1 Introduction to Malcode, DoS Attack, Traceback, RFID Security Cliff C. Zou 03/02/06
2 Virus Infection Mechanisms Virus code in attachment Require user to click/execute attachment No vulnerability needed on target computer Exploit software vulnerability (e.g., outlook) Infect by simply checking Contain URL directing to malicious web servers Trick user to download/execute (e.g., patch) Could be a mini web server set up on sender
3 Why Users Keep Clicking Virus Attachment? protocol (SMTP) has no built-in security No encryption Easy to fake the “From: …” field Appear to come from your friends, admin,… Social engineering tricks Warning: your computer is infected! Fun video clip, photos, doc to share from friends
4 Virus Spreading Steps Obtain addresses Address book, web cache, … Search “mailto:...” in google, yahoo, etc (MyDoom) Send out virus Usually, use its own SMTP engine The host normally connects to an outgoing server for sending Many viruses avoid certain domain
5 Other -based Malware Spam Profit-driven Usually sent from compromised hosts Spyware (trojan) Adware Phishing Trick user to connect to a fake website Record user input of account information
6 Distributed Denial of Service (DDoS) Attack Send large amount of traffic to a server so that the server has no resource to serve normal users Attacking format: Consume target memory/CPU resource SYN flood (backscatter paper presented before) Database query… Congest target Internet connection Many sources attack traffic overwhelm target link Very hard to defend
7 Why hard to defined DDoS attack? Internet IP protocol has no built-in security No authentication of source IP SYN flood with faked source IP However, IP is true after connection is setup Servers are supposed to accept unsolicited service requests Lack of collaboration ways among Internet community How can you ask an ISP in another country to block certain traffic for you?
8 DoS spoofed attack defense: IP traceback Suppose a victim can call ISPs upstream to block certain traffic SYN flood: which traffic to block? IP traceback: Find out the real attacking host for SYN flood Based on large amount of attacking packets Need a little help from routers (packet marking)
9 Worm defense: Worm traceback Find who is the first to be infected Useful for enterprise network Find the security breach point afterwards Based on worm attacking flow
10 RFID Background RFID: radio-frequency identification Tiny computer chip with an antenna to transmit information to an RFID reader RFID tag in consumer market Store a unique ID number “Wireless” bar code Huge market profit in the future Cheap tags for most consumer products Different tags for vast applications
11 RFID Background Power issue Active: battery-powered, long range E-pass Passive: no battery, powered by radio signal from RFID reader Consumer tags (no crypto/authentication, cheap) ExxonMobil SpeedPass (crypto-enable, expensive) Memory issue Read-only (cheapest) Read/Write
12 Current approaches for Privacy Preservation Crypto/authentication: No resource available on cheap RFID tags Applicable on high-end RFID (e.g., SpeedPass) Attackers can use laptop/PDA to decrypt Kill tag (when in consumer’s hands): Kill all ID, or kill long-range ID Pro: simple, reliable (understandable to people) Con: non-reversible, no more service from RFID
13 Current approaches for Privacy Preservation Radio signal shield Pro: simple/understandable Con: suitable for a small range of tags Tags in wallet: credit card, currency Jam radio signal: (e.g., RFID blocker) Like denial-of-service to ID query from reader Con: a separate device, hard to configure deny service (intrusive)