DetailedSeverity: HighCAPEC-10

CAPEC-10: Buffer Overflow via Environment Variables

Description

This attack pattern involves causing a buffer overflow through manipulation of environment variables. Once the adversary finds that they can modify an environment variable, they may try to overflow associated buffers. This attack leverages implicit trust often placed in environment variables.

Likelihood of attack: High
Typical severity: High
Abstraction: DetailedA low-level, detailed pattern, often for a particular technology.

Mechanism of attack: Manipulate Data Structures

Prerequisites

The application uses environment variables.
An environment variable exposed to the user is vulnerable to a buffer overflow.
The vulnerable environment variable uses untrusted data.
Tainted data used in the environment variables is not properly validated. For instance boundary checking is not done before copying the input data to a buffer.

Skills required

LowAn attacker can simply overflow a buffer by inserting a long string into an attacker-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
ConfidentialityAccess ControlAuthorization
Gain Privileges

Mitigations

Do not expose environment variable to the user.
Do not use untrusted data in your environment variables.
Use a language or compiler that performs automatic bounds checking
There are tools such as Sharefuzz which is an environment variable fuzzer for Unix that support loading a shared library. You can use Sharefuzz to determine if you are exposing an environment variable vulnerable to buffer overflow.

Related weaknesses (CWE)

Related attack patterns

Parent

CAPEC-100Overflow BuffersStandard

Prerequisites

The application uses environment variables.

An environment variable exposed to the user is vulnerable to a buffer overflow.

The vulnerable environment variable uses untrusted data.

Tainted data used in the environment variables is not properly validated. For instance boundary checking is not done before copying the input data to a buffer.

Mitigations

Do not expose environment variable to the user.

Do not use untrusted data in your environment variables.

Use a language or compiler that performs automatic bounds checking

There are tools such as Sharefuzz which is an environment variable fuzzer for Unix that support loading a shared library. You can use Sharefuzz to determine if you are exposing an environment variable vulnerable to buffer overflow.