such as "../../tomcat/conf/server.xml", which causes the application to delete one of its own configuration files (CWE-22). (Demonstrative Example Id DX-65)
5. This code prints all of the running processes belonging to the current user. (Demonstrative Example Id DX-68)
6. This program is intended to execute a command that lists the contents of a restricted directory, then performs other actions. Assume that it runs with setuid privileges in order to bypass the permissions check by the operating system. (Demonstrative Example Id DX-67)

Observed Examples

1. CVE-2005-2428 : Mail client stores password hashes for unrelated accounts in a hidden form field.
2. CVE-2008-0306 : Privileged program trusts user-specified environment variable to modify critical configuration settings.
3. CVE-1999-0073 : Telnet daemon allows remote clients to specify critical environment variables for the server, leading to code execution.
4. CVE-2007-4432 : Untrusted search path vulnerability through modified LD_LIBRARY_PATH environment variable.
5. CVE-2006-7191 : Untrusted search path vulnerability through modified LD_LIBRARY_PATH environment variable.
6. CVE-2008-5738 : Calendar application allows bypass of authentication by setting a certain cookie value to 1.
7. CVE-2008-5642 : Setting of a language preference in a cookie enables path traversal attack.
8. CVE-2008-5125 : Application allows admin privileges by setting a cookie value to "admin."
9. CVE-2008-5065 : Application allows admin privileges by setting a cookie value to "admin."
10. CVE-2008-4752 : Application allows admin privileges by setting a cookie value to "admin."
11. CVE-2000-0102 : Shopping cart allows price modification via hidden form field.
12. CVE-2000-0253 : Shopping cart allows price modification via hidden form field.
13. CVE-2008-1319 : Server allows client to specify the search path, which can be modified to point to a program that the client has uploaded.

White Box Definitions
None

Black Box Definitions
None

Taxynomy Mappings
None

References:

1. OWASP .Top 10 2007-Insecure Direct Object Reference. Published on 2007.
2. .HMAC. Wikipedia. 2011-08-18.
3. Michael Howard David LeBlanc John Viega .24 Deadly Sins of Software Security. McGraw-Hill. Section:'"Sin 4: Use of Magic URLs, Predictable Cookies, and Hidden Form Fields." Page 75'. Published on 2010.