Least Privilege Violation

C/C++

Abstract

程序应该在操作结束后立即丢弃执行诸如 chroot() 一类的操作所需要的提高了的权限。

Explanation

当程序调用一个受权限控制的函数时，比如 chroot()，它必须先获取 root 权限。当受权限控制的操作完成后，程序应该马上丢弃 root 权限并且返回调用它的用户权限等级。
示例：以下的代码调用了 chroot() 函数，将应用程序限制在 APP_HOME 下的 file system 的子集中，以防止攻击者通过程序访问位于其他地方的未经授权的文件。然后，代码打开一个由用户指定的文件并处理文件的内容。


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

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

在打开文件之前，把应用程序的操作限制在主目录之内是一个相对安全的方法。然而，不使用一些非零值对函数 setuid() 进行调用，意味着应用程序仍在使用没有必要的 root 权限进行操作。任何由攻击者对应用程序实施的成功盗取都会导致发生权限扩大的攻击，因为所有的恶意操作都将以超级用户的权限执行。如果应用程序把权限等级降低到一个非 root 用户，则会显著减少很多潜在的破坏。

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 - DISA Control Correlation Identifier Version 2 CCI-000381, CCI-002233, CCI-002235

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

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

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

[8] 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)

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

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

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

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

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

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

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

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

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

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

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

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

[21] 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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

desc.controlflow.cpp.least_privilege_violation