CWE

Common Weakness Enumeration

A Community-Developed Dictionary of Software Weakness Types

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CWE-20: Improper Input Validation

 
Improper Input Validation
Weakness ID: 20 (Weakness Class)Status: Usable
+ Description

Description Summary

The product does not validate or incorrectly validates input that can affect the control flow or data flow of a program.

Extended Description

When software does not validate input properly, an attacker is able to craft the input in a form that is not expected by the rest of the application. This will lead to parts of the system receiving unintended input, which may result in altered control flow, arbitrary control of a resource, or arbitrary code execution.

+ Terminology Notes

The "input validation" term is extremely common, but it is used in many different ways. In some cases its usage can obscure the real underlying weakness or otherwise hide chaining and composite relationships.

Some people use "input validation" as a general term that covers many different neutralization techniques for ensuring that input is appropriate, such as filtering, canonicalization, and escaping. Others use the term in a more narrow context to simply mean "checking if an input conforms to expectations without changing it."

+ Time of Introduction
  • Architecture and Design
  • Implementation
+ Applicable Platforms

Languages

Language-independent

Platform Notes

Input validation can be a problem in any system that receives data from an external source.

+ Modes of Introduction

If a programmer believes that an attacker cannot modify certain inputs, then the programmer might not perform any input validation at all. For example, in web applications, many programmers believe that cookies and hidden form fields can not be modified from a web browser (CWE-472), although they can be altered using a proxy or a custom program. In a client-server architecture, the programmer might assume that client-side security checks cannot be bypassed, even when a custom client could be written that skips those checks (CWE-602).

+ Common Consequences
ScopeEffect

Technical Impact: DoS: crash / exit / restart; DoS: resource consumption (CPU); DoS: resource consumption (memory)

An attacker could provide unexpected values and cause a program crash or excessive consumption of resources, such as memory and CPU.

Technical Impact: Read memory; Read files or directories

An attacker could read confidential data if they are able to control resource references.

Technical Impact: Modify memory; Execute unauthorized code or commands

An attacker could use malicious input to modify data or possibly alter control flow in unexpected ways, including arbitrary command execution.

+ Likelihood of Exploit

High

+ Detection Methods

Automated Static Analysis

Some instances of improper input validation can be detected using automated static analysis.

A static analysis tool might allow the user to specify which application-specific methods or functions perform input validation; the tool might also have built-in knowledge of validation frameworks such as Struts. The tool may then suppress or de-prioritize any associated warnings. This allows the analyst to focus on areas of the software in which input validation does not appear to be present.

Except in the cases described in the previous paragraph, automated static analysis might not be able to recognize when proper input validation is being performed, leading to false positives - i.e., warnings that do not have any security consequences or require any code changes.

Manual Static Analysis

When custom input validation is required, such as when enforcing business rules, manual analysis is necessary to ensure that the validation is properly implemented.

Fuzzing

Fuzzing techniques can be useful for detecting input validation errors. When unexpected inputs are provided to the software, the software should not crash or otherwise become unstable, and it should generate application-controlled error messages. If exceptions or interpreter-generated error messages occur, this indicates that the input was not detected and handled within the application logic itself.

+ Demonstrative Examples

Example 1

This example demonstrates a shopping interaction in which the user is free to specify the quantity of items to be purchased and a total is calculated.

(Bad Code)
Example Language: Java 
...
public static final double price = 20.00;
int quantity = currentUser.getAttribute("quantity");
double total = price * quantity;
chargeUser(total);
...

The user has no control over the price variable, however the code does not prevent a negative value from being specified for quantity. If an attacker were to provide a negative value, then the user would have their account credited instead of debited.

Example 2

This example asks the user for a height and width of an m X n game board with a maximum dimension of 100 squares.

(Bad Code)
Example Language:
...
#define MAX_DIM 100
...
/* board dimensions */
int m,n, error;
board_square_t *board;
printf("Please specify the board height: \n");
error = scanf("%d", &m);
if ( EOF == error ){
die("No integer passed: Die evil hacker!\n");
}
printf("Please specify the board width: \n");
error = scanf("%d", &n);
if ( EOF == error ){
die("No integer passed: Die evil hacker!\n");
}
if ( m > MAX_DIM || n > MAX_DIM ) {
die("Value too large: Die evil hacker!\n");
}
board = (board_square_t*) malloc( m * n * sizeof(board_square_t));
...

While this code checks to make sure the user cannot specify large, positive integers and consume too much memory, it does not check for negative values supplied by the user. As a result, an attacker can perform a resource consumption (CWE-400) attack against this program by specifying two, large negative values that will not overflow, resulting in a very large memory allocation (CWE-789) and possibly a system crash. Alternatively, an attacker can provide very large negative values which will cause an integer overflow (CWE-190) and unexpected behavior will follow depending on how the values are treated in the remainder of the program.

Example 3

The following example shows a PHP application in which the programmer attempts to display a user's birthday and homepage.

(Bad Code)
Example Language: PHP 
$birthday = $_GET['birthday'];
$homepage = $_GET['homepage'];
echo "Birthday: $birthday<br>Homepage: <a href=$homepage>click here</a>"

The programmer intended for $birthday to be in a date format and $homepage to be a valid URL. However, since the values are derived from an HTTP request, if an attacker can trick a victim into clicking a crafted URL with <script> tags providing the values for birthday and / or homepage, then the script will run on the client's browser when the web server echoes the content. Notice that even if the programmer were to defend the $birthday variable by restricting input to integers and dashes, it would still be possible for an attacker to provide a string of the form:

(Attack)
 
2009-01-09--

If this data were used in a SQL statement, it would treat the remainder of the statement as a comment. The comment could disable other security-related logic in the statement. In this case, encoding combined with input validation would be a more useful protection mechanism.

Furthermore, an XSS (CWE-79) attack or SQL injection (CWE-89) are just a few of the potential consequences when input validation is not used. Depending on the context of the code, CRLF Injection (CWE-93), Argument Injection (CWE-88), or Command Injection (CWE-77) may also be possible.

Example 4

This function attempts to extract a pair of numbers from a user-supplied string.

(Bad Code)
Example Language:
void parse_data(char *untrusted_input){
int m, n, error;
error = sscanf(untrusted_input, "%d:%d", &m, &n);
if ( EOF == error ){
die("Did not specify integer value. Die evil hacker!\n");
}
/* proceed assuming n and m are initialized correctly */
}

This code attempts to extract two integer values out of a formatted, user-supplied input. However, if an attacker were to provide an input of the form:

(Attack)
 
123:

then only the m variable will be initialized. Subsequent use of n may result in the use of an uninitialized variable (CWE-457).

Example 5

The following example takes a user-supplied value to allocate an array of objects and then operates on the array.

(Bad Code)
Example Language: Java 
private void buildList ( int untrustedListSize ){
if ( 0 > untrustedListSize ){
die("Negative value supplied for list size, die evil hacker!");
}
Widget[] list = new Widget [ untrustedListSize ];
list[0] = new Widget();
}

This example attempts to build a list from a user-specified value, and even checks to ensure a non-negative value is supplied. If, however, a 0 value is provided, the code will build an array of size 0 and then try to store a new Widget in the first location, causing an exception to be thrown.

Example 6

This application has registered to handle a URL when sent an intent:

(Bad Code)
Example Language: Java 
...
IntentFilter filter = new IntentFilter("com.example.URLHandler.openURL");
MyReceiver receiver = new MyReceiver();
registerReceiver(receiver, filter);
...
public class UrlHandlerReceiver extends BroadcastReceiver {
@Override
public void onReceive(Context context, Intent intent) {
if("com.example.URLHandler.openURL".equals(intent.getAction())) {
String URL = intent.getStringExtra("URLToOpen");
int length = URL.length();
...
}
}
}

The application assumes the URL will always be included in the intent. When the URL is not present, the call to getStringExtra() will return null, thus causing a null pointer exception when length() is called.

+ Observed Examples
ReferenceDescription
Eval injection in Perl program using an ID that should only contain hyphens and numbers.
SQL injection through an ID that was supposed to be numeric.
lack of input validation in spreadsheet program leads to buffer overflows, integer overflows, array index errors, and memory corruption.
insufficient validation enables XSS
driver in security product allows code execution due to insufficient validation
infinite loop from DNS packet with a label that points to itself
infinite loop from DNS packet with a label that points to itself
missing parameter leads to crash
HTTP request with missing protocol version number leads to crash
request with missing parameters leads to information exposure
system crash with offset value that is inconsistent with packet size
size field that is inconsistent with packet size leads to buffer over-read
product uses a blacklist to identify potentially dangerous content, allowing attacker to bypass a warning
security bypass via an extra header
use of extra data in a signature allows certificate signature forging
empty packet triggers reboot
incomplete blacklist allows SQL injection
NUL byte in theme name cause directory traversal impact to be worse
kernel does not validate an incoming pointer before dereferencing it
anti-virus product has insufficient input validation of hooked SSDT functions, allowing code execution
anti-virus product allows DoS via zero-length field
driver does not validate input from userland to the kernel
kernel does not validate parameters sent in from userland, allowing code execution
lack of validation of string length fields allows memory consumption or buffer over-read
lack of validation of length field leads to infinite loop
lack of validation of input to an IOCTL allows code execution
zero-length attachment causes crash
zero-length input causes free of uninitialized pointer
crash via a malformed frame structure
infinite loop from a long SMTP request
router crashes with a malformed packet
packet with invalid version number leads to NULL pointer dereference
crash via multiple "." characters in file extension
+ Potential Mitigations

Phase: Architecture and Design

Strategies: Input Validation; Libraries or Frameworks

Use an input validation framework such as Struts or the OWASP ESAPI Validation API. If you use Struts, be mindful of weaknesses covered by the CWE-101 category.

Phases: Architecture and Design; Implementation

Strategy: Identify and Reduce Attack Surface

Understand all the potential areas where untrusted inputs can enter your software: parameters or arguments, cookies, anything read from the network, environment variables, reverse DNS lookups, query results, request headers, URL components, e-mail, files, filenames, databases, and any external systems that provide data to the application. Remember that such inputs may be obtained indirectly through API calls.

Phase: Implementation

Strategy: Input Validation

Assume all input is malicious. Use an "accept known good" input validation strategy, i.e., use a whitelist of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does.

When performing input validation, consider all potentially relevant properties, including length, type of input, the full range of acceptable values, missing or extra inputs, syntax, consistency across related fields, and conformance to business rules. As an example of business rule logic, "boat" may be syntactically valid because it only contains alphanumeric characters, but it is not valid if the input is only expected to contain colors such as "red" or "blue."

Do not rely exclusively on looking for malicious or malformed inputs (i.e., do not rely on a blacklist). A blacklist is likely to miss at least one undesirable input, especially if the code's environment changes. This can give attackers enough room to bypass the intended validation. However, blacklists can be useful for detecting potential attacks or determining which inputs are so malformed that they should be rejected outright.

Phase: Architecture and Design

For any security checks that are performed on the client side, ensure that these checks are duplicated on the server side, in order to avoid CWE-602. Attackers can bypass the client-side checks by modifying values after the checks have been performed, or by changing the client to remove the client-side checks entirely. Then, these modified values would be submitted to the server.

Even though client-side checks provide minimal benefits with respect to server-side security, they are still useful. First, they can support intrusion detection. If the server receives input that should have been rejected by the client, then it may be an indication of an attack. Second, client-side error-checking can provide helpful feedback to the user about the expectations for valid input. Third, there may be a reduction in server-side processing time for accidental input errors, although this is typically a small savings.

Phase: Implementation

When your application combines data from multiple sources, perform the validation after the sources have been combined. The individual data elements may pass the validation step but violate the intended restrictions after they have been combined.

Phase: Implementation

Be especially careful to validate all input when invoking code that crosses language boundaries, such as from an interpreted language to native code. This could create an unexpected interaction between the language boundaries. Ensure that you are not violating any of the expectations of the language with which you are interfacing. For example, even though Java may not be susceptible to buffer overflows, providing a large argument in a call to native code might trigger an overflow.

Phase: Implementation

Directly convert your input type into the expected data type, such as using a conversion function that translates a string into a number. After converting to the expected data type, ensure that the input's values fall within the expected range of allowable values and that multi-field consistencies are maintained.

Phase: Implementation

Inputs should be decoded and canonicalized to the application's current internal representation before being validated (CWE-180, CWE-181). Make sure that your application does not inadvertently decode the same input twice (CWE-174). Such errors could be used to bypass whitelist schemes by introducing dangerous inputs after they have been checked. Use libraries such as the OWASP ESAPI Canonicalization control.

Consider performing repeated canonicalization until your input does not change any more. This will avoid double-decoding and similar scenarios, but it might inadvertently modify inputs that are allowed to contain properly-encoded dangerous content.

Phase: Implementation

When exchanging data between components, ensure that both components are using the same character encoding. Ensure that the proper encoding is applied at each interface. Explicitly set the encoding you are using whenever the protocol allows you to do so.

Phase: Testing

Use automated static analysis tools that target this type of weakness. Many modern techniques use data flow analysis to minimize the number of false positives. This is not a perfect solution, since 100% accuracy and coverage are not feasible.

Phase: Testing

Use dynamic tools and techniques that interact with the software using large test suites with many diverse inputs, such as fuzz testing (fuzzing), robustness testing, and fault injection. The software's operation may slow down, but it should not become unstable, crash, or generate incorrect results.

+ Relationships
NatureTypeIDNameView(s) this relationship pertains toView(s)
ChildOfCategoryCategory19Data Handling
Development Concepts (primary)699
ChildOfWeakness ClassWeakness Class693Protection Mechanism Failure
Research Concepts (primary)1000
ChildOfCategoryCategory722OWASP Top Ten 2004 Category A1 - Unvalidated Input
Weaknesses in OWASP Top Ten (2004) (primary)711
ChildOfCategoryCategory738CERT C Secure Coding Section 04 - Integers (INT)
Weaknesses Addressed by the CERT C Secure Coding Standard (primary)734
ChildOfCategoryCategory742CERT C Secure Coding Section 08 - Memory Management (MEM)
Weaknesses Addressed by the CERT C Secure Coding Standard734
ChildOfCategoryCategory746CERT C Secure Coding Section 12 - Error Handling (ERR)
Weaknesses Addressed by the CERT C Secure Coding Standard734
ChildOfCategoryCategory747CERT C Secure Coding Section 49 - Miscellaneous (MSC)
Weaknesses Addressed by the CERT C Secure Coding Standard734
ChildOfCategoryCategory7512009 Top 25 - Insecure Interaction Between Components
Weaknesses in the 2009 CWE/SANS Top 25 Most Dangerous Programming Errors (primary)750
ChildOfCategoryCategory872CERT C++ Secure Coding Section 04 - Integers (INT)
Weaknesses Addressed by the CERT C++ Secure Coding Standard868
ChildOfCategoryCategory876CERT C++ Secure Coding Section 08 - Memory Management (MEM)
Weaknesses Addressed by the CERT C++ Secure Coding Standard868
ChildOfCategoryCategory883CERT C++ Secure Coding Section 49 - Miscellaneous (MSC)
Weaknesses Addressed by the CERT C++ Secure Coding Standard (primary)868
ChildOfCategoryCategory896SFP Cluster: Tainted Input
Software Fault Pattern (SFP) Clusters (primary)888
CanPrecedeWeakness ClassWeakness Class22Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')
Research Concepts1000
CanPrecedeWeakness BaseWeakness Base41Improper Resolution of Path Equivalence
Research Concepts1000
CanPrecedeWeakness ClassWeakness Class74Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection')
Research Concepts1000
ParentOfWeakness BaseWeakness Base15External Control of System or Configuration Setting
Seven Pernicious Kingdoms (primary)700
ParentOfCategoryCategory21Pathname Traversal and Equivalence Errors
Development Concepts (primary)699
ParentOfWeakness ClassWeakness Class73External Control of File Name or Path
Development Concepts (primary)699
Seven Pernicious Kingdoms (primary)700
ParentOfWeakness ClassWeakness Class77Improper Neutralization of Special Elements used in a Command ('Command Injection')
Seven Pernicious Kingdoms (primary)700
ParentOfWeakness BaseWeakness Base79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
Seven Pernicious Kingdoms (primary)700
ParentOfWeakness BaseWeakness Base89Improper Neutralization of Special Elements used in an SQL Command ('SQL Injection')
Seven Pernicious Kingdoms (primary)700
ParentOfWeakness BaseWeakness Base99Improper Control of Resource Identifiers ('Resource Injection')
Seven Pernicious Kingdoms (primary)700
ParentOfCategoryCategory100Technology-Specific Input Validation Problems
Development Concepts (primary)699
ParentOfWeakness VariantWeakness Variant102Struts: Duplicate Validation Forms
Seven Pernicious Kingdoms (primary)700
ParentOfWeakness VariantWeakness Variant103Struts: Incomplete validate() Method Definition
Seven Pernicious Kingdoms (primary)700
ParentOfWeakness VariantWeakness Variant104Struts: Form Bean Does Not Extend Validation Class
Seven Pernicious Kingdoms (primary)700
ParentOfWeakness VariantWeakness Variant105Struts: Form Field Without Validator
Seven Pernicious Kingdoms (primary)700
Research Concepts (primary)1000
ParentOfWeakness VariantWeakness Variant106Struts: Plug-in Framework not in Use
Seven Pernicious Kingdoms (primary)700
Research Concepts (primary)1000
ParentOfWeakness VariantWeakness Variant107Struts: Unused Validation Form
Seven Pernicious Kingdoms (primary)700
ParentOfWeakness VariantWeakness Variant108Struts: Unvalidated Action Form
Seven Pernicious Kingdoms (primary)700
Research Concepts (primary)1000
ParentOfWeakness VariantWeakness Variant109Struts: Validator Turned Off
Seven Pernicious Kingdoms (primary)700
Research Concepts (primary)1000
ParentOfWeakness VariantWeakness Variant110Struts: Validator Without Form Field
Seven Pernicious Kingdoms (primary)700
ParentOfWeakness BaseWeakness Base111Direct Use of Unsafe JNI
Development Concepts (primary)699
Seven Pernicious Kingdoms (primary)700
ParentOfWeakness BaseWeakness Base112Missing XML Validation
Development Concepts (primary)699
Seven Pernicious Kingdoms (primary)700
Research Concepts (primary)1000
ParentOfWeakness BaseWeakness Base113Improper Neutralization of CRLF Sequences in HTTP Headers ('HTTP Response Splitting')
Seven Pernicious Kingdoms (primary)700
ParentOfWeakness BaseWeakness Base114Process Control
Development Concepts (primary)699
Seven Pernicious Kingdoms (primary)700
Research Concepts (primary)1000
ParentOfWeakness BaseWeakness Base117Improper Output Neutralization for Logs
Seven Pernicious Kingdoms (primary)700
ParentOfWeakness ClassWeakness Class119Improper Restriction of Operations within the Bounds of a Memory Buffer
Development Concepts699
Seven Pernicious Kingdoms (primary)700
ParentOfWeakness BaseWeakness Base120Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')
Seven Pernicious Kingdoms (primary)700
ParentOfWeakness BaseWeakness Base129Improper Validation of Array Index
Development Concepts (primary)699
Research Concepts (primary)1000
ParentOfWeakness BaseWeakness Base134Uncontrolled Format String
Seven Pernicious Kingdoms (primary)700
ParentOfWeakness BaseWeakness Base170Improper Null Termination
Seven Pernicious Kingdoms (primary)700
ParentOfWeakness BaseWeakness Base190Integer Overflow or Wraparound
Seven Pernicious Kingdoms (primary)700
ParentOfWeakness BaseWeakness Base466Return of Pointer Value Outside of Expected Range
Seven Pernicious Kingdoms (primary)700
ParentOfWeakness BaseWeakness Base470Use of Externally-Controlled Input to Select Classes or Code ('Unsafe Reflection')
Development Concepts (primary)699
Seven Pernicious Kingdoms (primary)700
ParentOfWeakness VariantWeakness Variant554ASP.NET Misconfiguration: Not Using Input Validation Framework
Development Concepts (primary)699
Research Concepts (primary)1000
ParentOfWeakness VariantWeakness Variant601URL Redirection to Untrusted Site ('Open Redirect')
Development Concepts (primary)699
ParentOfWeakness BaseWeakness Base606Unchecked Input for Loop Condition
Development Concepts (primary)699
Research Concepts (primary)1000
ParentOfWeakness VariantWeakness Variant622Improper Validation of Function Hook Arguments
Development Concepts (primary)699
Research Concepts (primary)1000
ParentOfWeakness VariantWeakness Variant626Null Byte Interaction Error (Poison Null Byte)
Development Concepts (primary)699
Research Concepts (primary)1000
ParentOfCompound Element: ChainCompound Element: Chain680Integer Overflow to Buffer Overflow
Research Concepts (primary)1000
ParentOfCompound Element: ChainCompound Element: Chain690Unchecked Return Value to NULL Pointer Dereference
Research Concepts (primary)1000
ParentOfCompound Element: ChainCompound Element: Chain692Incomplete Blacklist to Cross-Site Scripting
Research Concepts (primary)1000
ParentOfWeakness VariantWeakness Variant781Improper Address Validation in IOCTL with METHOD_NEITHER I/O Control Code
Development Concepts (primary)699
Research Concepts (primary)1000
ParentOfWeakness VariantWeakness Variant785Use of Path Manipulation Function without Maximum-sized Buffer
Development Concepts699
Seven Pernicious Kingdoms (primary)700
ParentOfWeakness VariantWeakness Variant789Uncontrolled Memory Allocation
Research Concepts1000
MemberOfViewView635Weaknesses Used by NVD
Weaknesses Used by NVD (primary)635
MemberOfViewView700Seven Pernicious Kingdoms
Seven Pernicious Kingdoms (primary)700
+ Relationship Notes

CWE-116 and CWE-20 have a close association because, depending on the nature of the structured message, proper input validation can indirectly prevent special characters from changing the meaning of a structured message. For example, by validating that a numeric ID field should only contain the 0-9 characters, the programmer effectively prevents injection attacks.

However, input validation is not always sufficient, especially when less stringent data types must be supported, such as free-form text. Consider a SQL injection scenario in which a last name is inserted into a query. The name "O'Reilly" would likely pass the validation step since it is a common last name in the English language. However, it cannot be directly inserted into the database because it contains the "'" apostrophe character, which would need to be escaped or otherwise neutralized. In this case, stripping the apostrophe might reduce the risk of SQL injection, but it would produce incorrect behavior because the wrong name would be recorded.

+ Research Gaps

There is not much research into the classification of input validation techniques and their application. Many publicly-disclosed vulnerabilities simply characterize a problem as "input validation" without providing more specific details that might contribute to a deeper understanding of validation techniques and the weaknesses they can prevent or reduce. Validation is over-emphasized in contrast to other neutralization techniques such as filtering and enforcement by conversion. See the vulnerability theory paper.

+ Taxonomy Mappings
Mapped Taxonomy NameNode IDFitMapped Node Name
7 Pernicious KingdomsInput validation and representation
OWASP Top Ten 2004A1Unvalidated Input
CERT C Secure CodingERR07-CPrefer functions that support error checking over equivalent functions that don't
CERT C Secure CodingINT06-CUse strtol() or a related function to convert a string token to an integer
CERT C Secure CodingMEM10-CDefine and use a pointer validation function
CERT C Secure CodingMSC08-CLibrary functions should validate their parameters
WASC20Improper Input Handling
CERT C++ Secure CodingINT06-CPPUse strtol() or a related function to convert a string token to an integer
CERT C++ Secure CodingMEM10-CPPDefine and use a pointer validation function
CERT C++ Secure CodingMSC08-CPPFunctions should validate their parameters
+ References
Jim Manico. "Input Validation with ESAPI - Very Important". 2008-08-15. <http://manicode.blogspot.com/2008/08/input-validation-with-esapi.html>.
[REF-21] OWASP. "OWASP Enterprise Security API (ESAPI) Project". <http://www.owasp.org/index.php/ESAPI>.
Joel Scambray, Mike Shema and Caleb Sima. "Hacking Exposed Web Applications, Second Edition". Input Validation Attacks. McGraw-Hill. 2006-06-05.
Jeremiah Grossman. "Input validation or output filtering, which is better?". 2007-01-30. <http://jeremiahgrossman.blogspot.com/2007/01/input-validation-or-output-filtering.html>.
Kevin Beaver. "The importance of input validation". 2006-09-06. <http://searchsoftwarequality.techtarget.com/tip/0,289483,sid92_gci1214373,00.html>.
[REF-11] M. Howard and D. LeBlanc. "Writing Secure Code". Chapter 10, "All Input Is Evil!" Page 341. 2nd Edition. Microsoft. 2002.
+ Maintenance Notes

Input validation - whether missing or incorrect - is such an essential and widespread part of secure development that it is implicit in many different weaknesses. Traditionally, problems such as buffer overflows and XSS have been classified as input validation problems by many security professionals. However, input validation is not necessarily the only protection mechanism available for avoiding such problems, and in some cases it is not even sufficient. The CWE team has begun capturing these subtleties in chains within the Research Concepts view (CWE-1000), but more work is needed.

+ Content History
Submissions
Submission DateSubmitterOrganizationSource
Externally Mined
Modifications
Modification DateModifierOrganizationSource
2008-07-01CigitalExternal
updated Potential_Mitigations, Time_of_Introduction
2008-08-15VeracodeExternal
Suggested OWASP Top Ten 2004 mapping
2008-09-08MITREInternal
updated Relationships, Other_Notes, Taxonomy_Mappings
2008-11-24MITREInternal
updated Relationships, Taxonomy_Mappings
2009-01-12MITREInternal
updated Applicable_Platforms, Common_Consequences, Demonstrative_Examples, Description, Likelihood_of_Exploit, Name, Observed_Examples, Other_Notes, Potential_Mitigations, References, Relationship_Notes, Relationships
2009-03-10MITREInternal
updated Description, Potential_Mitigations
2009-05-27MITREInternal
updated Related_Attack_Patterns
2009-07-27MITREInternal
updated Relationships
2009-10-29MITREInternal
updated Common_Consequences, Demonstrative_Examples, Maintenance_Notes, Modes_of_Introduction, Observed_Examples, Relationships, Research_Gaps, Terminology_Notes
2009-12-28MITREInternal
updated Applicable_Platforms, Demonstrative_Examples, Detection_Factors
2010-02-16MITREInternal
updated Detection_Factors, Potential_Mitigations, References, Taxonomy_Mappings
2010-04-05MITREInternal
updated Related_Attack_Patterns
2010-06-21MITREInternal
updated Potential_Mitigations, Research_Gaps, Terminology_Notes
2010-09-27MITREInternal
updated Potential_Mitigations, Relationships
2010-12-13MITREInternal
updated Demonstrative_Examples, Description
2011-03-29MITREInternal
updated Observed_Examples
2011-06-01MITREInternal
updated Applicable_Platforms, Common_Consequences, Relationship_Notes
2011-09-13MITREInternal
updated Relationships, Taxonomy_Mappings
2012-05-11MITREInternal
updated Demonstrative_Examples, References, Related_Attack_Patterns, Relationships
2012-10-30MITREInternal
updated Potential_Mitigations
2013-02-21MITREInternal
updated Relationships
2013-07-17MITREInternal
updated Relationships
2014-02-18MITREInternal
updated Demonstrative_Examples, Related_Attack_Patterns
Previous Entry Names
Change DatePrevious Entry Name
2009-01-12Insufficient Input Validation
Page Last Updated: June 23, 2014