界: Encapsulation

封裝是要劃定清楚的界限。在網頁瀏覽器中，這可能意味著確保您的行動程式碼不會被其他行動程式碼濫用。在伺服器上，這可能意味著區分經過驗證的資料與未經驗證的資料、區分一個使用者的資料與另一個使用者的資料，或區分允許使用者查看的資料與不允許查看的資料。

File Based Cross-Zone Scripting

Abstract

載入可在應用程式內容中執行不可信賴之 Script 的檔案是很危險的。

Explanation

當滿足以下條件時，會發生 File Based Cross Zone Scripting：

1. 載入會讓 Script 在應用程式內執行的檔案。

2. 載入的 Script 是視為執行中應用程式的相同來源。

若這兩個條件均符合，即會導致一系列攻擊，特別是如果其他方根據資訊是否來自應用程式內部來判定是否可信賴。

範例 1：以下程式碼使用 Android WebView 以便在本地載入檔案：


...
myWebView.loadUrl("file:///android_asset/www/index.html");
...

在 Example 1 中，Android WebView 轉譯器會將所有透過 loadUrl() (具有開頭為「file://」的 URL) 載入的程式碼視為位於同一來源。

在從檔案載入時，攻擊者透過以下幾種典型方式來利用 File Based Cross-Zone Scripting 弱點：
- 本地檔案由其他攻擊者所控制，該攻擊者會將 Script 插入檔案。
這取決於檔案權限、檔案位置或檔案可能的儲存位置及載入位置的競賽條件 (會有一個用於執行修改的時間窗口)。

- 檔案可能會召喚外部資源。
當載入的檔案從外部資源擷取 Script 時，可能會發生此情況。

範例 2：以下程式碼會查看外部來源以確定應該執行的 JavaScript。


  <script src="http://www.example.com/js/fancyWidget.js"></script>

在 Example 2 中，使用不安全的通訊協定會讓惡意動作執行者修改產生的指令碼。或者，可能會執行其他攻擊以將機器重新路由到攻擊者的站台。

- 載入的檔案可能包含 Cross-site scripting 弱點。
如果載入的檔案可插入程式碼，則插入的程式碼可在應用程式內容中執行。沒有必要非要插入 JavaScript，只需插入 HTML 亦可允許塗改或 Denial of Service 攻擊。

References

[1] Erika Chin and David Wagner Bifocals: Analyzing WebView Vulnerabilities in Android Applications

[2] Standards Mapping - Common Weakness Enumeration CWE ID 79, CWE ID 80

[3] Standards Mapping - Common Weakness Enumeration Top 25 2019 [2] CWE ID 079

[4] Standards Mapping - Common Weakness Enumeration Top 25 2020 [1] CWE ID 079

[5] Standards Mapping - Common Weakness Enumeration Top 25 2021 [2] CWE ID 079

[6] Standards Mapping - Common Weakness Enumeration Top 25 2022 [2] CWE ID 079

[7] Standards Mapping - Common Weakness Enumeration Top 25 2023 [2] CWE ID 079

[8] Standards Mapping - Common Weakness Enumeration Top 25 2024 [1] CWE ID 079

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

[10] Standards Mapping - FIPS200 SI

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

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

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

[14] Standards Mapping - OWASP Application Security Verification Standard 4.0 5.3.3 Output Encoding and Injection Prevention Requirements (L1 L2 L3), 5.3.6 Output Encoding and Injection Prevention Requirements (L1 L2 L3)

[15] Standards Mapping - OWASP Mobile 2014 M7 Client Side Injection

[16] Standards Mapping - OWASP Mobile Application Security Verification Standard 2.0 MASVS-CODE-4, MASVS-PLATFORM-2

[17] Standards Mapping - OWASP Top 10 2004 A4 Cross Site Scripting

[18] Standards Mapping - OWASP Top 10 2007 A1 Cross Site Scripting (XSS)

[19] Standards Mapping - OWASP Top 10 2010 A2 Cross-Site Scripting (XSS)

[20] Standards Mapping - OWASP Top 10 2013 A3 Cross-Site Scripting (XSS)

[21] Standards Mapping - OWASP Top 10 2017 A7 Cross-Site Scripting (XSS)

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

[23] Standards Mapping - Payment Card Industry Data Security Standard Version 1.1 Requirement 6.5.4

[24] Standards Mapping - Payment Card Industry Data Security Standard Version 1.2 Requirement 6.3.1.1, Requirement 6.5.1

[25] Standards Mapping - Payment Card Industry Data Security Standard Version 2.0 Requirement 6.5.7

[26] Standards Mapping - Payment Card Industry Data Security Standard Version 3.0 Requirement 6.5.7

[27] Standards Mapping - Payment Card Industry Data Security Standard Version 3.1 Requirement 6.5.7

[28] Standards Mapping - Payment Card Industry Data Security Standard Version 3.2 Requirement 6.5.7

[29] Standards Mapping - Payment Card Industry Data Security Standard Version 3.2.1 Requirement 6.5.7

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

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

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

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

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

[35] Standards Mapping - SANS Top 25 2009 Insecure Interaction - CWE ID 079

[36] Standards Mapping - SANS Top 25 2010 Insecure Interaction - CWE ID 079

[37] Standards Mapping - SANS Top 25 2011 Insecure Interaction - CWE ID 079

[38] Standards Mapping - Security Technical Implementation Guide Version 3.1 APP3510 CAT I, APP3580 CAT I

[39] Standards Mapping - Security Technical Implementation Guide Version 3.4 APP3510 CAT I, APP3580 CAT I

[40] Standards Mapping - Security Technical Implementation Guide Version 3.5 APP3510 CAT I, APP3580 CAT I

[41] Standards Mapping - Security Technical Implementation Guide Version 3.6 APP3510 CAT I, APP3580 CAT I

[42] Standards Mapping - Security Technical Implementation Guide Version 3.7 APP3510 CAT I, APP3580 CAT I

[43] Standards Mapping - Security Technical Implementation Guide Version 3.9 APP3510 CAT I, APP3580 CAT I

[44] Standards Mapping - Security Technical Implementation Guide Version 3.10 APP3510 CAT I, APP3580 CAT I

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

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

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

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

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

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

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

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

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

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

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

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

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

[58] Standards Mapping - Security Technical Implementation Guide Version 5.3 APSC-DV-002560 CAT I

[59] Standards Mapping - Security Technical Implementation Guide Version 6.1 APSC-DV-002560 CAT I

[60] Standards Mapping - Web Application Security Consortium Version 2.00 Cross-Site Scripting (WASC-08)

[61] Standards Mapping - Web Application Security Consortium 24 + 2 Cross-Site Scripting

desc.semantic.java.file_based_cross_zone_scripting

Abstract

載入可在應用程式有權限的內容中執行不可信賴之 Script 的本機檔案是很危險的。

Explanation

滿足以下條件時，會發生 File Based Cross Zone Scripting：

1. 載入了會讓 Script 在應用程式內執行的檔案。

2. 載入的 Script 被視為具有與執行中應用程式 (file://) 相同的來源。

若這兩個條件均符合，則可能會導致一系列攻擊，特別是如果其他方根據資訊是否來自應用程式內部來判定是否可信賴。

範例 1：以下程式碼使用 UIWebView.loadRequest(_:) 方法載入本機檔案：


...
NSURL *url = [[NSBundle mainBundle] URLForResource: filename withExtension:extension]; 
[webView loadRequest:[[NSURLRequest alloc] initWithURL:url]];
...

在 Example 1 中，WebView 引擎會將所有透過 UIWebView.loadRequest(_:) (具有開頭為 file:// 的 URL) 載入的程式碼視為位於有權限的本機檔案來源。

在從檔案載入時，攻擊者透過以下幾種典型方式來利用 File-Based Cross-Zone Scripting 弱點：

- 本機檔案可能受攻擊者控制。例如，攻擊者可能會將檔案傳送給其受害者，然後受害者繼續在易受攻擊的應用程式 (例如：雲端儲存應用程式) 上儲存該檔案
- 本地檔案由其他攻擊者所控制，該攻擊者會將 Script 注入檔案。這取決於檔案權限、檔案位置或檔案可能的儲存位置及載入位置的競賽條件 (會有一個用於執行修改的時間窗口)。
- 檔案可能會召喚外部資源。當載入的檔案從外部資源擷取 Script 時，可能會發生此情況。
- 載入的檔案可能包含 Cross-site scripting 弱點。如果正在載入的檔案包含注入的程式碼，則此程式碼可能會在您的應用程式內容中執行。注入的程式碼不需要為 JavaScript 程式碼，因為注入的 HTML 亦可允許塗改或 Denial of Service 攻擊。

如果攻擊者控制的檔案是透過 file:// URL 從本機載入，則相同來源策略 (Same Origin Policy) 將允許此檔案中的 Script 存取相同來源的任何其他檔案，這會讓攻擊者存取包含敏感資訊的任何本機檔案。

References

[1] Same-origin policy for file: URIs Mozilla

[2] Old Habits Die Hard: Cross-Zone Scripting in Dropbox & Google Drive Mobile Apps IBM

[3] loadHTMLString(_:baseURL:) API documentation Apple

[4] loadRequest(_:) API documentation Apple

[5] Standards Mapping - Common Weakness Enumeration CWE ID 79, CWE ID 80

[6] Standards Mapping - Common Weakness Enumeration Top 25 2019 [2] CWE ID 079

[7] Standards Mapping - Common Weakness Enumeration Top 25 2020 [1] CWE ID 079

[8] Standards Mapping - Common Weakness Enumeration Top 25 2021 [2] CWE ID 079

[9] Standards Mapping - Common Weakness Enumeration Top 25 2022 [2] CWE ID 079

[10] Standards Mapping - Common Weakness Enumeration Top 25 2023 [2] CWE ID 079

[11] Standards Mapping - Common Weakness Enumeration Top 25 2024 [1] CWE ID 079

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

[13] Standards Mapping - FIPS200 SI

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

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

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

[17] Standards Mapping - OWASP Application Security Verification Standard 4.0 5.3.3 Output Encoding and Injection Prevention Requirements (L1 L2 L3), 5.3.6 Output Encoding and Injection Prevention Requirements (L1 L2 L3)

[18] Standards Mapping - OWASP Mobile 2014 M7 Client Side Injection

[19] Standards Mapping - OWASP Mobile Application Security Verification Standard 2.0 MASVS-CODE-4, MASVS-PLATFORM-2

[20] Standards Mapping - OWASP Top 10 2004 A4 Cross Site Scripting

[21] Standards Mapping - OWASP Top 10 2007 A1 Cross Site Scripting (XSS)

[22] Standards Mapping - OWASP Top 10 2010 A2 Cross-Site Scripting (XSS)

[23] Standards Mapping - OWASP Top 10 2013 A3 Cross-Site Scripting (XSS)

[24] Standards Mapping - OWASP Top 10 2017 A7 Cross-Site Scripting (XSS)

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

[26] Standards Mapping - Payment Card Industry Data Security Standard Version 1.1 Requirement 6.5.4

[27] Standards Mapping - Payment Card Industry Data Security Standard Version 1.2 Requirement 6.3.1.1, Requirement 6.5.1

[28] Standards Mapping - Payment Card Industry Data Security Standard Version 2.0 Requirement 6.5.7

[29] Standards Mapping - Payment Card Industry Data Security Standard Version 3.0 Requirement 6.5.7

[30] Standards Mapping - Payment Card Industry Data Security Standard Version 3.1 Requirement 6.5.7

[31] Standards Mapping - Payment Card Industry Data Security Standard Version 3.2 Requirement 6.5.7

[32] Standards Mapping - Payment Card Industry Data Security Standard Version 3.2.1 Requirement 6.5.7

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

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

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

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

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

[38] Standards Mapping - SANS Top 25 2009 Insecure Interaction - CWE ID 079

[39] Standards Mapping - SANS Top 25 2010 Insecure Interaction - CWE ID 079

[40] Standards Mapping - SANS Top 25 2011 Insecure Interaction - CWE ID 079

[41] Standards Mapping - Security Technical Implementation Guide Version 3.1 APP3510 CAT I, APP3580 CAT I

[42] Standards Mapping - Security Technical Implementation Guide Version 3.4 APP3510 CAT I, APP3580 CAT I

[43] Standards Mapping - Security Technical Implementation Guide Version 3.5 APP3510 CAT I, APP3580 CAT I

[44] Standards Mapping - Security Technical Implementation Guide Version 3.6 APP3510 CAT I, APP3580 CAT I

[45] Standards Mapping - Security Technical Implementation Guide Version 3.7 APP3510 CAT I, APP3580 CAT I

[46] Standards Mapping - Security Technical Implementation Guide Version 3.9 APP3510 CAT I, APP3580 CAT I

[47] Standards Mapping - Security Technical Implementation Guide Version 3.10 APP3510 CAT I, APP3580 CAT I

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

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

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

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

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

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

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

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

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

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

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

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

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

[61] Standards Mapping - Security Technical Implementation Guide Version 5.3 APSC-DV-002560 CAT I

[62] Standards Mapping - Security Technical Implementation Guide Version 6.1 APSC-DV-002560 CAT I

[63] Standards Mapping - Web Application Security Consortium Version 2.00 Cross-Site Scripting (WASC-08)

[64] Standards Mapping - Web Application Security Consortium 24 + 2 Cross-Site Scripting

desc.dataflow.objc.file_based_cross_zone_scripting

Abstract

載入可在應用程式有權限的內容中執行不可信賴之 Script 的本機檔案是很危險的。

Explanation


...
let url = Bundle.main.url(forResource: filename, withExtension: extension)
self.webView!.load(URLRequest(url:url!))
...