Someone you know can hack you just as easily as a stranger can by planting a logic bomb in your computer.
What is a logic bomb virus?
A logic bomb virus is a computer virus that contains a logic bomb, which is malicious code that triggers an attack when specific conditions are met. Positive conditions refer to something happening, like a program opening, while negative conditions refer to something not happening, like someone not logging in.
Logic bombs are often installed by someone with high-level access, such as a system administrator. Such a person can cause mayhem by setting up logic bombs on multiple systems and programming them to “blow up” simultaneously when a certain event occurs, like when an employee is removed from the company’s salary database.
Another name for a logic bomb is slag code, which refers to the manipulated code that makes an otherwise safe program harmful. Time bombs are a popular type of logic bomb, and sometimes the two terms are used interchangeably. Logic bombs are also sometimes called code bombs or cyber bombs.
Whatever name is used, a logic bomb’s method of attack is clear: lie dormant in infected software until triggered. Common attacks involve corrupting data, deleting files, and clearing out hard drives.
How does a logic bomb work?
The way a logic bomb works depends on the bombmaker. Every logic bomb is unique, which is why they’re difficult to track. They’re usually customized to be as undetectable as possible. Logic bombs are often dressed up to look like a typical computer virus, or inserted into other types of malware such as worms. Worms and viruses are different, but logic bombs don’t care about the distinction: they can cause destruction via either one.
The characteristics of a logic bomb virus
All logic bomb viruses contain logic bombs, and all logic bombs share the following characteristics:
- They lie dormant until triggered.
- They carry an unknown payload, which is the part of the code that performs the attack.
- They deliver the payload when a certain condition is met.
Among other things, a logic bomb can deliver its payload when:
- A specified amount of time elapses.
- A specific date occurs.
- A certain transaction is processed.
- A particular program opens.
- Someone (for example, an admin) fails to log in.
And a logic bomb’s potential payload may be designed to:
- Corrupt data.
- Wipe hard drives.
- Delete files.
- Siphon off funds.
- Gather sensitive data.
Logic bombs may be slow to reveal themselves, but very quickly they can explode into major problems.
Is a time bomb virus the same as a logic bomb virus?
Time bombs are a subspecies of logic bombs. A normal logic bomb goes off when a certain event occurs or a particular condition is met, such as a specific sequence of keystrokes. A time bomb is a ticking logic bomb programmed to execute at a specified time or date. In other words, a logic bomb needs to be stepped on, so to speak, to explode, while a time bomb will explode no matter what, unless it’s stopped.
“Time bomb malware” is sometimes used to refer to time bombs, though this is a bit of a misnomer. Just like logic bombs, time bombs hide inside various types of malware while not technically being malware themselves. A time bomb virus — also technically a misnomer — is nevertheless a term often used to refer to a virus carrying a time bomb.
Logic bomb and time bomb examples
Logic bombs can subtly change a snippet of code so it appears technically normal-looking to an automated system searching for threats, while being ultra-fishy to a human. In 2016, a programmer caused spreadsheets to malfunction at a branch of the Siemens corporation every few years, so that they had to keep hiring him back to fix the problem. In this case, the humans didn’t even suspect anything until a lucky coincidence forced the malicious code out into the open.
How to prevent logic bomb attacks
Hackers like packing logic bombs into viruses and malware, so general website safety is a solid first line of defense. By practicing good internet hygiene, you can keep your system clean.
As a second line of defense, get quality antivirus software that can detect logic bombs in real time and remove them from your system.