Serializable Class Containing Sensitive Data

Description

Serializable classes are effectively open classes since data cannot be hidden in them. Classes that do not explicitly deny serialization can be serialized by any other class, which can then in turn use the data stored inside it.

Demonstrations

The following examples help to illustrate the nature of this weakness and describe methods or techniques which can be used to mitigate the risk.

Note that the examples here are by no means exhaustive and any given weakness may have many subtle varieties, each of which may require different detection methods or runtime controls.

Example One

This code creates a new record for a medical patient:

class PatientRecord {
  private String name;
  private String socialSecurityNum;
  public Patient(String name,String ssn) {
    this.SetName(name);
    this.SetSocialSecurityNumber(ssn);
  }
}

This object does not explicitly deny serialization, allowing an attacker to serialize an instance of this object and gain a patient's name and Social Security number even though those fields are private.

See Also