CWE-122

Heap-based Buffer Overflow
AI Translation Available

A heap overflow condition is a buffer overflow, where the buffer that can be overwritten is allocated in the heap portion of memory, generally meaning that the buffer was allocated using a routine such as malloc().

Status
draft
Abstraction
variant
Likelihood
high
C C++ Memory-Unsafe

Common Consequences

availability integrity confidentiality access control other
Impacts
dos: crash, exit, or restart dos: resource consumption (cpu) dos: resource consumption (memory) execute unauthorized code or commands bypass protection mechanism modify memory other

Detection Methods

fuzzing automated dynamic analysis

Potential Mitigations

Phases:
architecture and design operation build and compilation implementation
Descriptions:
• Use an abstraction library to abstract away risky APIs. Not a complete solution.
• Pre-design: Use a language or compiler that performs automatic bounds checking.
• Use automatic buffer overflow detection mechanisms that are offered by certain compilers or compiler extensions. Examples include: the Microsoft Visual Studio /GS flag, Fedora/Red Hat FORTIFY_SOURCE GCC flag, StackGuard, and ProPolice, which provide various mechanisms including canary-based detection and range/index checking. D3-SFCV (Stack Frame Canary Validation) from D3FEND [REF-1334] discusses canary-based detection in detail.
• Implement and perform bounds checking on input.
• Use OS-level preventative functionality. This is not a complete solution, but it provides some defense in depth.
• Run or compile the software using features or extensions that randomly arrange the positions of a program's executable and libraries in memory. Because this makes the addresses unpredictable, it can prevent an attacker from reliably jumping to exploitable code. Examples include Address Space Layout Randomization (ASLR) [REF-58] [REF-60] and Position-Independent Executables (PIE) [REF-64]. Imported modules may be similarly realigned if their default memory addresses conflict with other modules, in a process known as "rebasing" (for Windows) and "prelinking" (for Linux) [REF-1332] using randomly generated addresses. ASLR for libraries cannot be used in conjunction with prelink since it would require relocating the libraries at run-time, defeating the whole purpose of prelinking. For more information on these techniques see D3-SAOR (Segment Address Offset Randomization) from D3FEND [REF-1335].
• Do not use dangerous functions such as gets. Look for their safe equivalent, which checks for the boundary.

Functional Areas

memory management