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Home > CWE List > CWE-482: Comparing instead of Assigning (4.16)  
ID

CWE-482: Comparing instead of Assigning

Weakness ID: 482
Vulnerability Mapping: ALLOWED This CWE ID may be used to map to real-world vulnerabilities
Abstraction: Variant Variant - a weakness that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource.
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+ Description
The code uses an operator for comparison when the intention was to perform an assignment.
+ Extended Description
In many languages, the compare statement is very close in appearance to the assignment statement; they are often confused.
+ Common Consequences
Section HelpThis table specifies different individual consequences associated with the weakness. The Scope identifies the application security area that is violated, while the Impact describes the negative technical impact that arises if an adversary succeeds in exploiting this weakness. The Likelihood provides information about how likely the specific consequence is expected to be seen relative to the other consequences in the list. For example, there may be high likelihood that a weakness will be exploited to achieve a certain impact, but a low likelihood that it will be exploited to achieve a different impact.
Scope Impact Likelihood
Availability
Integrity

Technical Impact: Unexpected State

The assignment will not take place, which should cause obvious program execution problems.
+ Potential Mitigations

Phase: Testing

Many IDEs and static analysis products will detect this problem.
+ Relationships
Section Help This table shows the weaknesses and high level categories that are related to this weakness. These relationships are defined as ChildOf, ParentOf, MemberOf and give insight to similar items that may exist at higher and lower levels of abstraction. In addition, relationships such as PeerOf and CanAlsoBe are defined to show similar weaknesses that the user may want to explore.
+ Relevant to the view "Research Concepts" (CWE-1000)
Nature Type ID Name
ChildOf Base Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource. 480 Use of Incorrect Operator
+ Modes Of Introduction
Section HelpThe different Modes of Introduction provide information about how and when this weakness may be introduced. The Phase identifies a point in the life cycle at which introduction may occur, while the Note provides a typical scenario related to introduction during the given phase.
Phase Note
Implementation This bug primarily originates from a typo.
+ Applicable Platforms
Section HelpThis listing shows possible areas for which the given weakness could appear. These may be for specific named Languages, Operating Systems, Architectures, Paradigms, Technologies, or a class of such platforms. The platform is listed along with how frequently the given weakness appears for that instance.

Languages

C (Undetermined Prevalence)

C++ (Undetermined Prevalence)

+ Likelihood Of Exploit
Low
+ Demonstrative Examples

Example 1

The following example demonstrates the weakness.

(bad code)
Example Language: Java 
void called(int foo) {
foo==1;
if (foo==1) System.out.println("foo\n");
}
int main() {

called(2);
return 0;
}

Example 2

The following C/C++ example shows a simple implementation of a stack that includes methods for adding and removing integer values from the stack. The example uses pointers to add and remove integer values to the stack array variable.

(bad code)
Example Language:
#define SIZE 50
int *tos, *p1, stack[SIZE];

void push(int i) {
p1++;
if(p1==(tos+SIZE)) {

// Print stack overflow error message and exit
}
*p1 == i;
}

int pop(void) {
if(p1==tos) {

// Print stack underflow error message and exit
}
p1--;
return *(p1+1);
}

int main(int argc, char *argv[]) {

// initialize tos and p1 to point to the top of stack
tos = stack;
p1 = stack;
// code to add and remove items from stack
...
return 0;
}

The push method includes an expression to assign the integer value to the location in the stack pointed to by the pointer variable.

However, this expression uses the comparison operator "==" rather than the assignment operator "=". The result of using the comparison operator instead of the assignment operator causes erroneous values to be entered into the stack and can cause unexpected results.


+ Detection Methods

Automated Static Analysis

Automated static analysis, commonly referred to as Static Application Security Testing (SAST), can find some instances of this weakness by analyzing source code (or binary/compiled code) without having to execute it. Typically, this is done by building a model of data flow and control flow, then searching for potentially-vulnerable patterns that connect "sources" (origins of input) with "sinks" (destinations where the data interacts with external components, a lower layer such as the OS, etc.)

Effectiveness: High

+ Memberships
Section HelpThis MemberOf Relationships table shows additional CWE Categories and Views that reference this weakness as a member. This information is often useful in understanding where a weakness fits within the context of external information sources.
Nature Type ID Name
MemberOf CategoryCategory - a CWE entry that contains a set of other entries that share a common characteristic. 747 CERT C Secure Coding Standard (2008) Chapter 14 - Miscellaneous (MSC)
MemberOf CategoryCategory - a CWE entry that contains a set of other entries that share a common characteristic. 883 CERT C++ Secure Coding Section 49 - Miscellaneous (MSC)
MemberOf CategoryCategory - a CWE entry that contains a set of other entries that share a common characteristic. 886 SFP Primary Cluster: Unused entities
MemberOf CategoryCategory - a CWE entry that contains a set of other entries that share a common characteristic. 1410 Comprehensive Categorization: Insufficient Control Flow Management
+ Vulnerability Mapping Notes

Usage: ALLOWED

(this CWE ID may be used to map to real-world vulnerabilities)

Reason: Acceptable-Use

Rationale:

This CWE entry is at the Variant level of abstraction, which is a preferred level of abstraction for mapping to the root causes of vulnerabilities.

Comments:

Carefully read both the name and description to ensure that this mapping is an appropriate fit. Do not try to 'force' a mapping to a lower-level Base/Variant simply to comply with this preferred level of abstraction.
+ Taxonomy Mappings
Mapped Taxonomy Name Node ID Fit Mapped Node Name
CLASP Comparing instead of assigning
Software Fault Patterns SFP2 Unused Entities
+ References
[REF-18] Secure Software, Inc.. "The CLASP Application Security Process". 2005. <https://cwe.mitre.org/documents/sources/TheCLASPApplicationSecurityProcess.pdf>. URL validated: 2024-11-17.
[REF-62] Mark Dowd, John McDonald and Justin Schuh. "The Art of Software Security Assessment". Chapter 6, "Typos", Page 289. 1st Edition. Addison Wesley. 2006.
+ Content History
+ Submissions
Submission Date Submitter Organization
2006-07-19
(CWE Draft 3, 2006-07-19)
CLASP
+ Modifications
Modification Date Modifier Organization
2008-07-01 Eric Dalci Cigital
updated Time_of_Introduction
2008-09-08 CWE Content Team MITRE
updated Applicable_Platforms, Description, Relationships, Other_Notes, Taxonomy_Mappings
2008-11-24 CWE Content Team MITRE
updated Relationships, Taxonomy_Mappings
2009-07-27 CWE Content Team MITRE
updated Common_Consequences, Modes_of_Introduction
2009-10-29 CWE Content Team MITRE
updated Other_Notes
2011-06-01 CWE Content Team MITRE
updated Common_Consequences
2011-06-27 CWE Content Team MITRE
updated Common_Consequences
2011-09-13 CWE Content Team MITRE
updated Relationships, Taxonomy_Mappings
2012-05-11 CWE Content Team MITRE
updated References, Relationships
2012-10-30 CWE Content Team MITRE
updated Demonstrative_Examples, Potential_Mitigations
2014-07-30 CWE Content Team MITRE
updated Taxonomy_Mappings
2017-01-19 CWE Content Team MITRE
updated Relationships
2017-11-08 CWE Content Team MITRE
updated Demonstrative_Examples, Taxonomy_Mappings
2020-02-24 CWE Content Team MITRE
updated References, Relationships
2023-04-27 CWE Content Team MITRE
updated Detection_Factors, Relationships
2023-06-29 CWE Content Team MITRE
updated Mapping_Notes
Page Last Updated: November 19, 2024