ZShell Scripting Security

Security best practices for ZShell (Zsh) scripting to prevent unauthorized execution and exploitation.

Understanding ZShell Scripting Security

ZShell (Zsh) is a powerful UNIX shell widely used for automation, system administration, and scripting. While it offers advanced features over Bash, insecure Zsh scripting can lead to vulnerabilities such as command injection, privilege escalation, and data leaks.

Best Practices for ZShell Scripting Security

Sanitize User Input

Use read -r to safely read user input.
Validate and escape special characters before execution.

Avoid eval and source for Untrusted Data

Replace eval with safer alternatives like case statements or functions.
Only source scripts from trusted sources.

Secure Environment Variables

Restrict modifications to $PATH to prevent execution of malicious binaries.
Use export -n VAR to prevent variable inheritance in child processes.

Use Proper File Permissions

Assign least privilege access (chmod 700 script.sh) to sensitive scripts.

Limit Wildcard Expansion

Use quoted variables to prevent unintended globbing (e.g., "$var" instead of $var).

Enable Secure Shell Options

Set set -o noglob to disable wildcard expansion.
Use set -u to prevent the use of undefined variables.

Impact of Insecure ZShell Scripting

Remote Code Execution (RCE) – Attackers can exploit weak scripts to run arbitrary commands.
Data Leaks – Sensitive credentials or files may be exposed through improper logging.
Privilege Escalation – Poor permission handling can grant attackers root access.