Skip to main content

Types of Layer 2/Switch Security Attacks, and Mitigation steps in Brief

Security Attacks against Switches or at Layer 2 can be grouped in four major Categories as follows:
1. MAC layer attacks
2. VLAN attacks
3. Spoofing attacks
4. Attacks on switch devices
1. MAC Layer Attacks Types
MAC address flooding 
Description :- Frames with unique, invalid source MAC addresses flood the switch, exhausting content addressable memory (CAM) table space, disallowing new entries from valid hosts. Traffic to valid hosts is subsequently flooded out all ports.
Mitigation Port security. MAC address VLAN access maps.
 
2. VLAN Attacks
i – VLAN hopping
By altering the VLAN ID on packets encapsulated for trunking, an attacking device can send or receive packets on various VLANs, bypassing Layer 3 security measures.
Mitigation  Tighten up trunk configurations and the negotiation state of unused ports. Place unused ports in a common VLAN.
 
ii – Attacks between devices on a common VLAN 
Devices might need protection from one another, even though they are on a common VLAN. This is especially true on service-provider segments that support devices from multiple customers.
Mitigation : – Implement private VLANs (PVLAN).
 
3. Spoofing Attacks
i – DHCP starvation and DHCP spoofing
An attacking device can exhaust the address space available to the DHCP servers for a period of time or establish itself as a DHCP server in man-in-themiddle attacks.
Mitigation :- Use DHCP snooping.
 
ii – Spanning-tree compromises 
Attacking device spoofs the root bridge in the STP topology. If successful, the network attacker can see a variety of frames.
Mitigation :- Proactively configure the primary and backup root devices. Enable root guard.
 
iii – MAC spoofing
Attacking device spoofs the MAC address of a valid host currently in the CAM table. The switch then forwards frames destined for the valid host to the attacking device.
Mitigation :- Use DHCP snooping, port security.
 
iv – Address Resolution Protocol (ARP) spoofing
Attacking device crafts ARP replies intended for valid hosts. The attacking device’s MAC address then becomes the destination address found in the Layer 2 frames sent by the valid network device.
Mitigation :- Use Dynamic ARP Inspection, DHCP snooping, port security.
 
4. Switch Device Attacks
i – Cisco Discovery Protocol (CDP) manipulation
Information sent through CDP is transmitted in clear text and unauthenticated, allowing it to be captured and divulge network topology information.
Mitigation :- Disable CDP on all ports where it is not intentionally used.
 
ii – Secure Shell Protocol (SSH) and Telnet attacks
Telnet packets can be read in clear text. SSH is an option but has security issues in version 1.
Mitigation : – Use SSH version 2. Use Telnet with vty ACLs.
Labels:

Comments

Post a Comment

Popular posts from this blog

How to import Putty Saved Connections to mRemoteNG

Just started using mRemoteNG and its being very cool to connect to different remote connection with different protocols e.g Window Remote Desktop, VNC to Linux, SSH, HTTP connection etc. from a single application. As new user I configured some remote desktop connection which was quite easy to figure out. But when I wanted to add SSH connections, it came in my mind to import all of the saved connections in the putty. But I couldn't figure it out how can it be done, though it was quite easy and here are the steps. Open your mRemoteNG Create a folder if you want segregation of multiple networks Create a new connection Enter the IP address of remote server under connection in Config pane Under the config pane, select protocol " SSH version 2 ".  Once you select protocol to SSH version 2 you are given option to import putty sessions, as shown in the snap below. In the above snap, I have imported CSR-AWS session from my saved sessions in Putty.
1 comment
Read more

BGP Local Preference Controlling Outbound Traffic in BGP

In BGP, Local Preference is used to control the outbound traffic path. It helps you decide which egress point (exit point) should be used when you have multiple connections to external networks, such as ISPs. Local Preference is an attribute that is local to your AS and is shared with all iBGP peers but not with eBGP neighbors. Higher Local Preference = More preferred outbound path. Example Scenario : You have two external links: ISP1 (via CE1) and ISP2 (via CE2). You want traffic to prefer ISP1 for all outbound traffic. Network Topology : CE1 (connected to ISP1): 10.0.1.1/30 CE2 (connected to ISP2): 10.0.2.1/30 iBGP Router (Internal) connected to both CE1 (10.0.1.2/30) and CE2 (10.0.2.2/30). Configuration on CE1 (Higher Local Preference) : Create a route map to set the local preference to 200 for routes learned from CE1: route-map SET_LOCAL_PREF permit 10 set local-preference 200 In the BGP configuration for CE1, apply this route map to the neighbor: router bgp 65001 ne...
Post a Comment
Read more

BGP MED: Managing Inbound Traffic with Multi-Exit Discriminator

The Multi-Exit Discriminator (MED) is used in BGP to control inbound traffic into your AS. It tells a neighboring AS which entry point into your network it should prefer when there are multiple links between your AS and the neighboring AS. The lower the MED value , the more preferred the path. MED is only honored between the same neighboring AS . Example Scenario : You are connected to ISP1 via two routers, CE1 and CE2 , and want to control which router ISP1 uses to send traffic into your AS. Network Topology : CE1 (connected to ISP1): 10.0.1.1/30 CE2 (connected to ISP1): 10.0.2.1/30 iBGP Router (Internal) connected to both CE1 (10.0.1.2/30) and CE2 (10.0.2.2/30). Configuration on CE1 (Lower MED, More Preferred) : Create a route map to set the MED to 50 for CE1: route-map SET_MED permit 10 set metric 50 Apply this route map to the neighbor in the BGP configuration for CE1: router bgp 65001 neighbor 10.0.1.1 remote-as 65000 neighbor 10.0.1.1 route-map SET_MED out Configuratio...
Post a Comment
Read more