Computer Tampering in Illinois: Surprising Ways it Applies

 Posted on October 09, 2025 in Computer Crimes

When many people think of computer crimes, they imagine sketchy hackers cracking secure systems. Under the Computer Tampering Law (720 ILCS 5/17-51) in Illinois, however, the definition of computer crimes is significantly broader. The statute not only covers hacking into another’s computer system, but also such things as misuse of employer databases, "phishing" activities, altering digital records, and unauthorized access to another’s email.

Something as simple as logging into your spouse’s email account without permission or accessing workplace data outside of your job duties could potentially result in you facing felony charges. If you are facing charges under the Computer Tampering law in Illinois, you need a highly experienced Wheaton, IL criminal defense attorney who understands the technology and the law.  

An Overview of the Computer Tampering Law in Illinois

The Illinois statute for Computer Tampering prohibits "knowingly and without authorization" accessing a computer, program, or data, or introducing a virus or malware into another person’s or entity’s computer. It also includes falsifying email transmission information (often known as phishing or spoofing), and altering, deleting, or destroying data. The statute covers both private systems and government (state) systems.

What Are Some Common Situations That Could Lead to Computer Tampering Charges?

Some of the more common scenarios that could potentially lead to computer tampering charges include:

• During a divorce or custody battle, a spouse logs onto the other’s social media or email to find hidden assets or information about a relationship.
• An employee has a conflict with a supervisor, then accesses the HR database.
• A student accesses restricted school files to attempt to change his or her grades.
• A jealous boyfriend/girlfriend installs spyware or tracking software on another’s device.
• An individual uses fake email headers or phishing tactics to trick victims into sending money.

What are the Charges and Penalties for Computer Tampering in Illinois?

There is a range of charges and penalties for computer tampering, from a Class B misdemeanor to a Class 3 felony. The charges will be determined by whether real damage occurred, whether there was a clear intent to defraud or commit another crime, and whether the incident involved government or public utilities. For example:

• Accessing someone’s email or account without permission, when no damage results, is charged as a Class B misdemeanor with penalties of up to six months in jail and a maximum fine of $1,500.
• Accessing a work database outside job duties and attempting, but failing, to alter data is a Class A misdemeanor, with penalties of up to one year in jail and a maximum fine of $2,500.
• Altering, deleting, or damaging data, installing spyware, or phishing with a clear intent to defraud is charged as a Class 4 felony with penalties of one to three years in prison, and a maximum fine of $25,000.
• Tampering with government, public utility, or medical records with significant loss of data or other damages is a Class 3 felony, with penalties of two to five years in prison, and a maximum fine of $25,000.

Illinois Computer Tampering Law Goes Far Beyond Hacking

Under the Illinois Computer Tampering law, there is no need for sophisticated hacking or network intrusion. Even when a person knows another’s password, but accesses his or her sites without permission, charges of Computer Tampering could be filed. Many cases involve personal disputes or conflicts at work. Defenses to the crime can include actual permission, lack of intent, technical flaws in evidence collection, and overreach by prosecutors.

Contact a DuPage County, IL Computer Crimes Lawyer

Computer tampering cases are often highly technical, requiring expert witnesses in digital forensics. It is important that you consult with an experienced Wheaton, IL criminal defense attorney from Stephen A. Brundage early on in the process. Attorney Brundage’s law enforcement background, including experience as an investigator, instructor, evidence technician, and police officer, makes him eminently qualified to defend against criminal charges. He has practiced law in Illinois for over three decades. To schedule your free consultation, call 630-260-9647.