CAPEC-46: Overflow Variables and Tags

Prerequisites

• The target program consumes user-controllable data in the form of tags or variables.
• The target program does not perform sufficient boundary checking.

Skills required

• LowAn adversary can simply overflow a buffer by inserting a long string into an adversary-modifiable injection vector. The result can be a DoS.
• HighExploiting a buffer overflow to inject malicious code into the stack of a software system or even the heap can require a higher skill level.

Consequences

• Availability

  Unreliable Execution

• ConfidentialityIntegrityAvailability

  Execute Unauthorized Commands

  Run Arbitrary Code

• Confidentiality

  Read Data

• Integrity

  Modify Data

Mitigations

• Use a language or compiler that performs automatic bounds checking.
• Use an abstraction library to abstract away risky APIs. Not a complete solution.
• Compiler-based canary mechanisms such as StackGuard, ProPolice and the Microsoft Visual Studio /GS flag. Unless this provides automatic bounds checking, it is not a complete solution.
• Use OS-level preventative functionality. Not a complete solution.
• Do not trust input data from user. Validate all user input.

Related weaknesses (CWE)

• CWE-20Improper Input Validation
• CWE-74Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection')
• CWE-118Incorrect Access of Indexable Resource ('Range Error')
• CWE-119Improper Restriction of Operations within the Bounds of a Memory Buffer
• CWE-120Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')
• CWE-680Integer Overflow to Buffer Overflow
• CWE-697Incorrect Comparison
• CWE-733Compiler Optimization Removal or Modification of Security-critical Code

Related attack patterns

Parent

• CAPEC-100Overflow BuffersStandard