CWE-843 Detail

The product allocates or initializes a resource such as a pointer, object, or variable using one type, but it later accesses that resource using a type that is incompatible with the original type.

When the product accesses the resource using an incompatible type, this could trigger logical errors because the resource does not have expected properties. In languages without memory safety, such as C and C++, type confusion can lead to out-of-bounds memory access.

While this weakness is frequently associated with unions when parsing data with many different embedded object types in C, it can be present in any application that can interpret the same variable or memory location in multiple ways.

This weakness is not unique to C and C++. For example, errors in PHP applications can be triggered by providing array parameters when scalars are expected, or vice versa. Languages such as Perl, which perform automatic conversion of a variable of one type when it is accessed as if it were another type, can also contain these issues.

Modes Of Introduction

Implementation

Applicable Platforms

Language

Name: C (Undetermined)
Name: C++ (Undetermined)

Common Consequences

Observed Examples

Vulnerability Mapping Notes

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

NotesNotes

This weakness is possible in any type-unsafe programming language.

Type confusion weaknesses have received some attention by applied researchers and major software vendors for C and C++ code. Some publicly-reported vulnerabilities probably have type confusion as a root-cause weakness, but these may be described as "memory corruption" instead.

For other languages, there are very few public reports of type confusion weaknesses. These are probably under-studied. Since many programs rely directly or indirectly on loose typing, a potential "type confusion" behavior might be intentional, possibly requiring more manual analysis.

References

REF-811

Attacking Interoperability
Mark Dowd, Ryan Smith, David Dewey.
http://hustlelabs.com/stuff/bh2009_dowd_smith_dewey.pdf

REF-62

The Art of Software Security Assessment
Mark Dowd, John McDonald, Justin Schuh.

Submission

Modifications