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CWE-121

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CWE-121

Stack-based Buffer Overflow

Variant
Draft

Description

A stack-based buffer overflow condition is a condition where the buffer being overwritten is allocated on the stack (i.e., is a local variable or, rarely, a parameter to a function).

Common Consequences

Scope

Availability

Impact

Modify Memory, DoS: Crash, Exit, or Restart, DoS: Resource Consumption (CPU), DoS: Resource Consumption (Memory)

Scope

Integrity
Confidentiality
Availability
Access Control

Impact

Modify Memory, Execute Unauthorized Code or Commands, Bypass Protection Mechanism

Scope

Integrity
Confidentiality
Availability
Access Control
Other

Impact

Modify Memory, Execute Unauthorized Code or Commands, Bypass Protection Mechanism, Other

Potential Mitigations

Operation
Build and Compilation

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.

Architecture and Design

Use an abstraction library to abstract away risky APIs. Not a complete solution.

Implementation

Implement and perform bounds checking on input.

Implementation

Do not use dangerous functions such as gets. Use safer, equivalent functions which check for boundary errors.

Operation
Build and Compilation

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].

CVE-2021-35395

Stack-based buffer overflows in SFK for wifi chipset used for IoT/embedded devices, as exploited in the wild per CISA KEV.

Applicable Platforms

Memory-Unsafe
C
C++

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