Trish Miller Network Security

Trish Miller Types of Attacks Attacks on the OSI & TCP/IP Model Attack Methods Prevention Switch Vulnerabilities and Hacking Cisco Routers Interesting links Objectives

Trish Miller Physical Access Attacks –Wiretapping –Server Hacking –Vandalism Dialog Attacks –Eavesdropping –Impersonation –Message Alteration Types of Attacks

Trish Miller Social Engineering –Opening Attachments –Password Theft –Information Theft Types of Attacks (Cont.) Penetration Attacks –Scanning (Probing) –Break-in –Denial of Service –Malware Viruses Worms

Trish Miller Risk Analysis of the Attack What is the cost if the attack succeeds? What is the probability of occurrence? What is the severity of the threat? What is the countermeasure cost? What is the value to protect the system Determine if the countermeasure should be implemented. Finally determine its priority.

Trish Miller OSI & TCP/IP Related Attacks

Trish Miller Session –Password theft –Unauthorized Access with Root permission Transport & Network: –Forged TCP/IP addresses –DoS Attacks OSI Model Related Attacks Application layer: –Attacks on web –Attacks are typically virus Presentation: –Cracking of encrypted transmissions by short encryption key

Trish Miller Data Link & Physical –Network Sniffers –Wire Taps –Trojan Horses –Malicious code OSI Model Related Attacks

Trish Miller Attacks Related to TCP Packet Port Number –Applications are identified by their Port numbers –Well-known ports (0-1023) HTTP=80, Telnet=23, FTP=21 for supervision, 20 for data transfer, SMTP=25 –Allows applications to be accessed by the root user

Trish Miller IP address spoofing –Change the source IP address –To conceal identity of the attacker –To have the victim think the packet comes from a trusted host –LAND attack Attacks Related to TCP Packet

Trish Miller Attacks Related to TCP Packet Port Number –Registered ports ( ) for any application –Not all operating systems uses these port ranges, although all use well-known ports

Trish Miller Attack Methods

Trish Miller Host Scanning Network Scanning Port Scanning Fingerprinting Attack Methods

Trish Miller Host Scanning –Ping range of IP addresses or use alternative scanning messages –Identifies victims –Types of Host scanning Ping Scanning TCP SYN/ACK attacks Attack Methods (Cont.)

Trish Miller Network Scanning –Discovery of the network infrastructure (switches, routers, subnets, etc.) –Tracert and applications similar identifies all routers along the route to a destination host Attack Methods (Cont.)

Trish Miller Port Scanning –Once a host is identified, scan all ports to find out if it is a server and what type it is –Two types: Server Port Scanning –TCP –UDP Client Port Scanning –NetBIOS –Ports 135 – 139 used for NetBIOS ports used for file and print services. –GRC.com a free website that scan your pc for open ports. Attack Methods (Cont.)

Trish Miller Fingerprinting –Discovers the host operating system and applications as well as the version Active (sends) Passive (listen) –Nmap does all major scanning methods Attack Methods (Cont.)

Trish Miller Denial-of-Service (DoS) Attacks –Attacks on availability –SYN flooding attacks overload a host or network with connection attempts –Stopping DoS attacks is very hard. Attack Methods (Cont.)

Trish Miller The Break-In –Password guessing –Take advantage of unpatched vulnerabilities –Session hijacking Attack Methods (Cont.)

Trish Miller Download rootkit via TFTP Delete audit log files Create backdoor account or Trojan backdoor programs After the Compromise

Trish Miller Weaken security Access to steal information, do damage Install malicious software (RAT, DoS zombie, spam relay, etc.) After the Compromise (Cont.)

Trish Miller Prevention

Trish Miller Preventions Stealth Scanning Access Control Firewalls Proxy Servers IPsec Security Policies DMZ Host Security

Trish Miller Noisiness of Attacks Exposure of the Attacker’s IP Address Reduce the rate of Attack below the IDS Threshold Scan Selective Ports Stealth Scanning

Trish Miller The goal of access control is to prevent attackers from gaining access, and stops them if they do. The best way to accomplish this is by: –Determine who needs access to the resources located on the server. –Decide the access permissions for each resource. –Implement specific access control policies for each resource. –Record mission critical resources. –Harden the server against attacks. –Disable invalid accounts and establish policies Access Control

Trish Miller Firewalls Firewalls are designed to protect you from outside attempts to access your computer, either for the purpose of eavesdropping on your activities, stealing data, sabotage, or using your machine as a means to launch an attack on a third party.

Trish Miller Firewalls (Cont.) Hardware –Provides a strong degree of protection from the outside world. –Can be effective with little or no setup –Can protect multiple systems Software –Better suite to protect against Trojans and worms. –Allows you to configure the ports you wish to monitor. It gives you more fine control. –Protects a single system.

Trish Miller Firewalls Can Prevent –Discovery Network Traceroute –Penetration Synflood Garbage UDP Ping TCP Ping Ping of Death

Trish Miller Proxy A proxy server is a buffer between your network and the outside world. Use an anonymous Proxy to prevent attacks.

Trish Miller IPSec Provides various security services for traffic at the IP layer These security services include –Authentication –Integrity –Confidentiality

Trish Miller IPsec overview - how IPsec helps ProblemHow IPsec helps Details Unauthorized system access Authentication, tamperproofing Defense in depth by isolating trusted from untrusted systems Targeted attacks of high- value servers Authentication, tamperproofing Locking down servers with IPsec. Examples: HR servers, Outlook® Web Access (OWA), DC replication EavesdroppingAuthentication, confidentiality Defense in depth against password or information gathering by untrusted systems Government guideline compliance Authentication, confidentiality Example: “All communications between financial servers must be encrypted.”

Trish Miller DMZ Image

Trish Miller Hardening Servers Cisco IOS Upgrades and Patches Unnecessary Services Network Monitoring tools Host Security

Trish Miller Switch Vulnerabilities and Hacking

Trish Miller Used to locate IP address, version, and model. Mass amounts of packets being sent can fake a crash Used to troubleshoot network, but should be disabled. CDP Protocol

Trish Miller Give users data by poisoning ARP cache of end node. MAC address used to determine destination. Device driver does not check. User can forge ARP datagram for man in the middle attack. ARP Poisoning

Trish Miller SNMP manages the network. Authentication is weak. Public and Private community keys are clear text. Uses UDP protocol which is prone to spoofing. Enable SNMPv3 without backwards compatibility. SNMP

Trish Miller Standard STP takes seconds to deal with a failure or Root bridge change. Purpose: Spanning Tree Attack reviews the traffic on the backbone. Spanning Tree Attacks

Trish Miller Only devices affected by the failure notice the change The attacker can create DoS condition on the network by sending BPDUs from the attacker. Spanning Tree Attacks

Trish Miller STEP 1: MAC flood the access switch STEP 2: Advertise as a priority zero bridge. Spanning Tree Attacks (Cont.)

Trish Miller Spanning Tree Attacks (Cont.) STEP 3: The attacker becomes the Root bridge! –Spanning Tree recalculates. –The backbone from the original network is now the backbone from the attacking host to the other switches on the network. Spanning Tree Attacks (Cont.)

Trish Miller Disabling STP can introduce another attack. BPDU Guard –Disables ports using portfast upon detection of a BPDU message on the port. –Enabled on any ports running portfast STP Attack Prevention

Trish Miller Root Guard –Prevents any ports that can become the root bridge due to their BPDU STP Attack Prevention

Trish Miller Cisco Content Switching Modules Cisco Content Switching Module with SSL CSM and CSM-S

Trish Miller Cisco Secure Desktop –3 major vulnerabilities Maintains information after an Internet browsing session. This occurs after an SSL VPN session ends. Evades the system via the system policies preventing logoff, this will allow a VPN connection to be activated. Allow local users to elevate their privileges. CDM

Trish Miller Prevention –Cisco has software to address the vulnerabilities. –There are workarounds available to mitigate the effects of some of these vulnerabilities.

Trish Miller Cisco Routers

Trish Miller Two potential issues with Cisco Routers –Problems with certain IOS software –SNMP Cisco Routers

Trish Miller Devices running Cisco IOS versions 12.0S, 12.2, 12.3 or 12.4 –Problem with the software –Confidential information can be leaked out –Software updates on the CISCO site can fix this problem

Trish Miller Virtual Private Networks Virtual connection 1 Virtual Connection 2

Trish Miller Virtual Private Networks Information leak Error Connection

Trish Miller Cisco uBR10012 series devices automatically enable SNMP read/write access Since there are no access restrictions on this community string, attackers can exploit this to gain complete control of the device

Trish Miller CISCO Router Attacking Computer By sending an SNMP set request with a spoofed source IP address the attacker will be able to get the Victim router to send him its configuration file.

Trish Miller CISCO Router Attacking Computer With this information, the remote computer will be able to have complete control over this router

Trish Miller Fixes- Software updates available on the CICSO site that will fix the Read/Write problem

Trish Miller Links n.problems.htmlhttp://insecure.org/sploits/l0phtcrack.lanma n.problems.html

Trish Miller References onid=2YYDWJHHX3FL2QSNDLPSKHSCJUNN2JVN?ar ticleID= &pgno=2http:// onid=2YYDWJHHX3FL2QSNDLPSKHSCJUNN2JVN?ar ticleID= &pgno= htmlhttp:// 998.html 02-convery-switches.pdfhttp:// 02-convery-switches.pdf switched-networks.htmlhttp:// switched-networks.html htmlhttp:// 47.html

Trish Miller