Overview

Malware is an umbrella term for various types of malicious software. This term encompasses Viruses, Worms, Trojans, Adware, and more. Common symptoms of a malware infection include slow computer performance; difficulty registering or accessing the network; the inability to run software updates or anti-virus software, and unexplained pop-up warnings, errors, or ads. This article will review some basic information about various types of malware, how to recognize it, and what to do about it.

Student-owned computers suspected of having any kind of malware infection can be dropped off free of charge at the ITS Helpdesk from 8 am–5 pm Monday–Friday.

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What is it?

• Malicious program that attaches itself to a legitimate file or program (the Host).
• Infects machine when host file is run or opened.
• Typically cannot run itself, needs human intervention.

What does it do?

• Harmless as presenting “I’m here!”
• Dangerous as deleting files.
• Trigger immediately or wait for instructions or wait for a specific date.

How does it spread?

• Via any files that move between computers (e.g. email).
• Once on machine, looks for files to infect.
• Relies on user transmission of those files.

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What is it?

• Disguises itself as useful software or legitimate files.
• Typically cannot run itself, needs human intervention.

What does it do?

• Harmless as changing icons on your desktop.
• Dangerous as opening “back doors” to the machine.

How does it spread?

• Purely human intervention; “invited” onto system.
• Cannot replicate itself.
• Opening files or images…

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What is it?

• Malicious program that spreads itself without a Host.
• Designed to duplicate and spread via network.

What does it do?

• Can cause network problems (heavy traffic).
• Acts of vandalism are rare but possible.
• Will often open “back doors” to the machine.

How does it spread?

• Replicates itself on the same machine.
• Capable of spreading itself often via email.
• Via network, often through their own back doors.

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What is it?

• Normally legitimately installed software.
• Free software paid for by the advertisements (to recoup development costs).

What does it do?

• Downloads and/or displays ads on your machine.
• Provides a free version of software.

How does it spread?

• Downloaded and installed deliberately by user.
• May note sites you visit and display corresponding advertisements (SpyWare).

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What is it?

• Any program that monitors your behavior: e.g. surfing habits, sites visited.

How it spreads?

• Piggy-backs on other software; not as a virus as it’s often intentional.
• Can operate like a Trojan e.g. fake security software.
• Tricks users into bypassing security.

What it does?

• Record and deliver info you enter online.
• Can install software, redirect browser.

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What is it?

• Program(s) which hide deep on your system.
• Replaces system files which then hide processes.

How it spreads?

• Spread as Viruses or Trojans (not Worms).
• Rarely spreads itself any further once infected.

What does it do?

• Allows unauthorized access to your machine.
• Sniffers, keyloggers, zombie computer.

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What is it?

• Spyware that records personal data.
• Refers to a collection of machines.

How it spreads?

• Spread via Trojans or like Worms
• Scan local environment to find vulnerable machines

What does it do?

• Very low-key – it wants to remain hidden.
• Gathers information and relays it (e.g. banking).
• Used for identity theft, compromise online accts.

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What is it?

• Attempt to gain personal information such as passwords or account information fraudulently e.g. Email masquerading as bank representative.

How?

• Majority of attempts happen via email.
• Also Instant Messaging, Social Networking.
• Refer to websites that look like the original.

What does it do?

• Gain access to account, or identity theft

Bad or suspicious links, especially in HTML email, what a link says might not be where it’s actually going.

Dangerous attachments: Attachments can contain the malware itself, which might or might not be caught by antivirus tools. As a rule of thumb, don’t open one unless you know exactly who sent it and what it contains.

Phishing:  Tricking a user into giving away personal or financial information

Out of date software: may have vulnerabilities which can be exploited. Be sure to apply all patches and updates.

Browser plugins: are popular targets because they are easy to install and often don’t get updated.

Operating system: are the primary line of attach for malware developers. Run security patches and updates regularly.

Legitimate websites can contain dangerous links or harmful code:

• Facebook (stolen passwords)
• Forums, blogs, etc.
• Security holes in webservers
• Bad advertisements / popups

Search engines: can be tricked or "seeded" with malicious sites

Some attacks can happen without any interaction from you:

• Sometimes called drive-by downloads
• Usually associated with a browser or plugin vulnerability

While it is true that there are far fewer infections for Mac computers, Macs are not invulnerable and can be infected. In addition, infected files may be transferred via Mac as, for example, email attachments. Don't assume you don't need to be protected or be careful just because you're on a Mac!