CWE-250: Execution with Unnecessary Privileges

When a program or component operates under an account or security context with excessive rights, errors in input handling, program invocation, or access control can reach more resources than intended. The excess authority can bypass normal operating-system or environmental checks and turn otherwise limited flaws into unauthorized data access, code or command execution, resource modification, or service disruption. The issue can arise during implementation, architecture and design, including AI/ML agent designs that grant components more authority than the user intends, and operation.

This is a base-level, simple weakness in which a component performs work in a security context stronger than necessary. The excess authority may be introduced by design, implementation, or operation, and can make other problems, including privilege-dropping errors or privilege chaining, more severe. The record is not language-specific and also identifies Python, AI/ML, and mobile platforms; AI/ML is marked as often applicable.

Excess privileges can let an attacker access any resources permitted by those privileges. Consequences include gaining privileges or assuming an identity, executing unauthorized code or commands, reading application data, and causing a denial of service by crashing, exiting, or restarting services. Running as root or Administrator can disable normal security checks, and pre-existing weaknesses can become exploitable when they occur in the elevated context.

• Minimize privileges: Run each component with the lowest privileges required for its tasks. Use isolated, task-specific accounts where possible, rather than broad accounts such as a database administrator.
• Separate privileged functionality: Centralize and isolate operations that require extra privileges. Raise privileges as late as possible and drop them as soon as possible. Protect every communication channel that can reach privileged code, including secondary administrative sockets.
• Validate exposed input: Apply strict input validation to any privileged code exposed to users. If extra privileges are unavoidable, identify the minimum required file, network, and other permissions, explicitly allow only those actions, and perform extensive validation and canonicalization.
• Verify privilege dropping: Confirm that privilege-dropping operations actually succeed, since environmental protection mechanisms can cause them to fail.
• Harden deployment: Run the software under the United States Government Configuration Baseline or an equivalent hardening guide to reduce the deployed attack surface and risk.

Manual analysis can identify this weakness through penetration testing, threat modeling, and interactive tools. For black-box assessment, monitor the process during login, inspect library and system calls that raise or drop privileges, and check access to resources restricted from ordinary users; this is useful without source code but mainly covers system-resource privilege issues, not application-level authorization rules.

Static approaches include comparing binary or bytecode with the permission manifest, binary or bytecode weakness analysis, disassembly followed by manual review, manual source-code review, focused source spot checks, source-code weakness analyzers, and context-configured analyzers. Additional approaches include configuration checking, permission-manifest analysis, host-based vulnerability scanners, host application interface scanners, and architecture or design review using IEEE 1028 inspection, formal methods, correct-by-construction methods, and attack modeling. The record rates manual source review, binary or bytecode comparison with the permission manifest, and architecture or design review methods as highly effective or very effective; several other methods are identified as providing partial coverage.

The following observed cases are representative examples, not an exhaustive list:

• CVE-2007-4217: an FTP client runs with setuid privileges and contains a buffer overflow; for clients that do not need extra privileges, the comparable overflow would not be a security vulnerability.
• CVE-2008-1877: a privileged program invokes another program with the same privileges, enabling arbitrary file reads.
• CVE-2007-5159 and CVE-2007-3931: the operating system or an installation script incorrectly assigns setuid privileges to programs, allowing users to gain privileges.
• CVE-2008-4638: a highly privileged application processes a restricted file selected by the user, and a parsing error discloses the file contents.
• CVE-2008-0162: a program fails to drop privileges before invoking another program, enabling code execution.
• CVE-2008-0368: a setuid root program permits arbitrary file creation through a command-line argument.
• CVE-2020-3812: a mail program runs as root and does not drop privileges before accessing a file, allowing an attacker to infer whether a root-only file exists through a symbolic link.
• CVE-2003-0908: Help functionality is launched with raised privileges, allowing command execution through a Windows message and the Open File dialog.