Reino: Security Features

Segurança de software não é o mesmo que software de segurança. Aqui, estamos interessados em tópicos como autenticação, controle de acesso, confidencialidade, criptografia e gestão de privilégios.

Least Privilege Violation

Abstract
O nível de privilégio elevado necessário para realizar operações como chroot() deve ser reduzido imediatamente após a conclusão da operação.
Explanation
Quando um programa chamar uma função privilegiada, como chroot(), ele primeiro deverá adquirir o privilégio de root. Assim que a operação privilegiada for concluída, o programa deverá reduzir o privilégio de root e retornar ao nível de privilégio do usuário responsável pela invocação.
Exemplo: O código a seguir chama chroot() para restringir o aplicativo a um subconjunto do sistema de arquivos abaixo de APP_HOME para impedir que um invasor utilize o programa para obter acesso não autorizado a arquivos localizados em outros lugares. Em seguida, o código abre um arquivo especificado pelo usuário e processa o conteúdo desse arquivo.


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

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


Restringir o processo no diretório base do aplicativo antes de abrir qualquer arquivo consiste em medida de segurança valiosa. No entanto, a ausência de uma chamada para setuid() com um valor diferente de zero significa que o aplicativo continua a operar com privilégios de root desnecessários. Qualquer exploração bem-sucedida realizada por um invasor contra o aplicativo pode agora resultar em um ataque de escalonamento de privilégios, já que qualquer operação mal-intencionada será executada com os privilégios do superusuário. Se o aplicativo reduzir o nível de privilégio de um usuário não root, o potencial de danos será substancialmente reduzido.
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