Malware

Viruses E-mail Virus Worms Trojan Horses Spyware

– Keystroke Loggers Adware

Viruses

Segments of programs that attach to other programs

When an “infected” program is run, the virus is run

The virus seeks uninfected software and infects it Viruses can be spread to other computers through

shared media or e-mail Can attach to Word documents, spreadsheets –

anything which can have code Famous “boot-sector” virus on floppy disks

E-mail viruses

Programs that are attached to e-mail messages When run attach themselves to programs May use address book to send messages to others

using victim's return address May look like image files or text documents

Virus Defenses

Anti-virus software Can check against a list of virus “signatures” Can look for suspicious activity Must be updated regularly

Don't run programs from untrusted sources Digital signatures Shrink-wrapped software is not immune to viruses Informed users

Worms

Program that propagate themselves through a network

When a computer is infected, the program runs and seeks out other computes to infect

Often exploits bugs in software, especially network and web applications

May use password attacks Famous example: Morris worm of 1998

Worm Defenses

Keep software up-to-date, especially with security patches

Firewall Monitoring software Use secure passwords Informed users

Trojan Horse

A program that appears to do one thing, but really does another

May do both – legitimate and illegitimate functions

Often found in games from untrusted sources

Defenses: Don't download from untrusted sources Use source code

Spyware

Programs that spy on you May collect personal information Can be used for identity theft Keystroke loggers monitor whatever is typed on

the keyboard Information is sent via the internet to hacker's

machine

Warheads

Once control is gained of a computer, there are various malicious tasks that can be done:

botnets steal personal information change information shut down virus protection and other safety

features allow remote access to computer damage hardware