界: Environment
本节包括的所有内容均与源代码无关，但对所创建产品的安全性仍然至关重要。因为本节涉及的问题与源代码没有直接关系，所以我们将它与其他章节分开。
PHP Misconfiguration: Missing open_basedir Entry
Abstract
赋予 PHP 程序对整个文件系统的访问权限可能会使攻击者读取、写入或创建本不允许访问的文件。
Explanation
如果提供
若无法使用
尽管
此类攻击的漏洞窗口是执行访问检查到打开文件之间的这段时间。即使连续执行调用，现代操作系统也不能保证进程挂起 CPU 之前执行的代码量。攻击者可通过多种技术延长机会窗口的长度，以便更容易地利用漏洞；然而，即使窗口很小，漏洞利用尝试也可以简单地重复一遍又一遍，直到成功。
open_basedir 配置选项，该配置选项会尝试阻止 PHP 程序对 php.ini 中指定的目录树之外的文件进行操作。如果未使用 open_basedir 选项指定目录，则在 PHP 下运行的程序可以全面访问本地文件系统上的任意文件，这样攻击者将能够读取、写入或创建本不应该访问的文件。若无法使用
open_basedir 指定一组限制性目录，很可能为攻击者利用其他漏洞提供便利。尽管
open_basedir 选项可从整体上增强安全性，但此实现方法会面临争用情况，有些时候攻击者还可能借此绕过限制 [2]。从 PHP 执行访问权限检查到打开文件这段时间存在检查时间、使用时间 (TOCTOU) 争用情况。如同其他语言文件系统的争用情况一样，攻击者可以利用此争用情况，将通过访问控制检查的文件的符号链接替换为其他未通过检查的符号链接，从而获得对受保护文件的访问权限。此类攻击的漏洞窗口是执行访问检查到打开文件之间的这段时间。即使连续执行调用，现代操作系统也不能保证进程挂起 CPU 之前执行的代码量。攻击者可通过多种技术延长机会窗口的长度，以便更容易地利用漏洞；然而，即使窗口很小，漏洞利用尝试也可以简单地重复一遍又一遍，直到成功。
References
[1] M. Achour et al. PHP Manual
[2] Stefan Esser PHP open_basedir Race Condition Vulnerability
[3] open_basedir Confusion
[4] Artur Maj Securing PHP
[5] Emmanuel Dreyfus Securing Systems with Chroot
[6] Standards Mapping - Common Weakness Enumeration CWE ID 284
[7] Standards Mapping - DISA Control Correlation Identifier Version 2 CCI-000213, CCI-002165
[8] Standards Mapping - FIPS200 AC
[9] Standards Mapping - General Data Protection Regulation (GDPR) Indirect Access to Sensitive Data
[10] Standards Mapping - NIST Special Publication 800-53 Revision 4 AC-3 Access Enforcement (P1)
[11] Standards Mapping - NIST Special Publication 800-53 Revision 5 AC-3 Access Enforcement
[12] Standards Mapping - OWASP API 2023 API8 Security Misconfiguration
[13] Standards Mapping - OWASP Application Security Verification Standard 4.0 1.4.2 Access Control Architectural Requirements (L2 L3), 1.4.4 Access Control Architectural Requirements (L2 L3)
[14] Standards Mapping - OWASP Mobile 2014 M5 Poor Authorization and Authentication
[15] Standards Mapping - OWASP Top 10 2004 A2 Broken Access Control
[16] Standards Mapping - OWASP Top 10 2007 A10 Failure to Restrict URL Access
[17] Standards Mapping - OWASP Top 10 2010 A8 Failure to Restrict URL Access
[18] Standards Mapping - OWASP Top 10 2013 A5 Security Misconfiguration
[19] Standards Mapping - OWASP Top 10 2017 A6 Security Misconfiguration
[20] Standards Mapping - OWASP Top 10 2021 A05 Security Misconfiguration
[21] Standards Mapping - Payment Card Industry Data Security Standard Version 1.1 Requirement 6.5.2, Requirement 7.2
[22] Standards Mapping - Payment Card Industry Data Security Standard Version 1.2 Requirement 6.5.10, Requirement 7.2
[23] Standards Mapping - Payment Card Industry Data Security Standard Version 2.0 Requirement 6.5.8, Requirement 7.2
[24] Standards Mapping - Payment Card Industry Data Security Standard Version 3.0 Requirement 6.5.8, Requirement 7.2
[25] Standards Mapping - Payment Card Industry Data Security Standard Version 3.1 Requirement 6.5.8, Requirement 7.2
[26] Standards Mapping - Payment Card Industry Data Security Standard Version 3.2 Requirement 6.5.8, Requirement 7.2
[27] Standards Mapping - Payment Card Industry Data Security Standard Version 3.2.1 Requirement 6.5.8, Requirement 7.2
[28] Standards Mapping - Payment Card Industry Data Security Standard Version 4.0 Requirement 6.2.4, Requirement 7.3.2
[29] Standards Mapping - Payment Card Industry Data Security Standard Version 4.0.1 Requirement 6.2.4, Requirement 7.3.2
[30] Standards Mapping - Payment Card Industry Software Security Framework 1.0 Control Objective 5.4 - Authentication and Access Control
[31] Standards Mapping - Payment Card Industry Software Security Framework 1.1 Control Objective 5.4 - Authentication and Access Control
[32] 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
[33] Standards Mapping - Security Technical Implementation Guide Version 3.1 APP3480.1 CAT II
[34] Standards Mapping - Security Technical Implementation Guide Version 3.4 APP3480.1 CAT I
[35] Standards Mapping - Security Technical Implementation Guide Version 3.5 APP3480.1 CAT I
[36] Standards Mapping - Security Technical Implementation Guide Version 3.6 APP3480.1 CAT I
[37] Standards Mapping - Security Technical Implementation Guide Version 3.7 APP3480.1 CAT I
[38] Standards Mapping - Security Technical Implementation Guide Version 3.9 APP3480.1 CAT I
[39] Standards Mapping - Security Technical Implementation Guide Version 3.10 APP3480.1 CAT I
[40] Standards Mapping - Security Technical Implementation Guide Version 4.2 APSC-DV-000460 CAT I, APSC-DV-000470 CAT II
[41] Standards Mapping - Security Technical Implementation Guide Version 4.3 APSC-DV-000460 CAT I, APSC-DV-000470 CAT II
[42] Standards Mapping - Security Technical Implementation Guide Version 4.4 APSC-DV-000460 CAT I, APSC-DV-000470 CAT II
[43] Standards Mapping - Security Technical Implementation Guide Version 4.5 APSC-DV-000460 CAT I, APSC-DV-000470 CAT II
[44] Standards Mapping - Security Technical Implementation Guide Version 4.6 APSC-DV-000460 CAT I, APSC-DV-000470 CAT II
[45] Standards Mapping - Security Technical Implementation Guide Version 4.7 APSC-DV-000460 CAT I, APSC-DV-000470 CAT II
[46] Standards Mapping - Security Technical Implementation Guide Version 4.8 APSC-DV-000460 CAT I, APSC-DV-000470 CAT II
[47] Standards Mapping - Security Technical Implementation Guide Version 4.9 APSC-DV-000460 CAT I, APSC-DV-000470 CAT II
[48] Standards Mapping - Security Technical Implementation Guide Version 4.10 APSC-DV-000460 CAT I, APSC-DV-000470 CAT II
[49] Standards Mapping - Security Technical Implementation Guide Version 4.11 APSC-DV-000460 CAT I, APSC-DV-000470 CAT II
[50] Standards Mapping - Security Technical Implementation Guide Version 4.1 APSC-DV-000460 CAT I, APSC-DV-000470 CAT II
[51] Standards Mapping - Security Technical Implementation Guide Version 5.1 APSC-DV-000460 CAT I, APSC-DV-000470 CAT II
[52] Standards Mapping - Security Technical Implementation Guide Version 5.2 APSC-DV-000460 CAT I, APSC-DV-000470 CAT II
[53] Standards Mapping - Security Technical Implementation Guide Version 5.3 APSC-DV-000460 CAT I, APSC-DV-000470 CAT II
[54] Standards Mapping - Security Technical Implementation Guide Version 6.1 APSC-DV-000460 CAT I, APSC-DV-000470 CAT II
[55] Standards Mapping - Security Technical Implementation Guide Version 6.2 APSC-DV-000460 CAT I, APSC-DV-000470 CAT II
[56] Standards Mapping - Web Application Security Consortium Version 2.00 Application Misconfiguration (WASC-15)
desc.config.php.php_misconfiguration_open_basedir