Heap-based Buffer Overflow

Opis

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().

Inne nazwy

Heap Overflow

Heap Buffer Overflow

Skutki

• Availability

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

  Buffer overflows generally lead to crashes. Other attacks leading to lack of availability are possible, including putting the program into an infinite loop.

• Integrity, Confidentiality, Availability, Access Control

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

  Buffer overflows often can be used to execute arbitrary code, which is usually outside the scope of a program's implicit security policy. Besides important user data, heap-based overflows can be used to overwrite function pointers that may be living in memory, pointing it to the attacker's code. Even in applications that do not explicitly use function pointers, the run-time will usually leave many in memory. For example, object methods in C++ are generally implemented using function pointers. Even in C programs, there is often a global offset table used by the underlying runtime.

• Integrity, Confidentiality, Availability, Access Control, Other

  Execute Unauthorized Code or Commands; Bypass Protection Mechanism; Other

  When the consequence is arbitrary code execution, this can often be used to subvert any other security service.

Zapobieganie

• Pre-design: Use a language or compiler that performs automatic bounds checking.

• Architecture and Design

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

• Operation, Build and Compilation · Environment Hardening

  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.

  Skuteczność: Defense in Depth

• Operation, Build and Compilation · Environment Hardening

  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].

  Skuteczność: Defense in Depth

• Implementation

  Implement and perform bounds checking on input.

• Implementation · Libraries or Frameworks

  Do not use dangerous functions such as gets. Look for their safe equivalent, which checks for the boundary.

• Operation

  Use OS-level preventative functionality. This is not a complete solution, but it provides some defense in depth.

Przykłady podatności

• CVE-2025-46687 Chain: Javascript engine code does not perform a length check (CWE-1284) leading to integer overflow (CWE-190) causing allocation of smaller buffer than expected (CWE-131) resulting in a heap-based buffer overflow (CWE-122)
• CVE-2021-43537 Chain: in a web browser, an unsigned 64-bit integer is forcibly cast to a 32-bit integer (CWE-681) and potentially leading to an integer overflow (CWE-190). If an integer overflow occurs, this can cause heap memory corruption (CWE-122)
• CVE-2007-4268 Chain: integer signedness error (CWE-195) passes signed comparison, leading to heap overflow (CWE-122)
• CVE-2009-2523 Chain: product does not handle when an input string is not NULL terminated (CWE-170), leading to buffer over-read (CWE-125) or heap-based buffer overflow (CWE-122).
• CVE-2021-29529 Chain: machine-learning product can have a heap-based buffer overflow (CWE-122) when some integer-oriented bounds are calculated by using ceiling() and floor() on floating point values (CWE-1339)
• CVE-2010-1866 Chain: integer overflow (CWE-190) causes a negative signed value, which later bypasses a maximum-only check (CWE-839), leading to heap-based buffer overflow (CWE-122).

Słabość nadrzędna

• CWE-788 Access of Memory Location After End of Buffer
• CWE-787 Out-of-bounds Write

Kiedy powstaje

• Implementation

Dotyczy

Memory-Unsafe, C, C++, Not Technology-Specific

Uwagi

There is significant inconsistency regarding the "buffer overflow" term, which can have multiple interpretations and uses. Many people mean "writing past the end of a buffer." Others mean "writing past the end of a buffer, or before the beginning of a buffer." Still others might include "read" in the term.

Źródła

1. Writing Secure Code — Michael Howard, David LeBlanc, Chapter 5, "Heap Overruns" Page 138, Microsoft Press, 2002
2. 24 Deadly Sins of Software Security — Michael Howard, David LeBlanc, John Viega, "Sin 5: Buffer Overruns." Page 89, McGraw-Hill, 2010
3. The Art of Software Security Assessment — Mark Dowd, John McDonald, Justin Schuh, Chapter 3, "Nonexecutable Stack", Page 76, Addison Wesley, 2006
4. The Art of Software Security Assessment — Mark Dowd, John McDonald, Justin Schuh, Chapter 5, "Protection Mechanisms", Page 189, Addison Wesley, 2006
5. Address Space Layout Randomization in Windows Vista — Michael Howard
6. PaX
7. Position Independent Executables (PIE) — Grant Murphy, Red Hat, 2012
8. The CLASP Application Security Process — Secure Software, Inc., 2005
9. Bypassing Browser Memory Protections: Setting back browser security by 10 years — Alexander Sotirov and Mark Dowd, Memory information leaks, 2008
10. Prelink and address space randomization — John Richard Moser, 2006
11. Jump Over ASLR: Attacking Branch Predictors to Bypass ASLR — Dmitry Evtyushkin, Dmitry Ponomarev, Nael Abu-Ghazaleh, 2016
12. Stack Frame Canary Validation (D3-SFCV) — D3FEND, 2023
13. Segment Address Offset Randomization (D3-SAOR) — D3FEND, 2023
14. Secure by Design Alert: Eliminating Buffer Overflow Vulnerabilities — Cybersecurity and Infrastructure Security Agency, 2025
15. AddressSanitizer