CWE-611: Improper Restriction of XML External Entity Reference
XML documents optionally contain a Document Type Definition (DTD), which, among other features, enables the definition of XML entities. It is possible to define an entity by providing a substitution string in the form of a URI. The XML parser can access the contents of this URI and embed these contents back into the XML document for further processing.
By submitting an XML file that defines an external entity with a file:// URI, an attacker can cause the processing application to read the contents of a local file. For example, a URI such as "file:///c:/winnt/win.ini" designates (in Windows) the file C:\Winnt\win.ini, or file:///etc/passwd designates the password file in Unix-based systems. Using URIs with other schemes such as http://, the attacker can force the application to make outgoing requests to servers that the attacker cannot reach directly, which can be used to bypass firewall restrictions or hide the source of attacks such as port scanning.
Once the content of the URI is read, it is fed back into the application that is processing the XML. This application may echo back the data (e.g. in an error message), thereby exposing the file contents.
Modes of Introduction
Phase | Note |
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Implementation | REALIZATION: This weakness is caused during implementation of an architectural security tactic. |
Applicable Platforms
Type | Class | Name | Prevalence |
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Language | XML | ||
Technology | Web Based |
Relationships
View | Weakness | |||||||
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# ID | View | Status | # ID | Name | Abstraction | Structure | Status | |
CWE-1000 | Research Concepts | Draft | CWE-610 | Externally Controlled Reference to a Resource in Another Sphere | Class | Simple | Draft | |
CWE-1003 | Weaknesses for Simplified Mapping of Published Vulnerabilities | Incomplete | CWE-610 | Externally Controlled Reference to a Resource in Another Sphere | Class | Simple | Draft | |
CWE-1000 | Research Concepts | Draft | CWE-441 | Unintended Proxy or Intermediary ('Confused Deputy') | Class | Simple | Draft |
Common Attack Pattern Enumeration and Classification (CAPEC)
The Common Attack Pattern Enumeration and Classification (CAPECâ„¢) effort provides a publicly available catalog of common attack patterns that helps users understand how adversaries exploit weaknesses in applications and other cyber-enabled capabilities.
CAPEC at Mitre.orgCVEs Published
CVSS Severity
CVSS Severity - By Year
CVSS Base Score
# CVE | Description | CVSS | EPSS | EPSS Trend (30 days) | Affected Products | Weaknesses | Security Advisories | Exploits | PoC | Pubblication Date | Modification Date |
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# CVE | Description | CVSS | EPSS | EPSS Trend (30 days) | Affected Products | Weaknesses | Security Advisories | PoC | Pubblication Date | Modification Date |