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Weakness · High

CWE-193: Off-by-one Error

What it is

A product calculates or uses an incorrect maximum or minimum value that is 1 more, or 1 less, than the correct value.

1 exploited in the wildMITRE CWE 4.19.1

Severity (our rating)
High
Likelihood of exploit
Not rated by MITRE
Introduced during
Implementation
Exploited in the wild
1 known exploited CVE

What an attacker can do

  • DoS: Crash, Exit, or Restart (Availability)
  • DoS: Resource Consumption (CPU) (Availability)
  • DoS: Resource Consumption (Memory) (Availability)
  • DoS: Instability (Availability)
  • Modify Memory (Integrity)
  • Execute Unauthorized Code or Commands (Confidentiality, Availability, Access Control)
  • Bypass Protection Mechanism (Confidentiality, Availability, Access Control)

How to prevent it

Implementation

  • When copying character arrays or using character manipulation methods, the correct size parameter must be used to account for the null terminator that needs to be added at the end of the array. Some examples of functions susceptible to this weakness in C include strcpy(), strncpy(), strcat(), strncat(), printf(), sprintf(), scanf() and sscanf().

How to find it

  • 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.)

CWE-193 on MITRE's CWE site

Exploited in the wild: 1 CVE

Vulnerabilities caused by CWE-193 that attackers have used, from CISA's Known Exploited Vulnerabilities catalog, newest first.

All known exploited vulnerabilities

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Source: MITRE Common Weakness Enumeration, CWE version 4.19.1. CWE is a trademark of The MITRE Corporation.