界: Input Validation and Representation

入力の検証や表現の問題は、メタキャラクター、代替エンコーディング、数値表現などによって引き起こされます。セキュリティの問題は、入力を信頼することに起因します。この問題に含まれるのは、「Buffer Overflow」、「Cross-Site Scripting」攻撃、「SQL Injection」などです。

Denial of Service: StringBuilder

Java/JSP
Kotlin

Abstract

デフォルトのバッキング配列サイズで初期化された StringBuilder または StringBuffer インスタンスに信頼できないデータを追加すると、JVM がヒープメモリ領域を過剰に消費するようになる可能性があります。

Explanation

デフォルトのバッキング文字配列サイズ (16) で初期化された StringBuilder または StringBuffer インスタンスにユーザー制御のデータを追加すると、基礎となる配列をユーザーのデータに合わせてサイズ変更するときにアプリケーションが大量のヒープメモリを消費するようになる可能性があります。StringBuilder または StringBuffer インスタンスにデータが追加されると、インスタンスは、バッキング文字配列にデータを保存できる十分な空き領域があるかどうかを判断します。データが適合しない場合、StringBuilder または StringBuffer インスタンスは前の配列サイズの 2 倍以上の容量を持つ新しい配列を作成します。古い配列はガベージコレクトされるまでヒープ内に残ります。攻撃者はこの実装の詳細を利用して、Denial of Service (DoS) 攻撃を実行する可能性があります。

例 1: デフォルトのコンストラクタで初期化された StringBuilder インスタンスにユーザー制御のデータが追加されます。


    ...
    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 - DISA Control Correlation Identifier Version 2 CCI-001094, CCI-001310

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

[19] 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

[20] 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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

[43] Standards Mapping - Security Technical Implementation Guide Version 6.1 APSC-DV-002400 CAT II, APSC-DV-002530 CAT II

[44] 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)
    }
    ...