계: Environment

이 섹션에는 소스 코드 외부에 있지만 제작 중인 제품의 보안에는 여전히 중요한 내용이 모두 포함되어 있습니다. 이 섹션에서 다루는 문제들은 소스 코드와 직접적으로 관련이 없기 때문에 나머지 섹션과 분리했습니다.

Weak XML Schema: Unbounded Occurrences

Universal

Abstract

maxOccurs 값을 제한 없는 수로 설정하면 리소스가 고갈되고 궁극적으로 Denial of Service 공격이 발생할 수 있습니다.

Explanation

XML 문서 처리에는 계산 비용이 많이 들 수 있습니다. 공격자는 응용 프로그램의 시스템 리소스를 고갈시키는 매우 많은 수의 요소를 응용 프로그램에 제공하여 제한 없는 수의 요소를 허용하는 스키마를 이용할 수 있습니다.

다음은 제한 없는 수의 bar 요소를 허용하는 스키마의 예입니다.


<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema" >
  <xs:element name="foo" >
    <xs:complexType>
      <xs:sequence>
	<xs:element name="bar" maxOccurs="unbounded" />
      </xs:sequence>
    </xs:complexType>
  </xs:element>
</xs:schema>

References

[1] XML Schema Part 1: Structures Second Edition W3C

[2] Roger L. Costello Constrain the Number of Occurrences of Elements in your XML Schema

[3] Standards Mapping - Common Weakness Enumeration CWE ID 400, CWE ID 770

[4] Standards Mapping - Common Weakness Enumeration Top 25 2019 [20] CWE ID 400

[5] Standards Mapping - Common Weakness Enumeration Top 25 2020 [23] CWE ID 400

[6] Standards Mapping - Common Weakness Enumeration Top 25 2022 [23] CWE ID 400

[7] Standards Mapping - Common Weakness Enumeration Top 25 2024 [24] CWE ID 400

[8] Standards Mapping - DISA Control Correlation Identifier Version 2 CCI-001094, CCI-001310, CCI-002385

[9] Standards Mapping - General Data Protection Regulation (GDPR) Indirect Access to Sensitive Data

[10] Standards Mapping - NIST Special Publication 800-53 Revision 4 SC-5 Denial of Service Protection (P1), SI-10 Information Input Validation (P1)

[11] Standards Mapping - NIST Special Publication 800-53 Revision 5 SC-5 Denial of Service Protection, SI-10 Information Input Validation

[12] Standards Mapping - OWASP API 2023 API8 Security Misconfiguration

[13] Standards Mapping - OWASP Application Security Verification Standard 4.0 8.1.4 General Data Protection (L2 L3), 11.1.3 Business Logic Security Requirements (L1 L2 L3), 11.1.4 Business Logic Security Requirements (L1 L2 L3), 12.1.1 File Upload Requirements (L1 L2 L3), 12.1.3 File Upload Requirements (L2 L3), 13.2.4 RESTful Web Service Verification Requirements (L2 L3)

[14] Standards Mapping - OWASP Mobile 2014 M1 Weak Server Side Controls

[15] Standards Mapping - OWASP Mobile 2024 M8 Security Misconfiguration

[16] Standards Mapping - OWASP Top 10 2004 A9 Application Denial of Service

[17] Standards Mapping - OWASP Top 10 2010 A6 Security Misconfiguration

[18] Standards Mapping - OWASP Top 10 2013 A5 Security Misconfiguration

[19] Standards Mapping - OWASP Top 10 2017 A6 Security Misconfiguration

[20] Standards Mapping - OWASP Top 10 2021 A05 Security Misconfiguration

[21] Standards Mapping - Payment Card Industry Data Security Standard Version 1.1 Requirement 6.5.9

[22] Standards Mapping - Payment Card Industry Data Security Standard Version 3.0 Requirement 6.5.6

[23] Standards Mapping - Payment Card Industry Data Security Standard Version 3.1 Requirement 6.5.6

[24] Standards Mapping - Payment Card Industry Data Security Standard Version 3.2 Requirement 6.5.6

[25] Standards Mapping - Payment Card Industry Data Security Standard Version 3.2.1 Requirement 6.5.6

[26] Standards Mapping - Payment Card Industry Data Security Standard Version 4.0 Requirement 6.2.4

[27] Standards Mapping - Payment Card Industry Data Security Standard Version 4.0.1 Requirement 6.2.4

[28] Standards Mapping - Payment Card Industry Software Security Framework 1.0 Control Objective 4.2 - Critical Asset Protection

[29] Standards Mapping - Payment Card Industry Software Security Framework 1.1 Control Objective 4.2 - Critical Asset Protection

[30] Standards Mapping - Payment Card Industry Software Security Framework 1.2 Control Objective 4.2 - Critical Asset Protection

[31] Standards Mapping - SANS Top 25 2010 Risky Resource Management - CWE ID 770

[32] Standards Mapping - Security Technical Implementation Guide Version 3.1 APP6080 CAT II

[33] Standards Mapping - Security Technical Implementation Guide Version 3.4 APP6080 CAT II

[34] Standards Mapping - Security Technical Implementation Guide Version 3.5 APP6080 CAT II

[35] Standards Mapping - Security Technical Implementation Guide Version 3.6 APP6080 CAT II

[36] Standards Mapping - Security Technical Implementation Guide Version 3.7 APP6080 CAT II

[37] Standards Mapping - Security Technical Implementation Guide Version 3.9 APP6080 CAT II

[38] Standards Mapping - Security Technical Implementation Guide Version 3.10 APP6080 CAT II

[39] Standards Mapping - Security Technical Implementation Guide Version 4.2 APSC-DV-002390 CAT II, APSC-DV-002400 CAT II, APSC-DV-002550 CAT I

[40] Standards Mapping - Security Technical Implementation Guide Version 4.3 APSC-DV-002390 CAT II, APSC-DV-002400 CAT II, APSC-DV-002550 CAT I

[41] Standards Mapping - Security Technical Implementation Guide Version 4.4 APSC-DV-002390 CAT II, APSC-DV-002400 CAT II, APSC-DV-002550 CAT I

[42] Standards Mapping - Security Technical Implementation Guide Version 4.5 APSC-DV-002390 CAT II, APSC-DV-002400 CAT II, APSC-DV-002550 CAT I

[43] Standards Mapping - Security Technical Implementation Guide Version 4.6 APSC-DV-002390 CAT II, APSC-DV-002400 CAT II, APSC-DV-002550 CAT I

[44] Standards Mapping - Security Technical Implementation Guide Version 4.7 APSC-DV-002390 CAT II, APSC-DV-002400 CAT II, APSC-DV-002550 CAT I

[45] Standards Mapping - Security Technical Implementation Guide Version 4.8 APSC-DV-002390 CAT II, APSC-DV-002400 CAT II, APSC-DV-002550 CAT I

[46] Standards Mapping - Security Technical Implementation Guide Version 4.9 APSC-DV-002390 CAT II, APSC-DV-002400 CAT II, APSC-DV-002550 CAT I

[47] Standards Mapping - Security Technical Implementation Guide Version 4.10 APSC-DV-002390 CAT II, APSC-DV-002400 CAT II, APSC-DV-002550 CAT I

[48] Standards Mapping - Security Technical Implementation Guide Version 4.11 APSC-DV-002390 CAT II, APSC-DV-002400 CAT II, APSC-DV-002550 CAT I

[49] Standards Mapping - Security Technical Implementation Guide Version 4.1 APSC-DV-002390 CAT II, APSC-DV-002400 CAT II, APSC-DV-002550 CAT I

[50] Standards Mapping - Security Technical Implementation Guide Version 5.1 APSC-DV-002390 CAT II, APSC-DV-002400 CAT II, APSC-DV-002550 CAT I

[51] Standards Mapping - Security Technical Implementation Guide Version 5.2 APSC-DV-002390 CAT II, APSC-DV-002400 CAT II, APSC-DV-002550 CAT I

[52] Standards Mapping - Security Technical Implementation Guide Version 5.3 APSC-DV-002390 CAT II, APSC-DV-002400 CAT II, APSC-DV-002550 CAT I

[53] Standards Mapping - Security Technical Implementation Guide Version 6.1 APSC-DV-002390 CAT II, APSC-DV-002400 CAT II, APSC-DV-002550 CAT I

[54] Standards Mapping - Web Application Security Consortium Version 2.00 Denial of Service (WASC-10)

[55] Standards Mapping - Web Application Security Consortium 24 + 2 Denial of Service

desc.config.xml.weak_xml_schema_unbounded_occurrences