Understand malware classifications because understanding how they spread is vital to their containment and removal.
A computer virus modifies executable files. When a victim executes a file, the virus is also executed. They are uncommon today and represent no more than 10% of all malware. Viruses are the only type of malware that infects files, making them especially hard to clean because they must be executed from a legitimate program. Antivirus programs will simply quarantine or delete the infected file.
Malicious worms often arrive as message attachments so if one person opens an infected email, the entire company could be infected in short order.
Worms are self-replicating. Take the case of the infamous Iloveyou worm: When it was launched, it hit nearly all email user in the world, overloading phone systems and brought down television networks.
What makes worms so devastating are their ability to spread without end-user action. They exploit files or programs to do the dirty work for them. The SQL Slammer worm used a vulnerability in Microsoft SQL to incur buffer overflows on every unpatched SQL server connected to the internet in about 10 minutes. That’s a speed record that still stands today.
Hackers have replaced worms with Trojan horses. They masquerade as legitimate programs but contain malicious instructions.
A Trojan must be executed by its victim in order to work. It usually comes in the form of an email or is inadvertently downloaded by a user while visiting an infected website. The most popular Trojan is the fake antivirus program which pops up claiming you’re infected. It then instructs you to run a program to clean your PC, allowing it to take root.
Trojans are hard to defend against and spread by tricking end-users, which makes patches, firewalls and other traditional defenses ineffective.
4. Hybrids or Stealth
Malware is now mostly a combination of malicious programs. It can include parts of Trojans, worms and viruses. In some cases, the malware program appears to the end-user as a Trojan, but once executed, it infects others over a network like a worm.
Malware programs are now considered rootkits or stealth. Malware tries to modify the operating system and take control while hiding from antimalware software.
Bots are a combination of Trojans and worms attempting to make exploited clients a part of a larger network. Bots have control servers that clients check into to receive instructions. Botnets range from a few thousand computers to huge networks with hundreds of thousands of systems.
Its a Malware program that encrypts your data and asks for cryptocurrency in exchange of the decryption key. Ransomware has crippled companies, hospitals, police departments, governments and even entire cities.
Ransomware programs are mostly Trojans. Once executed, it looks for and encrypts user files within minutes.
About a quarter of victims pay the ransom and around 30% do not even get their files decrypted. The only way to protect yourself is with offline backups of all critical files.
6. Fileless malware
Fileless malware comprises over 50% of malware attacks today. Its malware that does not use files or the file system. It spreads in memory or uses registry keys, APIs or scheduled tasks.
Fileless attacks exploits an existing program, becomes a sub-process or uses Microsoft’s PowerShell. This attack is harder to detect and stop.
Adware exposes the compromised end-user to unwanted malicious advertising. A common adware program might redirect a user’s browser searches to look-alike web pages that contain other product promotions.
Malvertising is the use of legitimate ad networks to deliver malware to unsuspecting users. Criminals pay to place an ad on a legit website. When a user clicks on the ad, code redirects them to a malicious website and installs malware on their computer. The malware embedded in an ad can execute itself automatically without any action from the user.
Criminals use malvertising to make money. It can deliver any type of money-making malware such as ransomware or crypto mining scripts.
Spyware is often used by parents to keep an eye on their children. But criminals also use spyware to log the keystrokes of victims and steal their passwords.
Finding and removing malware components is a complicated task. It’s easy to miss a component or delete vital ones accidentally. Furthermore, you won’t know if the malware has modified the system and made it totally untrustworthy.
To get it done right, you should call on Audit Solutions. Our well-trained professionals are experts in malware removal. Contact us today.