What if my computer is infected?

Unfortunately, it may happen occasionally that the antivirus installed in your computer with its latest updates is incapable of detecting a new virus, worm or a Trojan. Sadly but true: no antivirus protection software gives you a 100% guarantee of complete security. If your computer does get infected, you need to determine the fact of infection, identify the infected file and send it to the vendor whose product missed the malicious program and failed to protect your computer.

However, users on their own are typically unable to detect that their computer got infected unless aided by antivirus solutions. Many worms and Trojans typically do not reveal their presence in any way. By way of exception, some Trojans do inform the user directly that their computer has been infected – they may encrypt the user’s personal files so as to demand a ransom for the decryption utility. However, a Trojan typically installs itself secretly in the system, often employs special disguising methods and also covertly does its activity. So, the fact of infection can be detected by indirect evidence only.

Symptoms of infection

An increase in the outgoing web traffic is the general indication of an infection; this applies to both individual computers and corporate networks. If no users are working in the Internet in a specific time period (e.g. at night), but the web traffic continues, this could mean that somebody or someone else is active on the system, and most probably that is a malicious activity. In a firewall is configured in the system, attempts by unknown applications to establish Internet connections may be indicative of an infection. Numerous advertisement windows popping up while visiting web-sites may signal that an adware in present in the system. If a computer freezes or crashes frequently, this may be also related to a malware activity. Such malfunctions are more often accounted for by hardware or software malfunctions rather than a virus activity. However, if similar symptoms simultaneously occur on multiple or numerous computers on the network, accompanied by a dramatic increase in the internal traffic, this is very likely caused by a network worm or a backdoor Trojan spreading across the network.

An infection may be also indirectly evidenced by non-computer related symptoms, such as bills for telephone calls that nobody made or SMS messages that nobody sent. Such facts may indicate that a phone Trojan is active in the computer or the cell phone. If unauthorized access has been gained to your personal bank account or your credit card has bee used without your authorization, this may signal that a spyware has intruded into your system.

What to do

The first thing to do is make sure that the antivirus database is up-to-date and scan your computer. If this does not help, antivirus solutions from other vendors may do the job. Many manufacturers of anti-virus solutions offer free versions of their products for trial or one-time scanning – we recommend you to run one of these products on your machine. If it detects a virus or a Trojan, make sure you send a copy of the infected file to the manufacturer of the antivirus solution that failed to detect it. This will help this vendor faster develop protection against this threat and protect other users running this antivirus from getting infected.

If an alternative antivirus does not detect any malware, it is recommended that you disconnect your computer from the Internet or a local network, disable Wi-Fi connection and the modem, if any, before you start looking for the infected file(s). Do not use the network unless critically needed. Do not use web payment systems or internet banking services under any circumstances. Avoid referring to any personal or confidential data; do not use any web-based services that require your screen name and password.

How do I find an infected file?

Detecting a virus or Trojan in your computer in some cases may be a complex problem requiring a technical qualification; however, in other cases that may be a pretty straightforward task – this all depends on the degree of the malware complexity and the methods used to hide the malicious code embedded into the system. In the difficult cases when special methods (e.g. rootkit technologies) are employed to disguise and conceal the malicious code in the system, a non-professional may be unable to track down the infected file. This problem may require special utilities or actions, like connecting the hard disk to another computer or booting the system from a CD