Computer users, companies, and organizations need to be vigilant in ensuring that they do not fall victim to cybercriminals; we all need to understand what the common signs of a computer system compromise are.
Many different steps can be taken by the attackers during their attempt to exploit your system, many of which can cause warning signs that can be noticed by the users.
Your Email Account Is Sending Out Spam
This is still an issue in 2021. If your pals tell you they've been receiving spam emails from you, likely, your account or PC has already been hacked. This typically occurs when malware infects your computer and can read your browser history.
Some Email Accounts Are Suspiciously Busy Or Have Changed Settings
Unknown or suspicious emails can mean a couple of things. Either you've been compromised and the hackers are using your address to send out spam, or the account has been hijacked by another person. In addition, if your email settings have been changed without your knowledge, that's also a huge warning sign that something is up.
Security Software Is Ineffective
If you run antivirus scans on your computer and find it comes back clean, but still have technical issues with programs shutting down unexpectedly, being unable to access files, etc., this means there may be a rootkit operating underneath it all. The best option? Restart in Safe Mode and perform a full system scan.
This can also indicate a router hijack which is typically the case if your email address has been compromised as well. In addition, you may want to consider changing your password as a precautionary measure.
Your Password Has been Changed
You may be a victim of malware if you have ever gotten an email from a website you've registered with informing you that your account password has been modified. This might be the result of downloads made online that weren't scanned before they were opened, and it doesn't even have to be something questionable in nature. Hackers can simply use software to monitor your keystrokes while you're typing in the password.
The Connection Appears Slow
If your connection is taking forever to load a web page, or if it's very sluggish, this can indicate that either your system has been compromised or data packets are being interrupted somewhere along the line. This could mean you have malware on your PC, someone is intercepting the traffic in and out of your computer, or there could be a rootkit operating and redirecting information to other servers.
The Network Capacity Is Reduced
If someone accesses your router and changes the settings, you will then experience lower bandwidth levels than usual because your connection can't run at top speed. Another sign that this has happened is when the DHCP lease time limit is set far too short for how often you're likely using it. If these kinds of things happen without your knowledge or permission, we'd recommend speaking with an IT professional about what's going on.
Your Webcam Light Turns On On Its Own
Rats are another source of problems. Your PC may be taken control of remotely by a malware program known as Remote Administration Tools (RAT). This tool is the source of many webcam recordings found on the Internet, including YouTube. Hackers can easily activate your camera and spy on you at their discretion, so keeping a close eye on this feature is advised.
Ransomware Makes You Think Your Computer Has Been Locked
Unknown parties may ask you to pay them money to "unlock" your PC after it has been compromised. Hackers typically use malware that places custom messages across the user's desktop or locks down specific drives until you pay up. You should never give in to these demands as they will only result in more money for the hackers and make them more likely to try their luck on you again.
Although this list is not exhaustive, it should give you an idea of some things that may be going on behind the scenes without your knowledge. Hackers can rack up huge bills by using your connection and making calls with premium numbers, and there's no telling what else they might do if given enough time to operate undetected.
It's also possible that somebody used a remote administration tool to take control of your system remotely, yet left no trace of their tracks once done. The best defense against these types of menaces is secure network management from a professional IT service provider.