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  <title>Potential command injection with Process.Start - Roslyn Security Guard</title>
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        <h2>Potential command injection with Process.Start</h2>
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<p>
    The dynamic value passed to the command execution should be validated.
</p>

<h3>Risk</h3>

<p>
    If a malicious user is able to controlled either the command FileName or Arguments, he might be able
    to execute unwanted commands or add unwanted argument.
    This behavior would not be possible if input parameter are validate against a whitelist of characters.
</p>

<h3>Vulnerable Code</h3>

<pre>
Process p = new Process();
p.StartInfo.FileName = "exportLegacy.exe";
p.StartInfo.Arguments = " -user " + input + " -role user";
p.Start();
</pre>

<h3>Solution</h3>

<pre>
Regex rgx = new Regex(@"^[a-zA-Z0-9]+$");
if(rgx.IsMatch(input)) {
    Process p = new Process();
    p.StartInfo.FileName = "exportLegacy.exe";
    p.StartInfo.Arguments = " -user " + input + " -role user";
    p.Start();
}
</pre>

<h3>References</h3>

<p>
<a href="https://www.owasp.org/index.php/Command_Injection">OWASP: Command Injection</a><br/>
<a href="https://www.owasp.org/index.php/Top_10_2013-A1-Injection">OWASP: Top 10 2013-A1-Injection</a><br/>
<a href="http://cwe.mitre.org/data/definitions/78.html">CWE-78: Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')</a>
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