How does a Overflow Buffers attack work?

It typically unfolds over 4 phases. It begins with: [Identify target application] The adversary identifies a target application or program to perform the buffer overflow on. Adversaries often look for applications that accept user input and that perform manual memory management.

How do you prevent CAPEC-100?

Use a language or compiler that performs automatic bounds checking.

What weaknesses does CAPEC-100 target?

CAPEC-100 exploits 6 CWE weaknesses, including CWE-119 (Improper Restriction of Operations within the Bounds of a Memory Buffer), CWE-120 (Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')), CWE-129 (Improper Validation of Array Index), CWE-131 (Incorrect Calculation of Buffer Size).

How severe is CAPEC-100?

MITRE rates CAPEC-100 as Very High severity with high likelihood of attack.

Standard attack pattern

Draft

CAPEC-100: Overflow Buffers

Buffer Overflow attacks target improper or missing bounds checking on buffer operations, typically triggered by input injected by an adversary. As a consequence, an adversary is able to write past the boundaries of allocated buffer regions in memory, causing a program crash or potentially redirection of execution as per the adversaries' choice.

Last updated June 1, 2026

Very High

Typical severity

Per MITRE

High

Likelihood of attack

Per MITRE

Related weaknesses

CWEs this targets

Standard

Abstraction

MITRE classification

Overview

CAPEC-100 (Overflow Buffers) is a standard-level attack pattern catalogued by MITRE in the Common Attack Pattern Enumeration and Classification (CAPEC). It describes a recurring method attackers use to exploit software weaknesses.

How the attack works

The phases an attacker typically follows to carry out this attack.

Step 1
Explore
[Identify target application] The adversary identifies a target application or program to perform the buffer overflow on. Adversaries often look for applications that accept user input and that perform manual memory management.
Step 2
Experiment
[Find injection vector] The adversary identifies an injection vector to deliver the excessive content to the targeted application's buffer.
- Provide large input to a program or application and observe the behavior. If there is a crash, this means that a buffer overflow attack is possible.
Step 3
Experiment
[Craft overflow content] The adversary crafts the content to be injected. If the intent is to simply cause the software to crash, the content need only consist of an excessive quantity of random data. If the intent is to leverage the overflow for execution of arbitrary code, the adversary crafts the payload in such a way that the overwritten return address is replaced with one of the adversary's choosing.
- Create malicious shellcode that will execute when the program execution is returned to it.
- Use a NOP-sled in the overflow content to more easily "slide" into the malicious code. This is done so that the exact return address need not be correct, only in the range of all of the NOPs
Step 4
Exploit
[Overflow the buffer] Using the injection vector, the adversary injects the crafted overflow content into the buffer.

What the attacker needs

Prerequisites

Targeted software performs buffer operations.
Targeted software inadequately performs bounds-checking on buffer operations.
Adversary has the capability to influence the input to buffer operations.

Skills required

Low skill: In most cases, overflowing a buffer does not require advanced skills beyond the ability to notice an overflow and stuff an input variable with content.
High skill: In cases of directed overflows, where the motive is to divert the flow of the program or application as per the adversaries' bidding, high level skills are required. This may involve detailed knowledge of the target system architecture and kernel.

Resources required

None: No specialized resources are required to execute this type of attack. Detecting and exploiting a buffer overflow does not require any resources beyond knowledge of and access to the target system.

Consequences

What a successful CAPEC-100 attack can achieve.

Unreliable Execution

Affects: Availability

Execute Unauthorized Commands

Affects: Confidentiality, Integrity, Availability

Run Arbitrary Code

Gain Privileges

Affects: Confidentiality, Access Control, Authorization

How to mitigate it

Defenses that reduce the risk of CAPEC-100.

Use a language or compiler that performs automatic bounds checking.
Use secure functions not vulnerable to buffer overflow.
If you have to use dangerous functions, make sure that you do boundary checking.
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.
Utilize static source code analysis tools to identify potential buffer overflow weaknesses in the software.

How to detect it

Indicators that this attack may be underway.

An attack designed to leverage a buffer overflow and redirect execution as per the adversary's bidding is fairly difficult to detect. An attack aimed solely at bringing the system down is usually preceded by a barrage of long inputs that make no sense. In either case, it is likely that the adversary would have resorted to a few hit-or-miss attempts that will be recorded in the system event logs, if they exist.

Examples

The most straightforward example is an application that reads in input from the user and stores it in an internal buffer but does not check that the size of the input data is less than or equal to the size of the buffer. If the user enters excessive length data, the buffer may overflow leading to the application crashing, or worse, enabling the user to cause execution of injected code.

Many web servers enforce security in web applications through the use of filter plugins. An example is the SiteMinder plugin used for authentication. An overflow in such a plugin, possibly through a long URL or redirect parameter, can allow an adversary not only to bypass the security checks but also execute arbitrary code on the target web server in the context of the user that runs the web server process.

Terminology & mappings

Mapped taxonomies

WASC: Buffer Overflow (07)
OWASP Attacks: Buffer overflow attack

Frequently asked questions

Common questions about CAPEC-100.

What is CAPEC-100?: Buffer Overflow attacks target improper or missing bounds checking on buffer operations, typically triggered by input injected by an adversary. As a consequence, an adversary is able to write past the boundaries of allocated buffer regions in memory, causing a program crash or potentially redirection of execution as per the adversaries' choice.
How does a Overflow Buffers attack work?: It typically unfolds over 4 phases. It begins with: [Identify target application] The adversary identifies a target application or program to perform the buffer overflow on. Adversaries often look for applications that accept user input and that perform manual memory management.
How do you prevent CAPEC-100?: Use a language or compiler that performs automatic bounds checking.
What weaknesses does CAPEC-100 target?: CAPEC-100 exploits 6 CWE weaknesses, including CWE-119 (Improper Restriction of Operations within the Bounds of a Memory Buffer), CWE-120 (Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')), CWE-129 (Improper Validation of Array Index), CWE-131 (Incorrect Calculation of Buffer Size).
How severe is CAPEC-100?: MITRE rates CAPEC-100 as Very High severity with high likelihood of attack.

References

Attack-pattern data is sourced from the MITRE CAPEC catalog (v3.9). Weakness associations link to the corresponding CWE entries on RadicalNotion.AI.

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