Potential time of check time of use vulnerability (chown)

Description

Usage of the `chown` function call hints at a potential Time Of Check Time Of Use (TOCTOU) vulnerability. An attacker may be able to modify the file being specified by the `chmod` function prior to the `chown` function being called. Since `chown` will resolve symbolic links, an attacker may be able to exploit this fact to have files outside of their control modified. It is recommended that the `fchown` or the `lchown` functions be used instead.

Examples

Insecure Code

chown("/path/to/file", uid, gid);

Secure Code

fchown(fd, uid, gid);

Remediation

Replace `chown` with `fchown` or `lchown` to prevent TOCTOU vulnerabilities. Ensure the opened file descriptor is pointing to the correct file or directory prior to executing `fchown` or any other file-based operations.

Rule Details

Field	Value
ID	CODE-0608
Category	AccessControl
Severity	MEDIUM
CWE	CWE-362
Confidence	HIGH
Impact	MEDIUM
Likelihood	MEDIUM
Exploitability	MODERATE
Tags	TOCTOU, file permissions
OWASP	A5:2017-Broken Access Control, A01:2021-Broken Access Control

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