CWE-196 - Unsigned to Signed Conversion Error
CWE-196 Medium
- Abstraction:
- Variant
- Structure:
- Simple
- Status:
- Draft
- Weakness Name
Unsigned to Signed Conversion Error
- Description
The product uses an unsigned primitive and performs a cast to a signed primitive, which can produce an unexpected value if the value of the unsigned primitive can not be represented using a signed primitive.
Although less frequent an issue than signed-to-unsigned conversion, unsigned-to-signed conversion can be the perfect precursor to dangerous buffer underwrite conditions that allow attackers to move down the stack where they otherwise might not have access in a normal buffer overflow condition. Buffer underwrites occur frequently when large unsigned values are cast to signed values, and then used as indexes into a buffer or for pointer arithmetic.
- Common Consequences
Scope: Availability
Impact: DoS: Crash, Exit, or Restart
Notes: Incorrect sign conversions generally lead to undefined behavior, and therefore crashes.
Scope: Integrity
Impact: Modify Memory
Notes: If a poor cast lead to a buffer overflow or similar condition, data integrity may be affected.
Scope: Integrity, Confidentiality, Availability, Access Control
Impact: Execute Unauthorized Code or Commands, Bypass Protection Mechanism
Notes: Improper signed-to-unsigned conversions without proper checking can sometimes trigger buffer overflows which can be used to execute arbitrary code. This is usually outside the scope of a program's implicit security policy.
- Related Weaknesses
- Release Date:
- 2006-07-19
- Latest Modification Date:
- 2023-06-29
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