电脑病毒与网路攻击简介.ppt

電腦病毒與網路攻擊簡介 蔡文能 tsaiwn@.tw 交通大學 資訊工程學系 Agenda What is a computer virus? Malware: Malicious software The story of virus and worm Type of viruses How viruses work? Introduction to Network Attack What is a virus? (1/2) 『電腦病毒』到底是什麼呢？ 它對人體會造成傷害嗎？ 用完電腦要洗手嗎？ What is a virus? (2/2) A virus is “a program that can infect other programs by modifying them to include a possibly evolved copy of itself.” - Fred Cohen A virus is a program that self-replicates Your computer runs all kinds of programs Virus is not data! Macro virus is NOT data either! 『電腦病毒』只是一段程式，它是一種會不斷「自我複製」及「感染」其它程式的電腦程式。 通常它都會寄存在可執行的檔案之中， 或者是軟、硬碟的開機磁區啟動部份。 電腦中毒現象 無緣無故經常會當機或自動關機 檔案長度增加 磁碟可利用的空間突然減少 電腦突然開不了機 程式執行速度突然變慢 程式開啟時間比平常久 出現莫名其妙的訊息、對話方框或聲音 可執行檔的檔案大小或日期改變了 記憶體內增加來路不明的常駐程式 Malware (惡意軟體) 1/2 Malware is the short form for Malicious Software. It implies any software instructions that were developed with the intention to cause harm. Some common examples of malware are worms, exploit code and trojan horses. (From SANS) Malware or malicious software is software designed to infiltrate or damage a computer system without the owners informed consent. It is a portmanteau of the words malicious and software. The expression is a general term used by computer professionals to mean a variety of forms of hostile, intrusive, or annoying software or program code. (From Wikipedia) Malware (惡意軟體) 2/2 Malicious code often masquerades as good software or attaches itself to good software Some malicious programs need host programs Trojan horses, logic bombs, viruses Others can exist and propagate independently Worms There are many infection vectors and propagation mechanisms Things that under Malware Computer Virus Trojan Horse Computer Worm Botnet/backdoor and Zombie Spyware /Adware Ken Thompson’s speech Ken Thompson’s 1983 Turing Award lecture Added a backdoor-opening Trojan to login program Anyone looking at source code would see this, so changed the compiler to add backdoor at compile-time Anyone looking