Usage of bad hex conversion on digest array

• Rule ID: java_lang_bad_hex_conversion
• Languages: java
• Source: bad_hex_conversion.yml

Description

Your application is using Integer.toHexString for converting a digest array buffer into a hexadecimal string, which may lead to incorrect representations.

Remediations

• Do not use Integer.toHexString for converting digest arrays to hexadecimal strings due to the risk of inaccuracies.

  String hexString = Integer.toHexString(byteValue); // unsafe

• Do use java.util.HexFormat for accurate hexadecimal conversion in Java 17 and above.

  MessageDigest sha256Digest = MessageDigest.getInstance("SHA-256");
  sha256Digest.update("hello world".getBytes(StandardCharsets.UTF_8));
  byte[] output = sha256Digest.digest();
  
  HexFormat hex = HexFormat.of();
  String hexString = hex.formatHex(output);

• Do consider using javax.xml.bind.DatatypeConverter.printHexBinary for Java versions prior to 17 as an alternative for accurate hex conversion.

References

• DatatypeConverter

Associated CWE

• CWE-704: Incorrect Type Conversion or Cast

Configuration

To skip this rule during a scan, use the following flag

bearer scan /path/to/your-project/ --skip-rule=java_lang_bad_hex_conversion

To run only this rule during a scan, use the following flag

bearer scan /path/to/your-project/ --only-rule=java_lang_bad_hex_conversion