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Weakness (CWE)

CWE-190: Integer Overflow or Wraparound

Base

The product performs a calculation that can
produce an integer overflow or wraparound when the logic
assumes that the resulting value will always be larger than
the original value. This occurs when an integer value is
incremented to a value that is too large to store in the
associated representation. When this occurs, the value may
become a very small or negative number.

How to prevent it (7 mitigations)

  1. Requirements

    Ensure that all protocols are strictly defined, such that all out-of-bounds behavior can be identified simply, and require strict conformance to the protocol.

  2. Requirements

    Use a language that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.

    If possible, choose a language or compiler that performs automatic bounds checking.

  3. Architecture and Design

    Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid [REF-1482].

    Use 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++). [REF-106]

  4. 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.

    Use unsigned integers where possible. This makes it easier to perform validation for integer overflows. When signed integers are required, ensure that the range check includes minimum values as well as maximum values.

  5. Implementation

    Understand the programming language's underlying representation and how it interacts with numeric calculation (CWE-681). Pay close attention to byte size discrepancies, precision, signed/unsigned distinctions, truncation, conversion and casting between types, "not-a-number" calculations, and how the language handles numbers that are too large or too small for its underlying representation. [REF-7]

    Also be careful to account for 32-bit, 64-bit, and other potential differences that may affect the numeric representation.

  6. Architecture and Design

    For any security checks that are performed on the client side, ensure that these checks are duplicated on the server side, in order to avoid CWE-602. Attackers can bypass the client-side checks by modifying values after the checks have been performed, or by changing the client to remove the client-side checks entirely. Then, these modified values would be submitted to the server.

  7. 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.

Source: MITRE CWE-190

All Critical High Medium Low Exploited only Public exploit

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