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arpon

NAME

arpon - Arp handler inspectiON

SYNOPSIS

arpon [ -ndfgiolmpbraetuszycvh ]

       [ -n Nice value ]

       [ -f Log file ]

       [ -i Device ]

       [ -m Timeout ] [ -p Inet4 ]

       [ -a Inet4 MAC ] [ -e Inet4 or MAC ]

       [ -u timeout ] [ -z timeout ]

        

DESCRIPTION

ArpON (Arp handler inspectiON) is a portable handler daemon with some nice tools to handle all ARP aspects. It has a lot of features and it makes Arp a bit safer. This is possible using two kinds of anti Arp Poisoning tecniques, the first is based on SARPI or "Static Arp Inspection", the second on DARPI or "Dynamic Arp Inspection" approach. Keep in mind other common tools fighting ARP poisoning usually limit their activity only to point out the problem instead of blocking it, ArpON does it using SARPI and DARPI policies. Finally you can use ArpON to pentest some switched/hubbed LAN with/without DHCP protocol, in fact you can disable the daemon in order to use the tools to poison the ARP Cache. However ArpON is also a good tool to a clever sysadmin aware of security related topics. It is a tool born to make Arp secure in order to avoid Arp Spoofing/Poisoning & co.

Remember it doesn't affect the communication efficiency of the ARP protocol!

OPTIONS

TASK MODE

-n (--nice) <"Nice Value">

Sets PID's CPU priority (Default: 0 nice) for Realtime work for many CPU architectures (little/big endian with 32/64 bits).

-d (--daemon)

Works in background task (Default: /var/run/arpon.pid).

LOG MODE

-f (--log-file) <"Log file">

Sets log file (Default: /var/log/arpon.log).

-g (--log)

Works in logging mode.

DEVICE MANAGER

ArpON is an ARP handler and it is able to handle network devices automatically or manually, to print a list of up network interfaces of the system (it uses the last of the list). It identifies the interface's datalink layer you are using but it supports only Ethernet/Wireless as datalink. ArpON sets the netowrk interface and it deletes the PROMISCUE flag.

-i (--dev-manual) <"Device">

Sets your Ethernet device manually.

-o (--dev-auto)

Sets Ethernet device automatically.

-l (--dev-list)

Prints all Ethernet devices.

ARP PING

Among all its features ArpON is able to ping using ARP a host, the possibility to ping the broadcast address (it can compute the number of up host through netmask address, it recognizes the address class INET/IPV4), then it prints a up host's list of the LAN. Timeout is set by default to 500 ms, but you can override this value.

-m (--ping-timeout) <"Timeout">

 Sets Arp Ping response timeout (Default: 500 ms).

-p (--ping-host) <"Inet4">

Sends Arp Ping to Inet4 address.

-b (--ping-broadcast)

Sends Arp Ping to Broadcast address (Builds and prints LAN's active hosts).

ARP PASSIVE SNIFFER

ArpON can be also a passive sniffer and so it can capture all inbound/outbound ARP packets, requests and replies, in TcpDump style.

-r (--sniff-arp)

Sniffs only Arp protocol (I/O Arp Request/Reply).

ARP CACHE MANAGER

ArpON is not over, in fact it can handle system's ARP cache, it has the possibility to add, delete the entries and to print the current cache.

-a (--cache-add) <"Inet4 MAC">

Adds Inet4 and MAC Arp entry.

-e (--cache-del) <"Inet4 | MAC">

Deletes Inet4 or MAC Arp entry.

-t (--cache-list)

Prints total ARP Cache entries.

STATIC ARP INSPECTION

When SARPI starts, it saves statically all the ARP entries it finds in the ARP cache in a static cache called SARPI Cache. Note that you can also manage the ARP cache before starting SARPI, through the "ARP CACHE MANAGER" feature of ArpON. After the startup, ArpON operations are split in two parallel tasks:

- It automatically updates the ARP cache each time the timeout expires; timeout is simply the expire time of each entry in the ARP cache, defined according to the policy set in the running kernel. Timeout is set by default to 10 minutes, but you can override this value.

- It applies policies to the ARP cache, according to the following three schemes:

1) For each received ARP reply, ArpON checks whether source addresses match an entry in the SARPI cache. In such case, the new entry will overwrite the old one, previously saved in the static cache.

2) For each received ARP request, ArpON checks wheter the source addresses match an entry in the SARPI cache. In such case, the new entry will overwrite the old one, previously saved in the static cache.

3) Every ARP request/reply whose source address doesn't match an entry in the SARPI cache are just ignored.

Both these operations are a countermeasure against ARP Poisoning/Spoofing attacks, as SARPI detects and blocks them. SARPI doesn't affect the communication efficiency of the ARP protocol. SARPI just manages a list with static entries, making it an optimal choice in those networks without DHCP. Finally, it's possible to use SARPI as a daemon, using the "TASK MODE" feature of ArpON.

-u (--sarpi-timeout) <"Timeout">

Sets Arp Cache refresh timeout (Default: 10 minuts).

-s (--sarpi)

Manages Arp Cache statically.

DYNAMIC ARP INSPECTION

DARPI startup phase consists in cleaning up the ARP cache, deleting all of its entries. This is due because ARP cache may have poisoned entries from the beginning. DARPI handles the so called DARPI cache, applying different policies to different kinds of packets:

- ARP request: It traces ARP requests and follows these rules if traffic is:

1) Outbound: Packets are generated by us. ArpON let them pass, adding an entry with the target to the DARPI cache (see ARP reply - Inbound). On this DARPI cache entry, DARPI sets timeout because if this entry doesn't exist in network, DARPI must to delete it.

2) Inbound: Packets come to us from the network. ArpON refuses the packet, deleting the entry of the source address from the ARP cache, because such packet may be poisoned. Afterwards, the kernel will send an ARP request to the source address, and it will be managed by ArpON through DARPI. Here, ArpON will defend and block ARP Poisoning/Spoofing attacks through the ARP requests.

- ARP reply: It traces the ARP replies, and follows these rules if traffic is:

1) Outbound: Packets are generated by us. ArpON just lets them pass.

2) Inbound: Packets come to us from the network. ArpON checks whether the source address matches an entry in the DARPI cache (see ARP request - Outbound), it lets the packet flow, adding an entry in the ARP cache. Otherwise, if the source address doesn't match any entry in the DARPI cache, ArpON refuses the packet, deleting the entry from the ARP cache. Here ArpON defends and blocks ARP Poisoning/Spoofing attacks through the ARP replies.

Both types of packets are used to perform ARP Poisoning/Spoofing attacks, as DARPI detects and blocks them. DARPI doesn't affect the communication efficiency of the ARP protocol. DARPI manages uniquely a list with dynamic entries. Therefore it's an optimal solution in networks having DHCP. Finally, it's possible to use DARPI as a network daemon, through the feature "TASK MODE" of ArpON.

-z (--darpi-timeout)

Sets DARPI Cache entry timeout (Default: 500 milliseconds).

-y (--darpi)

Manages Arp Cache dinamically.

MISC

-c (--license)

Prints license page.

-v (--version)

Prints version number.

-h (--help)

Prints help summary page.

EXAMPLES

- Print the interfaces list:

 # arpon -l
 
   [09/05/2008 - 18:20:23 CEST] Device: (eth0) MAC: 0:e0:4c:xx:xx:xx Inet4: 192.168.1.7 Netmask: 255.255.255.0
   [09/05/2008 - 18:20:23 CEST] Device: (eth1) MAC: aa:0:4:xx:xx:xx Inet4: 192.168.1.3 Netmask: 255.255.255.0
 
 
 

- Print ethernet datalink:

 # arpon -i eth0
 
   [09/05/2008 - 18:21:06 CEST] Device: (eth0) MAC: 0:e0:4c:xx:xx:xx Inet4: 192.168.1.7 Netmask: 255.255.255.0
 
 
 

- Print automatic network interfaces:

 # arpon -o
 
   [09/05/2008 - 18:22:25 CEST] Device: (eth1) MAC: aa:0:4:xx:xx:xx Inet4: 192.168.1.3 Netmask: 255.255.255.0
 
 
 

- Arp ping to host with 10 milliseconds timeout:

 # arpon -m 10 -p 192.168.1.1
 
   [09/05/2008 - 18:25:08 CEST] Device: (eth1) MAC: aa:0:4:xx:xx:xx Inet4: 192.168.1.3 Netmask: 255.255.255.0
   [09/05/2008 - 18:25:08 CEST] Arp Ping to Host (192.168.1.1) with timeout: 10 milliseconds.
   [09/05/2008 - 18:25:08 CEST] -> Arp who-has 192.168.1.1 (ff:ff:ff:ff:ff:ff) tell 192.168.1.3 (aa:0:4:xx:xx:xx)
   [09/05/2008 - 18:25:08 CEST] <- Arp reply 192.168.1.1 is-at (0:17:37:xx:xx:xx)
 
 
 

- Arp ping to broadcast with -20 nice, logging mode and 20 milliseconds timeout:

 # arpon -n -20 -g -m 20 -b
 
   [09/05/2008 - 18:26:43 CEST] Device: (eth1) MAC: aa:0:4:xx:xx:xx Inet4: 192.168.1.3 Netmask: 255.255.255.0
   [09/05/2008 - 18:26:43 CEST] Arp Ping to Broadcast with timeout: 20 milliseconds, Class: "C", Possible Hosts: 255.
   [09/05/2008 - 18:26:43 CEST] 1) Inet4:     192.168.1.1  ->  Mac:  0:17:37:xx:xx:xx
   [09/05/2008 - 18:26:43 CEST] 2) Inet4:     192.168.1.2  ->  Mac:  0:12:dc:xx:xx:xx
   [09/05/2008 - 18:26:43 CEST] 3) Inet4:     192.168.1.4  ->  Mac:    0:4f:4e:xx:xx:xx
   [09/05/2008 - 18:26:43 CEST] 4) Inet4:     192.168.1.5  ->  Mac:   0:e0:4c:xx:xx:xx
 
 
 

- Arp passive sniffer with logging mode:

 # arpon -f ./arpon.log -g -i eth1 -r
 
   [09/05/2008 - 18:28:35 CEST] Device: (eth1) MAC: aa:0:4:xx:xx:xx Inet4: 192.168.1.3 Netmask: 255.255.255.0
   [09/05/2008 - 18:28:35 CEST] Sniffing Arp packets:
   [09/05/2008 - 18:28:57 CEST] <- Arp who-has 192.168.1.1 (ff:ff:ff:ff:ff:ff) tell 192.168.1.3 (aa:0:4:xx:xx:xx)
   [09/05/2008 - 18:28:57 CEST] -> Arp reply 192.168.1.1 is-at (0:17:37:xx:xx:xx)
   [09/05/2008 - 18:30:22 CEST] <- Arp who-has 192.168.1.5 (ff:ff:ff:ff:ff:ff) tell 192.168.1.3 (aa:0:4:xx:xx:xx)
   [09/05/2008 - 18:30:22 CEST] -> Arp reply 192.168.1.5 is-at (0:e0:4c:xx:xx:xx)
   [09/05/2008 - 18:29:01 CEST] Arp packets stats:
   [09/05/2008 - 18:29:01 CEST] Received "Arp Total": 2
   [09/05/2008 - 18:29:01 CEST] Received "Arp Request": 1
   [09/05/2008 - 18:29:01 CEST] Received "Arp Reply": 1
 
 
 

- Manage ARP cache

 The arp cache management includes this operation:
   1) Get the current arp cache list
   2) Add entry 192.168.1.10 aa:bb:cc:dd:ee:ff
   3) Get updated arp cache list
   4) Elimination of the last entry
   5) Get updated arp cache list
 
 This operation can be execute in a single command:
 
 # arpon -t -a "192.168.1.10 aa:bb:cc:dd:ee:ff" -t -e aa:bb:cc:dd:ee:ff -t
 
   [09/05/2008 - 18:31:34 CEST] Arp Cache list:
   [09/05/2008 - 18:31:34 CEST] 1)     192.168.1.5 ->   0:e0:4c:xx:xx:xx
   [09/05/2008 - 18:31:34 CEST] 2)     192.168.1.2 ->  0:12:dc:xx:xx:xx
   [09/05/2008 - 18:31:34 CEST] 3)     192.168.1.4 ->    0:4f:4e:xx:xx:xx
   [09/05/2008 - 18:31:34 CEST] 4)     192.168.1.1 ->  0:17:37:xx:xx:xx
   
   [09/05/2008 - 18:31:34 CEST] Arp Cache added 192.168.1.10 -> aa:bb:cc:dd:ee:ff entry.
   
   [09/05/2008 - 18:31:34 CEST] Arp Cache list:
   [09/05/2008 - 18:31:34 CEST] 1)     192.168.1.5 ->   0:e0:4c:xx:xx:xx
   [09/05/2008 - 18:31:34 CEST] 2)    192.168.1.10 -> aa:bb:cc:dd:ee:ff
   [09/05/2008 - 18:31:34 CEST] 3)     192.168.1.2 ->  0:12:dc:xx:xx:xx
   [09/05/2008 - 18:31:34 CEST] 4)     192.168.1.4 ->    0:4f:4e:xx:xx:xx
   [09/05/2008 - 18:31:34 CEST] 5)     192.168.1.1 ->  0:17:37:xx:xx:xx
   
   [09/05/2008 - 18:31:34 CEST] Arp Cache deleted 192.168.1.10 -> aa:bb:cc:dd:ee:ff entry.
   
   [09/05/2008 - 18:31:34 CEST] Arp Cache list:
   [09/05/2008 - 18:31:34 CEST] 1)     192.168.1.5 ->   0:e0:4c:xx:xx:xx
   [09/05/2008 - 18:31:34 CEST] 2)     192.168.1.2 ->  0:12:dc:xx:xx:xx
   [09/05/2008 - 18:31:34 CEST] 3)     192.168.1.4 ->    0:4f:4e:xx:xx:xx
   [09/05/2008 - 18:31:34 CEST] 4)     192.168.1.1 ->  0:17:37:xx:xx:xx
 
 
 

- Static ARP Inspection:

 With -10 nice, logging mode, 1 minut of timeout for arp cache refresh:
 
 # arpon -n -10 -g -o -u 1 -s 
 
   [09/05/2008 - 18:33:40 CEST] Device: (eth1) MAC: aa:0:4:xx:xx:xx Inet4: 192.168.1.3 Netmask: 255.255.255.0
   [09/05/2008 - 18:33:40 CEST] SARPI Start...
   [09/05/2008 - 18:33:40 CEST] SARPI protects these Arp Cache's entries:
   [09/05/2008 - 18:33:40 CEST] 1)     192.168.1.2 ->  0:12:dc:xx:xx:xx
   [09/05/2008 - 18:33:40 CEST] 2)     192.168.1.4 ->    0:4f:4e:xx:xx:xx
   [09/05/2008 - 18:33:40 CEST] 3)     192.168.1.1 ->  0:17:37:xx:xx:xx
   [09/05/2008 - 18:33:40 CEST] SARPI Arp Cache refresh timeout: 1 minut.
   [09/05/2008 - 18:33:40 CEST] SARPI Realtime Protect actived!
   [09/05/2008 - 18:33:58 CEST] SARPI Arp Request Inbound: Refresh 192.168.1.1 -> 0:17:37:xx:xx:xx entry in Arp Cache.
   [09/05/2008 - 18:33:58 CEST] SARPI Arp Reply Outbound: Send to 192.168.1.1 -> 0:17:37:xx:xx:xx
   [09/05/2008 - 18:38:09 CEST] SARPI Arp Request Outbound: Send to 192.168.1.5 -> ff:ff:ff:ff:ff:ff
   [09/05/2008 - 18:38:09 CEST] SARPI Arp Reply Inbound: Ignores entry in Arp Cache: 192.168.1.5 -> 0:e0:4c:xx:xx:xx
 
 
 

- Dynamic ARP Inspection:

 With 0 nice (default), logging mode:
 
 # arpon -g -y
 
   [09/05/2008 - 18:35:35 CEST] Device: (eth1) MAC: aa:0:4:xx:xx:xx Inet4: 192.168.1.3 Netmask: 255.255.255.0
   [09/05/2008 - 18:35:35 CEST] DARPI Start...
   [09/05/2008 - 18:35:35 CEST] DARPI deletes these Arp Cache entries:
   [09/05/2008 - 18:35:35 CEST] 1)     192.168.1.5 ->   0:e0:4c:xx:xx:xx
   [09/05/2008 - 18:35:35 CEST] 2)     192.168.1.2 ->  0:12:dc:xx:xx:xx
   [09/05/2008 - 18:35:35 CEST] 3)     192.168.1.4 ->    0:4f:4e:xx:xx:xx
   [09/05/2008 - 18:35:35 CEST] 4)     192.168.1.1 ->  0:17:37:xx:xx:xx
   [09/05/2008 - 18:35:35 CEST] DARPI Cache entry timeout: 500 milliseconds.
   [09/05/2008 - 18:35:35 CEST] DARPI Realtime Protect actived!
   [09/05/2008 - 18:35:45 CEST] DARPI Arp Request Outbound: Added 192.168.1.1 entry in DARPI Cache!
   [09/05/2008 - 18:35:45 CEST] DARPI Arp Reply Inbound: 192.168.1.1 entry found in DARPI Cache, deleted it.
   [09/05/2008 - 18:35:45 CEST] DARPI added 192.168.1.1 -> 0:17:37:xx:xx:xx entry in Arp Cache.
   [09/05/2008 - 18:36:23 CEST] DARPI Arp Request Inbound: deleted 192.168.1.1 -> 0:17:37:xx:xx:xx entry from Arp Cache.
   [09/05/2008 - 18:36:23 CEST] DARPI Arp Reply Outbound: Send to 192.168.1.1 -> 0:17:37:xx:xx:xx
   [09/05/2008 - 18:36:23 CEST] DARPI Arp Request Outbound: Added 192.168.1.1 entry in DARPI Cache!
   [09/05/2008 - 18:36:23 CEST] DARPI Arp Reply Inbound: 192.168.1.1 entry found in DARPI Cache, deleted it.
   [09/05/2008 - 18:36:23 CEST] DARPI added 192.168.1.1 -> 0:17:37:xx:xx:xx entry in Arp Cache.
 
 
 

- Multiplexing Interfaces:

 With 0 nice (default), daemon mode, 2 interfaces, en0 with Dynamic
 Arp Inspection, en1 with Static Arp Inspection and 2 logging files: 
 
 # arpon -d -f darpi.log -g -i eth0 -z 100 -y -f sarpi.log -g -i eth1 -u 10 -s
 
   [09/05/2008 - 18:42:13 CEST] Task is forking to background, using /var/run/arpon.pid pid file...
 
  In this example, when you want to read network traffic, you can to use:
    - eth0: ./darpi.log
    - eth1: ./sarpi.log
 
 
 

AUTHORS

ArpON was writen by: Andrea Di Pasquale aka "spikey" <spikey.it@gmail.com>

The current version is available via http:

                 http://arpon.sourceforge.net
 
 

Special Thanks to:

 
 Mariano Graziano aka "emdel" <emdel@playhack.net>
         Web master, he proposed SARPI idea, thank you!
 
 Andrea Barberio aka "insomniac" <insomniac@slackware.it>
         Beta tester, LD_PRELOAD idea, thank you!
 
 Marco Fabre aka "Morpe" <twatac@gmail.com>
         ArpON's logo!
 
 Giuseppe Marco Randazzo aka "zeld" <zeld@freaknet.org>
         Man page.
 
 Giuseppe Iuculano aka "Derevko" <giuseppe@iuculano.it>
       Adjusted man page, added pid file, thank you!
 
 Allan Jigpe Eversun aka "jigp" <allan@digitaldev.com>
         Tester, thank you! 
 
 
 

BUGS

Please send problems, bugs, questions, desirable enhancements, patch, source code contributions, etc. to:

spikey.it@gmail.com