Software systems can be validated as conforming to the CERT Perl Secure Coding Standard. Source code analysis tools, including compilers and static analysis tools, can be certified as able to validate source code as conforming to this standard.

Source Code Compliance

The CERT Perl Secure Coding Standard can be used as a measure of software security by determining the degree to which a software system complies with the rules and recommendations in this standard. While compliance does not guarantee the absence of vulnerabilities (for example, vulnerabilities resulting from design flaws), it does guarantee the absence of coding errors that are commonly found to be the root causes of vulnerabilities.

The easiest way to validate code as compliant with the CERT Perl Secure Coding Standard is to use a certified source code analysis tool.


Rules and recommendations in this standard are classified into three levels. (See Risk Assessment.) Emphasis should be placed on conformance Level 1 (L1) rules. Software systems that have been validated as complying with all Level 1 rules are considered to be L1 conforming. Software systems can be assessed as L1, L2, or fully conforming depending on the set of rules to which the system has been validated.

Rules versus Recommendations

To claim compliance with this standard, conformance to secure coding rules must be demonstrated unless an exceptional condition exists. If an exceptional condition is claimed, the exception must correspond to a predefined exceptional condition and the application of this exception must be documented in the source code.

Compliance with recommendations is not necessary to claim compliance with this standard. It is possible, however, to claim compliance with recommendations (especially in cases in which compliance can be verified).

Deviation Procedure

Strict adherence to all rules is unlikely. Consequently, deviations associated with individual situations are permissible.

Deviations may occur for a specific instance, typically in response to circumstances that arise during the development process or for a systematic use of a particular construct in a particular circumstance. Systematic deviations are usually agreed upon at the start of a project.

For these secure coding rules to have authority, it is necessary that a formal procedure be used to authorize these deviations rather than an individual programmer having discretion to deviate at will. The use of a deviation must be justified on the basis of both necessity and security. Rules that have a high severity and/or a high likelihood require a more stringent process for agreeing to a deviation than do rules with a low severity that are unlikely to result in a vulnerability.

To claim compliance with this standard, software developers must be able to produce on request documentation as to which systematic and specific deviations have been permitted during development.

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