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Weakness (CWE)

CWE-170: Improper Null Termination

Base Incomplete

The product does not terminate or incorrectly terminates a string or array with a null character or equivalent terminator.

How to prevent it (5 mitigations)

  1. Requirements

    Use a language that is not susceptible to these issues. However, be careful of null byte interaction errors (CWE-626) with lower-level constructs that may be written in a language that is susceptible.

  2. Implementation

    Ensure that all string functions used are understood fully as to how they append null characters. Also, be wary of off-by-one errors when appending nulls to the end of strings.

  3. Implementation

    If performance constraints permit, special code can be added that validates null-termination of string buffers, this is a rather naive and error-prone solution.

  4. Implementation

    Switch to bounded string manipulation functions. Inspect buffer lengths involved in the buffer overrun trace reported with the defect.

  5. Implementation

    Add code that fills buffers with nulls (however, the length of buffers still needs to be inspected, to ensure that the non null-terminated string is not written at the physical end of the buffer).

Source: MITRE CWE-170

All Critical High Medium Low Exploited only Public exploit

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