Least Privilege Violation

C/C++

Abstract

那些需要執行如 chroot() 操作的被提升的權限等級，應該在操作後馬上被丟棄。

Explanation

當程式呼叫權限函數 (比如 chroot()) 時，它必須先取得 root 權限。當權限操作完成後，程式應該馬上丟棄 root 權限並且回傳呼叫它的使用者權限等級。
範例 1：以下程式碼會呼叫 chroot() 將應用程式限制到 APP_HOME 下的檔案系統子集，這是為了防止攻擊者使用程式對位於別處的檔案進行未經授權的存取。然後程式碼就會開啟使用者指定的檔案並處理檔案目錄。


...
chroot(APP_HOME);
chdir("/");

FILE* data = fopen(argv[1], "r+");
...

在打開任何檔案之前，把應用程式的權限限制在 home 目錄內是相當安全的方法。然而，缺少使用一些非零值對函數 setuid() 的呼叫，意味著應用程式仍然繼續在使用沒有必要的 root 權限進行操作。只要攻擊者成功利用應用程式，就會引發權限提升攻擊，因為所有的惡意操作都將以超級使用者的權限來執行。如果應用程式把權限等級降低為非 root 使用者，那麼潛在的破壞立即會下降許多。

References

[1] A. Chuvakin Using Chroot Securely

[2] Standards Mapping - Common Weakness Enumeration CWE ID 272

[3] Standards Mapping - Common Weakness Enumeration Top 25 2023 [22] CWE ID 269

[4] Standards Mapping - Common Weakness Enumeration Top 25 2024 [15] CWE ID 269

[5] Standards Mapping - DISA Control Correlation Identifier Version 2 CCI-000381, CCI-002233, CCI-002235

[6] Standards Mapping - General Data Protection Regulation (GDPR) Access Violation

[7] Standards Mapping - NIST Special Publication 800-53 Revision 4 AC-6 Least Privilege (P1), CM-7 Least Functionality (P1)

[8] Standards Mapping - NIST Special Publication 800-53 Revision 5 AC-6 Least Privilege, CM-7 Least Functionality

[9] Standards Mapping - OWASP Application Security Verification Standard 4.0 1.4.3 Access Control Architectural Requirements (L2 L3), 1.4.3 Access Control Architectural Requirements (L2 L3), 10.2.2 Malicious Code Search (L2 L3)

[10] Standards Mapping - OWASP Mobile 2014 M5 Poor Authorization and Authentication

[11] Standards Mapping - OWASP Mobile 2024 M3 Insecure Authentication/Authorization

[12] Standards Mapping - OWASP Mobile Application Security Verification Standard 2.0 MASVS-AUTH-1

[13] Standards Mapping - Payment Card Industry Data Security Standard Version 1.2 Requirement 7.1.1

[14] Standards Mapping - Payment Card Industry Data Security Standard Version 2.0 Requirement 7.1.1

[15] Standards Mapping - Payment Card Industry Data Security Standard Version 3.0 Requirement 7.1.2

[16] Standards Mapping - Payment Card Industry Data Security Standard Version 3.1 Requirement 7.1.2

[17] Standards Mapping - Payment Card Industry Data Security Standard Version 3.2 Requirement 7.1.2

[18] Standards Mapping - Payment Card Industry Data Security Standard Version 3.2.1 Requirement 7.1.2

[19] Standards Mapping - Payment Card Industry Data Security Standard Version 4.0 Requirement 7.2.2

[20] Standards Mapping - Payment Card Industry Data Security Standard Version 4.0.1 Requirement 7.2.2

[21] Standards Mapping - Payment Card Industry Software Security Framework 1.0 Control Objective 5.4 - Authentication and Access Control

[22] Standards Mapping - Payment Card Industry Software Security Framework 1.1 Control Objective 5.4 - Authentication and Access Control

[23] Standards Mapping - Payment Card Industry Software Security Framework 1.2 Control Objective 5.4 - Authentication and Access Control, Control Objective C.2.3 - Web Software Access Controls

[24] Standards Mapping - Security Technical Implementation Guide Version 3.1 APP3500 CAT II

[25] Standards Mapping - Security Technical Implementation Guide Version 3.4 APP3500 CAT II

[26] Standards Mapping - Security Technical Implementation Guide Version 3.5 APP3500 CAT II

[27] Standards Mapping - Security Technical Implementation Guide Version 3.6 APP3500 CAT II

[28] Standards Mapping - Security Technical Implementation Guide Version 3.7 APP3500 CAT II

[29] Standards Mapping - Security Technical Implementation Guide Version 3.9 APP3500 CAT II

[30] Standards Mapping - Security Technical Implementation Guide Version 3.10 APP3500 CAT II

[31] Standards Mapping - Security Technical Implementation Guide Version 4.2 APSC-DV-000500 CAT II, APSC-DV-000510 CAT I, APSC-DV-001500 CAT II

[32] Standards Mapping - Security Technical Implementation Guide Version 4.3 APSC-DV-000500 CAT II, APSC-DV-000510 CAT I, APSC-DV-001500 CAT II

[33] Standards Mapping - Security Technical Implementation Guide Version 4.4 APSC-DV-000500 CAT II, APSC-DV-000510 CAT I, APSC-DV-001500 CAT II

[34] Standards Mapping - Security Technical Implementation Guide Version 4.5 APSC-DV-000500 CAT II, APSC-DV-000510 CAT I, APSC-DV-001500 CAT II

[35] Standards Mapping - Security Technical Implementation Guide Version 4.6 APSC-DV-000500 CAT II, APSC-DV-000510 CAT I, APSC-DV-001500 CAT II

[36] Standards Mapping - Security Technical Implementation Guide Version 4.7 APSC-DV-000500 CAT II, APSC-DV-000510 CAT I, APSC-DV-001500 CAT II

[37] Standards Mapping - Security Technical Implementation Guide Version 4.8 APSC-DV-000500 CAT II, APSC-DV-000510 CAT I, APSC-DV-001500 CAT II

[38] Standards Mapping - Security Technical Implementation Guide Version 4.9 APSC-DV-000500 CAT II, APSC-DV-000510 CAT I, APSC-DV-001500 CAT II

[39] Standards Mapping - Security Technical Implementation Guide Version 4.10 APSC-DV-000500 CAT II, APSC-DV-000510 CAT I, APSC-DV-001500 CAT II

[40] Standards Mapping - Security Technical Implementation Guide Version 4.11 APSC-DV-000500 CAT II, APSC-DV-000510 CAT I, APSC-DV-001500 CAT II

[41] Standards Mapping - Security Technical Implementation Guide Version 4.1 APSC-DV-000500 CAT II, APSC-DV-000510 CAT I, APSC-DV-001500 CAT II

[42] Standards Mapping - Security Technical Implementation Guide Version 5.1 APSC-DV-000500 CAT II, APSC-DV-000510 CAT I, APSC-DV-001500 CAT II

[43] Standards Mapping - Security Technical Implementation Guide Version 5.2 APSC-DV-000500 CAT II, APSC-DV-000510 CAT I, APSC-DV-001500 CAT II

[44] Standards Mapping - Security Technical Implementation Guide Version 5.3 APSC-DV-000500 CAT II, APSC-DV-000510 CAT I, APSC-DV-001500 CAT II

[45] Standards Mapping - Security Technical Implementation Guide Version 6.1 APSC-DV-000500 CAT II, APSC-DV-000510 CAT I, APSC-DV-001500 CAT II

[46] Standards Mapping - Web Application Security Consortium Version 2.00 Insufficient Authorization (WASC-02)

[47] Standards Mapping - Web Application Security Consortium 24 + 2 Insufficient Authorization

desc.controlflow.cpp.least_privilege_violation