What is the name of pythons built in module for xml processing?

Source code: Lib/xml/


Python’s interfaces for processing XML are grouped in the xml package.

Warning

The XML modules are not secure against erroneous or maliciously constructed data. If you need to parse untrusted or unauthenticated data see the XML vulnerabilities and The defusedxml Package sections.

It is important to note that modules in the xml package require that there be at least one SAX-compliant XML parser available. The Expat parser is included with Python, so the xml.parsers.expat module will always be available.

The documentation for the xml.dom and xml.sax packages are the definition of the Python bindings for the DOM and SAX interfaces.

The XML handling submodules are:

  • xml.etree.ElementTree: the ElementTree API, a simple and lightweight XML processor

  • xml.dom: the DOM API definition

  • xml.dom.minidom: a minimal DOM implementation

  • xml.dom.pulldom: support for building partial DOM trees

  • xml.sax: SAX2 base classes and convenience functions

  • xml.parsers.expat: the Expat parser binding

XML vulnerabilities¶

The XML processing modules are not secure against maliciously constructed data. An attacker can abuse XML features to carry out denial of service attacks, access local files, generate network connections to other machines, or circumvent firewalls.

The following table gives an overview of the known attacks and whether the various modules are vulnerable to them.

kind

sax

etree

minidom

pulldom

xmlrpc

billion laughs

Vulnerable (1)

Vulnerable (1)

Vulnerable (1)

Vulnerable (1)

Vulnerable (1)

quadratic blowup

Vulnerable (1)

Vulnerable (1)

Vulnerable (1)

Vulnerable (1)

Vulnerable (1)

external entity expansion

Safe (5)

Safe (2)

Safe (3)

Safe (5)

Safe (4)

DTD retrieval

Safe (5)

Safe

Safe

Safe (5)

Safe

decompression bomb

Safe

Safe

Safe

Safe

Vulnerable

  1. Expat 2.4.1 and newer is not vulnerable to the “billion laughs” and “quadratic blowup” vulnerabilities. Items still listed as vulnerable due to potential reliance on system-provided libraries. Check pyexpat.EXPAT_VERSION.

  2. xml.etree.ElementTree doesn’t expand external entities and raises a ParserError when an entity occurs.

  3. xml.dom.minidom doesn’t expand external entities and simply returns the unexpanded entity verbatim.

  4. xmlrpclib doesn’t expand external entities and omits them.

  5. Since Python 3.7.1, external general entities are no longer processed by default.

billion laughs / exponential entity expansion

The Billion Laughs attack – also known as exponential entity expansion – uses multiple levels of nested entities. Each entity refers to another entity several times, and the final entity definition contains a small string. The exponential expansion results in several gigabytes of text and consumes lots of memory and CPU time.

quadratic blowup entity expansion

A quadratic blowup attack is similar to a Billion Laughs attack; it abuses entity expansion, too. Instead of nested entities it repeats one large entity with a couple of thousand chars over and over again. The attack isn’t as efficient as the exponential case but it avoids triggering parser countermeasures that forbid deeply nested entities.

external entity expansion

Entity declarations can contain more than just text for replacement. They can also point to external resources or local files. The XML parser accesses the resource and embeds the content into the XML document.

DTD retrieval

Some XML libraries like Python’s xml.dom.pulldom retrieve document type definitions from remote or local locations. The feature has similar implications as the external entity expansion issue.

decompression bomb

Decompression bombs (aka ZIP bomb) apply to all XML libraries that can parse compressed XML streams such as gzipped HTTP streams or LZMA-compressed files. For an attacker it can reduce the amount of transmitted data by three magnitudes or more.

The documentation for defusedxml on PyPI has further information about all known attack vectors with examples and references.

The defusedxml Package¶

defusedxml is a pure Python package with modified subclasses of all stdlib XML parsers that prevent any potentially malicious operation. Use of this package is recommended for any server code that parses untrusted XML data. The package also ships with example exploits and extended documentation on more XML exploits such as XPath injection.

What are XML libraries for Python?

The Python standard library provides a minimal but useful set of interfaces to work with XML. The two most basic and broadly used APIs to XML data are the SAX and DOM interfaces. Simple API for XML (SAX) − Here, you register callbacks for events of interest and then let the parser proceed through the document.

What is the name of the Python object that represents XML data?

The DOM is a standard tree representation for XML data. The Document Object Model is being defined by the W3C in stages, or “levels” in their terminology. The Python mapping of the API is substantially based on the DOM Level 2 recommendation. DOM applications typically start by parsing some XML into a DOM.

How does Python process XML data?

In order to parse XML document you need to have the entire document in memory..
To parse XML document..
Import xml.dom.minidom..
Use the function “parse” to parse the document ( doc=xml.dom.minidom.parse (file name);.
Call the list of XML tags from the XML document using code (=doc.getElementsByTagName( “name of xml tags”).

What is XML write a program of XML parsing in Python?

This article focuses on how one can parse a given XML file and extract some useful data out of it in a structured way. XML: XML stands for eXtensible Markup Language. It was designed to store and transport data. It was designed to be both human- and machine-readable.

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