NAME

icmp6 - A security assessment tool for attack vectors based on ICMPv6 packets

SYNOPSIS

icmp6 [-i INTERFACE] [-s SRC_ADDR[/LEN]] [-d DST_ADDR] [-S LINK_SRC_ADDR] [-D LINK-DST-ADDR] [-c HOP_LIMIT] [-y FRAG_SIZE] [-u DST_OPT_HDR_SIZE] [-U DST_OPT_U_HDR_SIZE] [-H HBH_OPT_HDR_SIZE] [-t TYPE[:CODE] | -e CODE | -A CODE -V CODE -R CODE] [-r TARGET_ADDR] [-x PEER_ADDR] [-c HOP_LIMIT] [-m MTU] [-O POINTER] [-p PAYLOAD_TYPE] [-P PAYLOAD_SIZE] [-n] [-a SRC_PORTL[:SRC_PORTH]] [-o DST_PORTL[:DST_PORTH]] [-X TCP_FLAGS] [-q TCP_SEQ] [-Q TCP_ACK] [-V TCP_URP] [-w TCP_WIN] [-M] [-j PREFIX[/LEN]] [-k PREFIX[/LEN]] [-J LINK_ADDR] [-K LINK_ADDR] [-b PREFIX[/LEN]] [-g PREFIX[/LEN]] [-B LINK_ADDR] [-G LINK_ADDR] [-f] [-L | -l] [-z] [-v] [-h]

DESCRIPTION

icmp6 allows the assessment of IPv6 implementations with respect to a variety of attack vectors based on ICMPv6 error messages. It is part of the SI6 Networks' IPv6 Toolkit: a security assessment suite for the IPv6 Protocols.

This tool has two modes of operation: "active" and "listening". In active mode, the tool attacks a specific target without listening to any incoming traffic, while in "listening" mode the tool listens to traffic on the local network, and launches an attack in response to such traffic. Active mode is employed if an IPv6 Destination Address is specified. "Listening" mode is employed if the "-L" option (or its long counterpart "--listen") is set. If both an attack target and the "-L" option are specified, the attack is launched against the specified target, and then the tool enters "listening" mode to respond incoming packets with ICMPv6 error messages.

The tool supports filtering of incoming packets based on the Ethernet Source Address, the Ethernet Destination Address, the IPv6 Source Address, and the IPv6 Destination Address. There are two types of filters: "block filters" and "accept filters". If any "block filter" is specified, and the incoming packet matches any of those filters, the message is discarded (and thus no ICMPv6 error messages are sent in response). If any "accept filter" is specified, incoming packets must match the specified filters in order for the tool to respond with ICMPv6 error messages.

OPTIONS

icmp6 takes its parameters as command-line options. Each of the options can be specified with a short name (one character preceded with the hyphen character, as e.g. "-i") or with a long name (a string preceded with two hyphen characters, as e.g. "--interface").

The icmp6 tool supports IPv6 fragmentation, which might be of use to circumvent layer-2 filtering and/or Network Intrusion Detection Systems (NIDS). However, IPv6 fragmentation is not enabled by default, and must be explicitly enabled with the "-y" option.

-i INTERFACE, --interface INTERFACE

This option specifies the network interface that the tool will use. If the destination address ("-d" option) is a link-local address, or the "listening" ("-L") mode is selected, the interface must be explicitly specified. The interface may also be specified along with a destination address, with the "-d" option.

-s SRC_ADDR, --src-address SRC_ADDR

This option specifies the IPv6 source address (or IPv6 prefix) to be used for the Source Address of the attack packets. If a prefix is specified, the Source Address is randomly selected from that prefix. If this option is left unspecified, the IPv6 Source Address of the attack packets is randomly selected from the prefix ::/0.

-d DST_ADDR, --dst-address DST_ADDR

This option specifies the IPv6 Destination Address of the victim. It can be left unspecified only if the "-L" option is selected (that is, if the tool is to operate in "listening" mode).

When operating in "listening" mode ("-L" option), the IPv6 Destination Address is selected according to the IPv6 Source Address of the incoming packet.

-S SRC_LINK_ADDR, --src-link-address SRC_LINK_ADDR

This option specifies the link-layer Source Address of the attack packets. If left unspecified, the link-layer Source Address is randomized.

-D DST_LINK_ADDR, --dst-link-address DST_LINK_ADDR

This option specifies the link-layer Destination Address of the attack packets. If left unspecified, it is set to that of the local router (for non-local destinations) or to that corresponding to the destination host (for local hosts).

When operating in "listening" mode, the link-layer Destination Address is set to the link-layer Source Address of the incoming packet.

-c HOP_LIMIT, --hop-limit HOP_LIMIT

This option specifies the Hop Limit to be used for the Redirect messages. If this option is left unspecified, the Hop Limit is randomized to a value between 64 and 243.

-y SIZE, --frag-hdr SIZE

This option specifies that the ICMPv6 error messages must be fragmented. The fragment size must be specified as an argument to this option.

-u HDR_SIZE, --dst-opt-hdr HDR_SIZE

This option specifies that a Destination Options header is to be included in the outgoing packet(s). The extension header size must be specified as an argument to this option (the header is filled with padding options). Multiple Destination Options headers may be specified by means of multiple "-u" options.

-U HDR_SIZE, --dst-opt-u-hdr HDR_SIZE

This option specifies a Destination Options header to be included in the "unfragmentable part" of the outgoing packet(s). The header size must be specified as an argument to this option (the header is filled with padding options). Multiple Destination Options headers may be specified by means of multiple "-U" options.

-H HDR_SIZE, --hbh-opt-hdr HDR_SIZE

This option specifies that a Hop-by-Hop Options header is to be included in the outgoing packet(s). The header size must be specified as an argument to this option (the header is filled with padding options). Multiple Hop-by-Hop Options headers may be specified by means of multiple "-H" options.

-t TYPE, --icmp6 TYPE

This option specifies the Type and Code of the ICMPv6 error message in the form "--icmp6 TYPE:CODE". If left unspecified, the ICMPv6 error message defaults to "Parameter Problem, Erroneous header field encountered" (Type 4, Code 0).

Note: Other options (such as "--icmp6-unreachable") provide an alternative for setting the ICMPv6 Type and Code.

-e, --icmp6-dest-unreach

This option sets the ICMPv6 Type to "1" (Destination Unreachable), and allows the user to specify the ICMPv6 Code, in the form "--icmp6-dest-unreach CODE".

Note: this option is an alternative to the "-t" option for setting the ICMPv6 Type and Code.

-E, --icmp6-packet-too-big

This option sets the ICMPv6 Type to "1", and the ICMPv6 Code to "0" (Packet Too Big).

Note: this option is an alternative to the "-t" option for setting the ICMPv6 Type and Code.

-A, --icmp6-time-exceeded

This option sets the ICMPv6 Type to "3" (Time Exceeded), and allows the user to specify the ICMPv6 Code, in the form "--icmp6-time-exceeded CODE".

Note: this option is an alternative to the "-t" option for setting the ICMPv6 Type and Code.

-R, --icmp6-param-problem

This option sets the ICMPv6 Type to "4" (Parameter Problem), and allows the user to specify the ICMPv6 Code, in the form "--icmp6-param-problem CODE".

Note: this option is an alternative to the "-t" option for setting the ICMPv6 Type and Code.

-m MTU, --mtu MTU

This specifies the value of the "MTU" field of ICMPv6 Packet Too Big error messages.

-O POINTER, --pointer POINTER

This option specifies the value of the "Pointer" field of ICMPv6 Parameter Problem error messages.

-p TYPE, --payload-type TYPE

This option specifies the payload type to be included in the ICMPv6 Payload. Currently supported payloads are "TCP", "UDP", and "ICMP6". The payload-type defaults to "TCP".

When the tool operates in "Listening" mode, this option specifies the type of packets the tool will listen to. In listening mode, an additional type can be specified: "IP6"; this will cause the tool to listen to all IPv6 traffic.

-P SIZE, --payload-size SIZE

Size of the payload to be included in the ICMPv6 Payload (with the payload type being specified by the "-p" option). By default, as many bytes as possible are included, without exceeding the minimum IPv6 MTU (1280 bytes).

-n, --no-payload

This option specifies that no payload should be included within the ICMPv6 error message.

-C HOP_LIMIT, --ipv6-hlim HOP_LIMIT

This option specifies the Hop Limit of the IPv6 packet included in the payload of the ICMPv6 error message. If this option is left unspecified, the Hop Limit is randomized to a value between 64 and 243.

-r ADDRESS, --target-addr ADDRESS

This option specifies the Source Address of the IPv6 packet that is embedded in the ICMPv6 error message. If left unspecified, it is set to the same address as the IPv6 Destination Address of the outer packet.

When operating in "Listening mode", the tool automatically embeds a piece of the received packet (unless otherwise specified by the "-n" option), and hence the IPv6 Source Address of the embedded IPv6 packet is set accordingly.

-x ADDRESS, --peer-addr ADDRESS

This option specifies the Destination Address of the IPv6 packet that is embedded in the ICMPv6 error message. If left unspecified, it is set to a random value.

When operating in "Listening mode", the tool automatically embeds a piece of the received packet (unless otherwise specified by the "-n" option), and hence the IPv6 Destination Address of the embedded IPv6 packet is set accordingly.

Note: since the victim host is expected to check that the ICMPv6 error message corresponds to an ongoing communication instance, when operating in "active mode", this option should be set to a value that corresponds to an ongoing communication instance.

-o PORT, --target-port PORT

This option specifies the Source Port of the TCP or UDP packet contained in the ICMPv6 Payload. If a port range is specified in the form "-o LOWPORT:HIGHPORT" the tool will send one ICMPv6 error message for each port in that range.

Note: This option is meaningful only if "TCP" or "UDP" have been specified (with the "-p" option).

-a PORT, --peer-port PORT

This option specifies the Destination Port of the TCP or UDP packet contained in the ICMPv6 Payload. If a port range is specified in the form "-o LOWPORT:HIGHPORT" the tool will send one ICMPv6 error message for each port in that range.

Note: This option is meaningful only if "TCP" or "UDP" have been specified (with the "-p" option).

-X TCP_FLAGS, --tcp-flags TCP_FLAGS

This option specifies the flags of the TCP header contained in the ICMPv6 Payload. The flags are specified as "F" (FIN), "S" (SYN), "R" (RST), "P" (PSH), "A" (ACK), "U" (URG), "X" (no flags). If left unspecified, only the "ACK" bit is set.