CIS 450 – Network Security Chapter 3 – Information Gathering

Attacker has to understand the environment he is going after

Steps for Gathering Information Find Out Initial Information Attacker has to have some initial information such as an IP address or domain name Open Source Information – company web site/related web sites Whois - s/index.jhtml s/index.jhtml Nslookup -

Find Out Address Range (or Subnet Mask) of Network Attacker wants to know is to make sure attack is concentrated on one, not several networks A larger address space might mean a larger company with better security ARIN (American Registry for Internet Numbers) - Traceroute – modifies the Time to Live (TTL) field to determine the path a packet takes through the network -

Find Active Machines Ping – finds active machines on a network Ping War – scan more than one machine at a time - l l

Find Open Ports or Access Points Port Scanners – runs through a series of ports to see which ones are open. TCP Connect Scan – tries to connect to each port on machine TCP SYN scan – stealthier than a connect scan FIN scan – Most systems do not log these packets ACK scan – gets around the firewall to scan an internal host Nmap War Dialers – programs for finding modems on a network THC-Scan -

Figure Out the Operating System Done by sending remote host unusual packets or packets that do not make sense Each OS handles these packets differently Queso Nmap

Figure Out Which Services Are Running on Each Port Knowing what specific service is running enables the attacker to look up exploits and launch known vulnerabilities against the service Default Port and OS – Based on common configuration and software attacker can make a best guess of what services are running on each port Telnet Vulnerability scanners – programs that can be run against a site that give a hacker a list of vulnerabilities on the target host

Map Out the Network Attacker maps out the network to figure out the best way to break in Traceroute – determines the path from source to destination Visual Ping Cheops -

Protection Whois Use a position title with a general number rather than a specific person List your phone number but make up a fictitious name and Run your own DNS server with split DNS Nslookup Minimize the records that appear in your DNS records Any IP address listed should be statically mapped through a firewall with only a specific port allowed through (e.g. mail server should be behind firewall with a non-routable address)

Protection ARIN Web Search Only use addresses that ARIN can trace for external devices such as routers and firewalls. All other devices should use a private address and should be behind a firewall Traceroute Use private addresses inside your firewall Ping Use private addresses inside your firewall

Protection Map the Network PortScan and Fingerprinting Have a firewall that properly blocks traffic and only allows traffic on specific ports to specific machines