Zennoxa Shield
Rules / Rust
SHIELD-RUST-004

Command injection via interpolated argument

criticalRustCWE-78CVSS 9.1

What it detects

Passing a format!-built string as a process argument can inject commands or flags.

How to fix

Pass fixed arguments as separate .arg() values; never build args from untrusted input.

Vulnerable — Shield flags thismain.rs
use std::process::Command;

fn convert_image(user_file: &str) -> std::io::Result<()> {
    let status = Command::new("convert")
        .arg(format!("--input={}", user_file))
        .arg("out.png")
        .status()?;
    println!("convert exited: {}", status);
    Ok(())
}
Fixed — scans cleanmain.rs
use std::process::Command;

fn convert_image(user_file: &str) -> std::io::Result<()> {
    let status = Command::new("convert")
        .arg("--input")
        .arg(user_file)
        .arg("out.png")
        .status()?;
    println!("convert exited: {}", status);
    Ok(())
}

Both snippets are verified against the shipped scanner: the vulnerable one triggers SHIELD-RUST-004, the fixed one does not.

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SHIELD-RUST-004: Command injection via interpolated argument — Zennoxa Shield