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Weakness · High

CWE-611: Improper Restriction of XML External Entity Reference

What it is

The product processes an XML document that can contain XML entities with URIs that resolve to documents outside of the intended sphere of control, causing the product to embed incorrect documents into its output.

8 exploited in the wildMITRE CWE 4.19.1

Severity (our rating)
High
Likelihood of exploit
Not rated by MITRE
Introduced during
Implementation
Exploited in the wild
8 known exploited CVEs

What an attacker can do

  • Read Application Data (Confidentiality)
  • Read Files or Directories (Confidentiality)
  • Bypass Protection Mechanism (Integrity)
  • DoS: Resource Consumption (CPU) (Availability)
  • DoS: Resource Consumption (Memory) (Availability)

How to prevent it

Implementation

  • Many XML parsers and validators can be configured to disable external entity expansion.

How to find it

  • Automated Static Analysis. Automated static analysis, commonly referred to as Static Application Security Testing (SAST), can find some instances of this weakness by analyzing source code (or binary/compiled code) without having to execute it. Typically, this is done by building a model of data flow and control flow, then searching for potentially-vulnerable patterns that connect "sources" (origins of input) with "sinks" (destinations where the data interacts with external components, a lower layer such as the OS, etc.)

CWE-611 on MITRE's CWE site

Exploited in the wild: 8 CVEs

Vulnerabilities caused by CWE-611 that attackers have used, from CISA's Known Exploited Vulnerabilities catalog, newest first.

All known exploited vulnerabilities

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Source: MITRE Common Weakness Enumeration, CWE version 4.19.1. CWE is a trademark of The MITRE Corporation.