CWE WEAKNESSES / CWE-682
CWE-682
Incorrect Calculation
Pillar EXPLOIT LIKELIHOOD: HIGH
What it is
The product performs a calculation that generates incorrect or unintended results that are later used in security-critical decisions or resource management.
When product performs a security-critical calculation incorrectly, it might lead to incorrect resource allocations, incorrect privilege assignments, or failed comparisons among other things. Many of the direct results of an incorrect calculation can lead to even larger problems such as failed protection mechanisms or even arbitrary code execution.
Impact
| Availability | DoS: Crash, Exit, or Restart |
| Integrity, Confidentiality, Availability | DoS: Crash, Exit, or Restart, DoS: Resource Consumption (Other), Execute Unauthorized Code or Commands |
| Access Control | Gain Privileges or Assume Identity |
| Access Control | Bypass Protection Mechanism |
Mitigations
- [Implementation] Understand your programming language's underlying representation and how it interacts with numeric calculation. Pay close attention to byte size discrepancies, precision, signed/unsigned distinctions, truncation, conversion and casting between types, "not-a-number" calculations, and how your language handles numbers that are too large or too small for its underlying representation.
- [Implementation] Perform input validation on any numeric input by ensuring that it is within the expected range. Enforce that the input meets both the minimum and maximum requirements for the expected range.
- [Implementation] Use the appropriate type for the desired action. For example, in C/C++, only use unsigned types for values that could never be negative, such as height, width, or other numbers related to quantity.
- [Architecture and Design]Use languages, libraries, or frameworks that make it easier to handle numbers without unexpected consequences.Examples include safe integer handling packages such as SafeInt (C++) or IntegerLib (C or C++).
- [Architecture and Design]Use languages, libraries, or frameworks that make it easier to handle numbers without unexpected consequences.Examples include safe integer handling packages such as SafeInt (C++) or IntegerLib (C or C++).
- [Implementation] Examine compiler warnings closely and eliminate problems with potential security implications, such as signed / unsigned mismatch in memory operations, or use of uninitialized variables. Even if the weakness is rarely exploitable, a single failure may lead to the compromise of the entire system.
Real-world CVE examples
- CVE-2020-0022 — chain: mobile phone Bluetooth implementation does not include offset when calculating packet length (CWE-682), leading to out-of-bounds write (CWE-787)
- CVE-2010-1378 — Chain: incorrect calculation (CWE-682) allows attackers to bypass certificate checks (CWE-295)
- CVE-2004-1363 — substitution overflow: buffer overflow using environment variables that are expanded after the length check is performed
Related weaknesses
Test & detect
Browse all common weaknesses, check related exploited CVEs, or map to ATT&CK techniques.
Source: MITRE CWE. View on cwe.mitre.org →