rspec/rules/S2755/php/rule.adoc

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== Noncompliant Code Example

https://www.php.net/manual/fr/function.simplexml-load-string.php[SimpleXML] object:

[source,php]
----
$xml = file_get_contents("xxe.xml");
$doc = simplexml_load_string($xml, "SimpleXMLElement", LIBXML_NOENT); // Noncompliant (LIBXML_NOENT enable external entities substitution)
----

https://www.php.net/manual/fr/class.domdocument.php[DOMDocument] object:

[source,php]
----
$doc = new DOMDocument();
$doc->load("xxe.xml", LIBXML_NOENT); // Noncompliant (LIBXML_NOENT enable external entities substitution)
----

https://www.php.net/manual/fr/xmlreader.xml.php[XMLReader] object:

[source,php]
----
$reader = new XMLReader();
$reader->open("xxe.xml");
$reader->setParserProperty(XMLReader::SUBST_ENTITIES, true); // Noncompliant (SUBST_ENTITIES enable external entities substitution)
----

== Compliant Solution

https://www.php.net/manual/fr/function.simplexml-load-string.php[SimpleXML] object:

[source,php]
----
$xml = file_get_contents("xxe.xml");
$doc = simplexml_load_string($xml, "SimpleXMLElement"); // Compliant (external entities substitution are disabled by default)
----

https://www.php.net/manual/fr/class.domdocument.php[DOMDocument] object:

[source,php]
----
$doc = new DOMDocument();
$doc->load("xxe.xml"); // Compliant (external entities substitution are disabled by default)
----

https://www.php.net/manual/fr/xmlreader.xml.php[XMLReader] object:

[source,php]
----
$reader = new XMLReader();
$reader->open("xxe.xml");
$reader->setParserProperty(XMLReader::SUBST_ENTITIES, false); // Compliant (SUBST_ENTITIES set to false)
----

== See

* https://owasp.org/Top10/A05_2021-Security_Misconfiguration/[OWASP Top 10 2021 Category A5] - Security Misconfiguration
* https://www.owasp.org/index.php/Top_10-2017_A4-XML_External_Entities_(XXE)[OWASP Top 10 2017 Category A4] - XML External Entities (XXE)
* https://cheatsheetseries.owasp.org/cheatsheets/XML_External_Entity_Prevention_Cheat_Sheet.html#php[OWASP XXE Prevention Cheat Sheet]
* https://cwe.mitre.org/data/definitions/611.html[MITRE, CWE-611] - Information Exposure Through XML External Entity Reference
* https://cwe.mitre.org/data/definitions/827.html[MITRE, CWE-827] - Improper Control of Document Type Definition

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== Implementation Specification
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include::../highlighting.adoc[]

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== Comments And Links
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