계: Input Validation and Representation

입력 검증 및 표현 문제는 메타 문자, 대체 인코딩 및 숫자 표현 때문에 발생합니다. 보안 문제는 입력을 신뢰하기 때문에 발생합니다. 문제로는 "Buffer Overflows", "Cross-Site Scripting" 공격, "SQL Injection", 그 외 여러 가지가 있습니다.

Denial of Service: StringBuilder

Java/JSP
Kotlin

Abstract

기본 백업 배열 크기로 초기화된 StringBuilder 또는 StringBuffer 인스턴스에 신뢰할 수 없는 데이터를 추가하면 JVM이 힙 메모리 공간을 과소비하게 될 수 있습니다.

Explanation

기본 백업 문자 배열 크기(16)로 초기화된 StringBuilder 또는 StringBuffer 인스턴스에 사용자 제어 데이터를 추가하면 응용 프로그램이 사용자의 데이터에 맞게 기본 배열의 크기를 조정하는 동안 대량의 힙 메모리를 소비하게 될 수 있습니다. 데이터가 StringBuilder 또는 StringBuffer 인스턴스에 추가되면 인스턴스는 백업 문자 배열에 데이터를 저장할 충분한 여유 공간이 있는지를 확인합니다. 데이터가 맞지 않는 경우 StringBuilder 또는 StringBuffer 인스턴스는 이전 배열 크기의 두 배 이상의 크기로 새 배열을 생성하지만 가비지가 수집되기 전까지 힙에 이전 배열이 남아 있습니다. 공격자는 이 구현 세부 정보를 사용하여 Denial of Service (DoS) 공격을 실행할 수 있습니다.

예제 1: 기본 생성자로 초기화된 StringBuilder 인스턴스에 사용자 제어 데이터가 추가됩니다.


    ...
    StringBuilder sb = new StringBuilder();
    final String lineSeparator = System.lineSeparator();
    String[] labels = request.getParameterValues("label");
    for (String label : labels) {
        sb.append(label).append(lineSeparator);
    }
    ...

References

[1] DOS-1: Beware of activities that may use disproportionate resources Oracle

[2] MSC05-J. Do not exhaust heap space CERT

[3] Standards Mapping - CIS Azure Kubernetes Service Benchmark 2

[4] Standards Mapping - CIS Amazon Elastic Kubernetes Service Benchmark 3.1

[5] Standards Mapping - CIS Amazon Web Services Foundations Benchmark 1

[6] Standards Mapping - CIS Google Kubernetes Engine Benchmark normal

[7] Standards Mapping - DISA Control Correlation Identifier Version 2 CCI-001094

[8] Standards Mapping - NIST Special Publication 800-53 Revision 4 SC-5 Denial of Service Protection (P1)

[9] Standards Mapping - NIST Special Publication 800-53 Revision 5 SC-5 Denial of Service Protection

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

[11] Standards Mapping - OWASP API 2023 API4 Unrestricted Resource Consumption

[12] Standards Mapping - OWASP Mobile 2024 M4 Insufficient Input/Output Validation

[13] Standards Mapping - OWASP Mobile Application Security Verification Standard 2.0 MASVS-CODE-4

[14] Standards Mapping - Payment Card Industry Data Security Standard Version 1.1 Requirement 6.5.1

[15] Standards Mapping - Payment Card Industry Data Security Standard Version 2.0 Requirement 6.5.1

[16] Standards Mapping - Payment Card Industry Data Security Standard Version 3.0 Requirement 6.5.1

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

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

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

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

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

[22] Standards Mapping - Payment Card Industry Software Security Framework 1.1 Control Objective 4.2 - Critical Asset Protection, Control Objective B.3.1 - Terminal Software Attack Mitigation, Control Objective B.3.1.1 - Terminal Software Attack Mitigation

[23] Standards Mapping - Payment Card Industry Software Security Framework 1.2 Control Objective 4.2 - Critical Asset Protection, Control Objective B.3.1 - Terminal Software Attack Mitigation, Control Objective B.3.1.1 - Terminal Software Attack Mitigation, Control Objective C.3.2 - Web Software Attack Mitigation

[24] Standards Mapping - SANS Top 25 2010 Risky Resource Management - CWE ID 754

[25] Standards Mapping - Security Technical Implementation Guide Version 3.1 APP3510 CAT I

[26] Standards Mapping - Security Technical Implementation Guide Version 3.4 APP3510 CAT I

[27] Standards Mapping - Security Technical Implementation Guide Version 3.5 APP3510 CAT I

[28] Standards Mapping - Security Technical Implementation Guide Version 3.6 APP3510 CAT I

[29] Standards Mapping - Security Technical Implementation Guide Version 3.7 APP3510 CAT I

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

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

[32] Standards Mapping - Security Technical Implementation Guide Version 4.1 APSC-DV-002400 CAT II

[33] Standards Mapping - Security Technical Implementation Guide Version 4.2 APSC-DV-002400 CAT II

[34] Standards Mapping - Security Technical Implementation Guide Version 4.3 APSC-DV-002400 CAT II

[35] Standards Mapping - Security Technical Implementation Guide Version 4.4 APSC-DV-002400 CAT II

[36] Standards Mapping - Security Technical Implementation Guide Version 4.5 APSC-DV-002400 CAT II

[37] Standards Mapping - Security Technical Implementation Guide Version 4.6 APSC-DV-002400 CAT II

[38] Standards Mapping - Security Technical Implementation Guide Version 4.7 APSC-DV-002400 CAT II

[39] Standards Mapping - Security Technical Implementation Guide Version 4.8 APSC-DV-002400 CAT II

[40] Standards Mapping - Security Technical Implementation Guide Version 4.9 APSC-DV-002400 CAT II

[41] Standards Mapping - Security Technical Implementation Guide Version 4.10 APSC-DV-002400 CAT II

[42] Standards Mapping - Security Technical Implementation Guide Version 4.11 APSC-DV-002400 CAT II

[43] Standards Mapping - Security Technical Implementation Guide Version 5.1 APSC-DV-002400 CAT II

[44] Standards Mapping - Security Technical Implementation Guide Version 5.2 APSC-DV-002400 CAT II

[45] Standards Mapping - Security Technical Implementation Guide Version 5.3 APSC-DV-002400 CAT II, APSC-DV-002530 CAT II

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

desc.dataflow.java.denial_of_service_stringbuilder

Abstract

Explanation


    ...
    val sb = StringBuilder()
    val labels = request.getParameterValues("label")
    for (label in labels) {
        sb.appendln(label)
    }
    ...