CWE-783
Operator Precedence Logic Error
Niedrig
Draft
2009-07-27
00h00 +00:00
00h00 +00:00
2025-12-11
00h00 +00:00
00h00 +00:00
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Name: Operator Precedence Logic Error
The product uses an expression in which operator precedence causes incorrect logic to be used.
CWE-Beschreibung
While often just a bug, operator precedence logic errors can have serious consequences if they are used in security-critical code, such as making an authentication decision.
Allgemeine Informationen
Einführungsmodi
Implementation : Logic errors related to operator precedence may cause problems even during normal operation, so they are probably discovered quickly during the testing phase. If testing is incomplete or there is a strong reliance on manual review of the code, then these errors may not be discovered before the software is deployed.Anwendbare Plattformen
Sprache
Name: C (Rarely)Name: C++ (Rarely)
Class: Not Language-Specific (Rarely)
Häufige Konsequenzen
| Bereich | Auswirkung | Wahrscheinlichkeit |
|---|---|---|
| Confidentiality Integrity Availability | Varies by Context, Unexpected State Note: The consequences will vary based on the context surrounding the incorrect precedence. In a security decision, integrity or confidentiality are the most likely results. Otherwise, a crash may occur due to the software reaching an unexpected state. |
Beobachtete Beispiele
| Referenzen | Beschreibung |
|---|---|
CVE-2008-2516 | Authentication module allows authentication bypass because it uses "(x = call(args) == SUCCESS)" instead of "((x = call(args)) == SUCCESS)". |
CVE-2008-0599 | Chain: Language interpreter calculates wrong buffer size (CWE-131) by using "size = ptr ? X : Y" instead of "size = (ptr ? X : Y)" expression. |
CVE-2001-1155 | Chain: product does not properly check the result of a reverse DNS lookup because of operator precedence (CWE-783), allowing bypass of DNS-based access restrictions. |
Mögliche Gegenmaßnahmen
Phases : ImplementationRegularly wrap sub-expressions in parentheses, especially in security-critical code.
Erkennungsmethoden
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.)Wirksamkeit : High
Hinweise zur Schwachstellen-Zuordnung
Begründung : 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.Kommentar : 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.
Referenzen
REF-704
EXP00-C. Use parentheses for precedence of operationCERT.
https://www.securecoding.cert.org/confluence/display/seccode/EXP00-C.+Use+parentheses+for+precedence+of+operation
REF-62
The Art of Software Security AssessmentMark Dowd, John McDonald, Justin Schuh.
Einreichung
| Name | Organisation | Datum | Veröffentlichungsdatum | Version |
|---|---|---|---|---|
| CWE Content Team | MITRE | 1.5 |
Änderungen
| Name | Organisation | Datum | Kommentar |
|---|---|---|---|
| CWE Content Team | MITRE | updated Observed_Examples | |
| CWE Content Team | MITRE | updated Common_Consequences | |
| CWE Content Team | MITRE | updated Demonstrative_Examples, References, Relationships | |
| CWE Content Team | MITRE | updated Taxonomy_Mappings, Time_of_Introduction | |
| CWE Content Team | MITRE | updated Taxonomy_Mappings | |
| CWE Content Team | MITRE | updated Type | |
| CWE Content Team | MITRE | updated Relationships | |
| CWE Content Team | MITRE | updated Relationships | |
| CWE Content Team | MITRE | updated Relationships | |
| CWE Content Team | MITRE | updated Description | |
| CWE Content Team | MITRE | updated Relationships | |
| CWE Content Team | MITRE | updated Mapping_Notes | |
| CWE Content Team | MITRE | updated Detection_Factors, Weakness_Ordinalities |
