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Metadata

ID: java-security/avoid-null-cipher

Language: Java

Severity: Warning

Category: Security

Description

Do not use NullCipher as it does not transform the plaintext and the cipher text is identical to the text. Use real security measures for your application.

Learn More

Non-Compliant Code Examples

public class Main {
    public static main(String[] args) {
        Cipher doNothingCihper = new NullCipher();
        Cipher doNothingCihper2 = new javax.crypto.NullCipher();
    }
    @Override
    public void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        response.setContentType("text/html;charset=UTF-8");

        javax.servlet.http.Cookie[] theCookies = request.getCookies();

        String param = "noCookieValueSupplied";
        if (theCookies != null) {
            for (javax.servlet.http.Cookie theCookie : theCookies) {
                if (theCookie.getName().equals("BenchmarkTest00073")) {
                    param = java.net.URLDecoder.decode(theCookie.getValue(), "UTF-8");
                    break;
                }
            }
        }

        String bar;
        String guess = "ABC";
        char switchTarget = guess.charAt(1); // condition 'B', which is safe

        // Simple case statement that assigns param to bar on conditions 'A', 'C', or 'D'
        switch (switchTarget) {
            case 'A':
                bar = param;
                break;
            case 'B':
                bar = "bob";
                break;
            case 'C':
            case 'D':
                bar = param;
                break;
            default:
                bar = "bob's your uncle";
                break;
        }

        try {
            java.security.MessageDigest md = java.security.MessageDigest.getInstance("MD5");
            byte[] input = {(byte) '?'};
            Object inputParam = bar;
            if (inputParam instanceof String) input = ((String) inputParam).getBytes();
            if (inputParam instanceof java.io.InputStream) {
                byte[] strInput = new byte[1000];
                int i = ((java.io.InputStream) inputParam).read(strInput);
                if (i == -1) {
                    response.getWriter()
                            .println(
                                    "This input source requires a POST, not a GET. Incompatible UI for the InputStream source.");
                    return;
                }
                input = java.util.Arrays.copyOf(strInput, i);
            }
            md.update(input);

            byte[] result = md.digest();
            java.io.File fileTarget =
                    new java.io.File(
                            new java.io.File(org.owasp.benchmark.helpers.Utils.TESTFILES_DIR),
                            "passwordFile.txt");
            java.io.FileWriter fw =
                    new java.io.FileWriter(fileTarget, true); // the true will append the new data
            fw.write(
                    "hash_value="
                            + org.owasp.esapi.ESAPI.encoder().encodeForBase64(result, true)
                            + "\n");
            fw.close();
            response.getWriter()
                    .println(
                            "Sensitive value '"
                                    + org.owasp
                                            .esapi
                                            .ESAPI
                                            .encoder()
                                            .encodeForHTML(new String(input))
                                    + "' hashed and stored<br/>");

        } catch (java.security.NoSuchAlgorithmException e) {
            System.out.println("Problem executing hash - TestCase");
            throw new ServletException(e);
        }

        response.getWriter()
                .println(
                        "Hash Test java.security.MessageDigest.getInstance(java.lang.String) executed");
    }
}
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