界: Input Validation and Representation

輸入驗證和表示法問題是由中繼字元、替代編碼和數值表示法引起的。信任輸入會導致安全問題。問題包括：「Buffer Overflows」、「Cross-Site Scripting」攻擊、「SQL Injection」及其他許多問題。

Server-Side Template Injection

Abstract

使用者控制的資料可當作範本引擎的範本，可讓攻擊者存取範本內容，並在某些情況下，於應用程式伺服器上插入和執行任意程式碼。

Explanation

範本引擎可用於透過動態資料轉譯內容。此內容資料一般受使用者控制，由範本格式化以產生網頁、電子郵件等。透過使用程式碼建構 (例如條件、循環等) 處理內容資料，範本引擎允許將強大的語言運算式用於範本中以轉譯動態內容。如果攻擊者能夠控制要轉譯的範本，便能插入將洩漏內容資料的運算式，甚至在伺服器上執行任意指令。

範例 1：以下範例顯示如何從 HTTP 要求擷取範本並加以轉譯。


// Set up the context data
VelocityContext context = new VelocityContext();
context.put( "name", user.name );

// Load the template
String template = getUserTemplateFromRequestBody(request);
RuntimeServices runtimeServices = RuntimeSingleton.getRuntimeServices();
StringReader reader = new StringReader(template);
SimpleNode node = runtimeServices.parse(reader, "myTemplate");
template = new Template();
template.setRuntimeServices(runtimeServices);
template.setData(node);
template.initDocument();

// Render the template with the context data
StringWriter sw = new StringWriter();
template.merge( context, sw );

Example 1 使用 Velocity 做為範本引擎。對於該引擎，攻擊者可提交下列範本以在伺服器上執行任意指令：


$name.getClass().forName("java.lang.Runtime").getRuntime().exec(<COMMAND>)

References

[1] Server-Side Template Injection: RCE for the modern webapp

[2] Standards Mapping - Common Weakness Enumeration CWE ID 95

[3] Standards Mapping - Common Weakness Enumeration Top 25 2019 [18] CWE ID 094

[4] Standards Mapping - Common Weakness Enumeration Top 25 2020 [17] CWE ID 094

[5] Standards Mapping - Common Weakness Enumeration Top 25 2022 [25] CWE ID 094

[6] Standards Mapping - Common Weakness Enumeration Top 25 2023 [23] CWE ID 094

[7] Standards Mapping - Common Weakness Enumeration Top 25 2024 [11] CWE ID 094

[8] Standards Mapping - DISA Control Correlation Identifier Version 2 CCI-002754

[9] Standards Mapping - FIPS200 SI

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

[11] Standards Mapping - NIST Special Publication 800-53 Revision 4 SI-10 Information Input Validation (P1)

[12] Standards Mapping - NIST Special Publication 800-53 Revision 5 SI-10 Information Input Validation

[13] Standards Mapping - OWASP Application Security Verification Standard 4.0 5.2.4 Sanitization and Sandboxing Requirements (L1 L2 L3), 5.2.5 Sanitization and Sandboxing Requirements (L1 L2 L3), 5.2.8 Sanitization and Sandboxing Requirements (L1 L2 L3), 5.3.6 Output Encoding and Injection Prevention Requirements (L1 L2 L3)

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

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

[16] Standards Mapping - OWASP Top 10 2004 A6 Injection Flaws

[17] Standards Mapping - OWASP Top 10 2007 A2 Injection Flaws

[18] Standards Mapping - OWASP Top 10 2010 A1 Injection

[19] Standards Mapping - OWASP Top 10 2013 A1 Injection

[20] Standards Mapping - OWASP Top 10 2017 A1 Injection

[21] Standards Mapping - OWASP Top 10 2021 A03 Injection

[22] Standards Mapping - Payment Card Industry Data Security Standard Version 1.1 Requirement 6.5.6

[23] Standards Mapping - Payment Card Industry Data Security Standard Version 1.2 Requirement 6.3.1.1, Requirement 6.5.2

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

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

[26] Standards Mapping - Payment Card Industry Data Security Standard Version 3.1 Requirement 6.5.1

[27] Standards Mapping - Payment Card Industry Data Security Standard Version 3.2 Requirement 6.5.1

[28] Standards Mapping - Payment Card Industry Data Security Standard Version 3.2.1 Requirement 6.5.1

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

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

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

[32] 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

[33] 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

[34] Standards Mapping - SANS Top 25 2009 Insecure Interaction - CWE ID 116

[35] Standards Mapping - Security Technical Implementation Guide Version 3.1 APP3510 CAT I, APP3570 CAT I

[36] Standards Mapping - Security Technical Implementation Guide Version 3.4 APP3510 CAT I, APP3570 CAT I

[37] Standards Mapping - Security Technical Implementation Guide Version 3.5 APP3510 CAT I, APP3570 CAT I

[38] Standards Mapping - Security Technical Implementation Guide Version 3.6 APP3510 CAT I, APP3570 CAT I

[39] Standards Mapping - Security Technical Implementation Guide Version 3.7 APP3510 CAT I, APP3570 CAT I

[40] Standards Mapping - Security Technical Implementation Guide Version 3.9 APP3510 CAT I, APP3570 CAT I

[41] Standards Mapping - Security Technical Implementation Guide Version 3.10 APP3510 CAT I, APP3570 CAT I

[42] Standards Mapping - Security Technical Implementation Guide Version 4.2 APSC-DV-002560 CAT I

[43] Standards Mapping - Security Technical Implementation Guide Version 4.3 APSC-DV-002560 CAT I

[44] Standards Mapping - Security Technical Implementation Guide Version 4.4 APSC-DV-002560 CAT I

[45] Standards Mapping - Security Technical Implementation Guide Version 4.5 APSC-DV-002560 CAT I

[46] Standards Mapping - Security Technical Implementation Guide Version 4.6 APSC-DV-002560 CAT I

[47] Standards Mapping - Security Technical Implementation Guide Version 4.7 APSC-DV-002560 CAT I

[48] Standards Mapping - Security Technical Implementation Guide Version 4.8 APSC-DV-002560 CAT I

[49] Standards Mapping - Security Technical Implementation Guide Version 4.9 APSC-DV-002560 CAT I

[50] Standards Mapping - Security Technical Implementation Guide Version 4.10 APSC-DV-002560 CAT I

[51] Standards Mapping - Security Technical Implementation Guide Version 4.11 APSC-DV-002560 CAT I

[52] Standards Mapping - Security Technical Implementation Guide Version 4.1 APSC-DV-002560 CAT I

[53] Standards Mapping - Security Technical Implementation Guide Version 5.1 APSC-DV-002560 CAT I

[54] Standards Mapping - Security Technical Implementation Guide Version 5.2 APSC-DV-002560 CAT I

[55] Standards Mapping - Security Technical Implementation Guide Version 5.3 APSC-DV-002530 CAT II, APSC-DV-002560 CAT I

[56] Standards Mapping - Security Technical Implementation Guide Version 6.1 APSC-DV-002530 CAT II, APSC-DV-002560 CAT I

[57] Standards Mapping - Web Application Security Consortium Version 2.00 Improper Input Handling (WASC-20)

desc.dataflow.java.server_side_template_injection

Abstract

使用者控制的資料可當作範本引擎的範本，可讓攻擊者存取範本內容，並在某些情況下，於應用程式伺服器上插入和執行任意程式碼。

Explanation

範本引擎可用於透過動態資料轉譯內容。此內容資料一般受使用者控制，由範本格式化以產生網頁、電子郵件等。範本引擎透過使用程式碼建構 (例如條件、循環等) 處理內容資料，可將強大的語言運算式用於範本中以轉譯動態內容。如果攻擊者可控制要轉譯的範本，便能插入運算式來洩漏內容資料，甚至在伺服器上執行任意指令。

範例 1：以下範例顯示如何從 HTTP 要求擷取範本並加以轉譯。


app.get('/', function(req, res){
    var template = _.template(req.params['template']);
    res.write("<html><body><h2>Hello World!</h2>" + template() + "</body></html>");
});

Example 1 使用 Underscore.js 做為 Node.js 應用程式內的範本引擎。對於該引擎，攻擊者可提交下列範本以在伺服器上執行任意指令：


<% cp = process.mainModule.require('child_process');cp.exec(<COMMAND>); %>