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CWE-96

Improper Neutralization of Directives in Statically Saved Code ('Static Code Injection')

Base
Draft

Description

The product receives input from an upstream component, but it does not neutralize or incorrectly neutralizes code syntax before inserting the input into an executable resource, such as a library, configuration file, or template.

Common Consequences

Scope

Confidentiality

Impact

Read Files or Directories, Read Application Data

Scope

Access Control

Impact

Bypass Protection Mechanism

Scope

Access Control

Impact

Gain Privileges or Assume Identity

Scope

Integrity
Confidentiality
Availability
Other

Impact

Execute Unauthorized Code or Commands

Scope

Non-Repudiation

Impact

Hide Activities

Potential Mitigations

Implementation

Assume all input is malicious. Use an "accept known good" input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does. When performing input validation, consider all potentially relevant properties, including length, type of input, the full range of acceptable values, missing or extra inputs, syntax, consistency across related fields, and conformance to business rules. As an example of business rule logic, "boat" may be syntactically valid because it only contains alphanumeric characters, but it is not valid if the input is only expected to contain colors such as "red" or "blue." Do not rely exclusively on looking for malicious or malformed inputs. This is likely to miss at least one undesirable input, especially if the code's environment changes. This can give attackers enough room to bypass the intended validation. However, denylists can be useful for detecting potential attacks or determining which inputs are so malformed that they should be rejected outright.

Implementation

Perform proper output validation and escaping to neutralize all code syntax from data written to code files.

CVE-2002-0495

Perl code directly injected into CGI library file from parameters to another CGI program.

CVE-2005-1876

Direct PHP code injection into supporting template file.

CVE-2005-1894

Direct code injection into PHP script that can be accessed by attacker.

CVE-2003-0395

PHP code from User-Agent HTTP header directly inserted into log file implemented as PHP script.

CVE-2007-6652

chain: execution after redirect allows non-administrator to perform static code injection.

Applicable Platforms

PHP
Perl
Interpreted

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