Least Privilege Violation

ASDR Table of Contents

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Description
The elevated privilege level required to perform operations such as chroot should be dropped immediately after the operation is performed.

When a program calls a privileged function, such as chroot, it must first acquire root privilege. As soon as the privileged operation has completed, the program should drop root privilege and return to the privilege level of the invoking user.

Risk Factors
TBD

Examples
The following code calls chroot to restrict the application to a subset of the filesystem below APP_HOME in order to prevent an attacker from using the program to gain unauthorized access to files located elsewhere. The code then opens a file specified by the user and processes the contents of the file.

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

Constraining the process inside the application's home directory before opening any files is a valuable security measure. However, the absence of a call to setuid with some non-zero value means the application is continuing to operate with unnecessary root privileges. Any successful exploit carried out by an attacker against the application can now result in a privilege escalation attack because any malicious operations will be performed with the privileges of the superuser. If the application drops to the privilege level of a non-root user, the potential for damage is substantially reduced.

J2EE Misconfiguration: Weak Access Permissions
Permission to invoke EJB methods should not be granted to the ANYONE role.

If the EJB deployment descriptor contains one or more method permissions that grant access to the special ANYONE role, it indicates that access control for the application has not been fully thought through or that the application is structured in such a way that reasonable access control restrictions are impossible.

The following deployment descriptor grants ANYONE permission to invoke the Employee EJB's method named getSalary.

 ...		  ANYONE Employee getSalary   ...	

Related Attacks

 * Attack 1
 * Attack 2

Related Vulnerabilities

 * Broken Access Control
 * Failure to drop privileges when reasonable

Related Controls

 * Category:Access Control

Related Technical Impacts

 * Technical Impact 1
 * Technical Impact 2