This attack pattern involves causing a buffer overflow through manipulation of environment variables. Once the attacker 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.
The attacker tries to find an environment variable which can be overwritten for instance by gathering information about the target host (error pages, software's version number, etc.).
The attacker manipulates the environment variable to contain excessive-length content to cause a buffer overflow.
The attacker potentially leverages the buffer overflow to inject maliciously crafted code in an attempt to execute privileged command on the target environment.
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.
An attacker can simply overflow a buffer by inserting a long string into an attacker-modifiable injection vector. The result can be a DoS.
Exploiting a buffer overflow to inject malicious code into the stack of a software system or even the heap can require a higher skill level.
|A v a i l a b i l i t y||Unreliable Execution|
|Confidentiality Integrity Availability||Execute Unauthorized Commands|
|C o n f i d e n t i a l i t y||Read Data|
|I n t e g r i t y||Modify Data|
|Confidentiality Access Control Authorization||Gain Privileges|
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 [R.10.3] 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.
A buffer overflow in sccw allows local users to gain root access via the $HOME environmental variable.See also: CVE-1999-0906
A buffer overflow in the rlogin program involves its consumption of the TERM environmental variable.See also: CVE-1999-0046
2014-06-23 | CAPEC Content Team | The MITRE Corporation
2017-01-09 | CAPEC Content Team | The MITRE Corporation
2018-07-31 | CAPEC Content Team | The MITRE Corporation