rd6: A security assessment tool for attack vectors based on icmpv6 redirect messages

SYNOPSIS

rd6 [\|-i INTERFACE\|] [-s SRC_ADDR[/LEN]] [-d DST_ADDR] [-S LINK_SRC_ADDR] [-D LINK-DST-ADDR] [-A HOP_LIMIT] [-y FRAG_SIZE] [-u DST_OPT_HDR_SIZE] [-U DST_OPT_U_HDR_SIZE] [-H HBH_OPT_HDR_SIZE] [-r RD_DESTADDR/LEN] [-t RD_TARGETADDR/LEN] [-p PAYLOAD_TYPE] [-P PAYLOAD_SIZE] [-n] [-c HOP_LIMIT] [-x SRC_ADDR] [-a SRC_PORT] [-o DST_PORT] [-X TCP_FLAGS] [-q TCP_SEQ] [-Q TCP_ACK] [-V TCP_URP] [-w TCP_WIN] [-M] [-O] [-N] [-E LINK_ADDR] [-e] [-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] [-R N_DESTS] [-T N_TARGETS] [-F N_SOURCES] [-L | -l] [-z] [-v] [-h]

DESCRIPTION

rd6 allows the assessment of IPv6 implementations with respect to a variety of attack vectors based on ICMPv6 Redirect messages. This tool 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 passive. In active mode, the tool attacks a specific target, while in passive 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, a Redirect Destination Address, and a Redirect Target Address are specified. Passive 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 passive mode to respond incoming packets with ICMPv6 Redirect 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 Redirect 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 Redirect messages.

OPTIONS

rd6 takes it 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").

Depending on the amount of information (i.e., options) to be conveyed into the ICMPv6 Redirect messages, it may be necessary for the rd6 tool to split that information into more than one Redirect message. Also, if the tool is instructed to e.g. flood the victim with Redirect messages from different sources ("--flood-sources" option), multiple packets may need to be generated. rd6 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.

-iINTERFACE,--interfaceINTERFACE

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.

-sSRC_ADDR,--src-addressSRC_ADDR

This option specifies the IPv6 source address (or IPv6 prefix) to be used for the Source Address of the attack packets. This address typically corresponds to the IPv6 link-local address of the default router. If the "-F" ("--flood-sources") option is specified, this option includes an IPv6 prefix, from which random addresses are selected. See the description of the "-F" option for further information on how the "-s" option is processed in that specific case.

Note: Instead of specifying the "Source Address" with this option, the "--learn-router" option could be set, such that the tool automatically learns the IPv6 link-local address of the default router, and uses this address for the "Source Address" of the Redirect messages.

-dDST_ADDR,--dst-addressDST_ADDR

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

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

--hop-limit, -A

This option specifies the Hop Limit to be used for the Redirect messages. It defaults to 255. Note that IPv6 nodes are required to check that the Hop Limit of incoming Redirect messages is 255. Therefore, this option is only useful to assess whether an IPv6 implementation fails to enforce the aforementioned check.

-ySIZE,--frag-hdrSIZE

This option specifies that the resulting packet must be fragmented. The fragment size must be specified as an argument to this option.

-uHDR_SIZE,--dst-opt-hdrHDR_SIZE

This option specifies that a Destination Options header is to be included in the resulting packet. 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.

-UHDR_SIZE,--dst-opt-u-hdrHDR_SIZE

This option specifies a Destination Options header to be included in the "unfragmentable part" of the resulting packet. 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. This option is only valid if the "-y" option is specified (as the concept of "unfragmentable part" only makes sense when fragmentation is employed).

-HHDR_SIZE,--hbh-opt-hdrHDR_SIZE

This option specifies that a Hop-by-Hop Options header is to be included in the resulting packet. 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.

-SSRC_LINK_ADDR,--src-link-addressSRC_LINK_ADDR

This option specifies the link-layer Source Address of the Redirect messages (this option is only valid for Ethernet interfaces). If left unspecified, the link-layer Source Address is randomized. However, if this option is left unspecified, but the "--learn-router" option is set, the link-layer Source Address is set to that of the default router for the local network.

-DDST_LINK_ADDR,--dst-link-addressDST_LINK_ADDR

This option specifies the link-layer Destination Address of the Redirect messages (this option is only valid for Ethernet interfaces). If left unspecified, it is set to the "all-nodes link-local multicast" address (ff02::1).

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

--redir-target, -t

This option specifies the Target Address of the Redirect messages. If the "-T" ("--flood-targets") option is specified, this option specifies an IPv6 prefix in the form "-t prefix/prefixlen". See the description of the "-T" option for further information on how the "-t" option is processed in that specific case.

This option can be left unspecified only if the "--make-onlink" option is selected, in which case the Redirect Target Address is set to the same value as the Redirect Destination address.

--redir-dest, -r

This option specifies the Redirect Destination Address. If the "-R" ("--flood-dests") option is specified, this option specifies an IPv6 prefix in the form "-r prefix/prefixlen". See the description of the "-R" option for further information on how the "-t" option is processed in that specific case.

--payload-type, -p

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

--payload-size, -P

Size of the payload to be included in the Redirect message (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).

--no-payload, -n

This option specifies that no payload (i-e-, no Redirected Header option) should be included in the Redirect message.

--ipv6-hlim, -c

This option specifies the Hop Limit of the IPv6 packet included in the payload of the Redirect message. It defaults to 255.

--peer-addr, -x

This option specifies the IPv6 Source Address of the Redirect payload. If left unspecified, the IPv6 Source Address of the Redirect payload is set to the same value as the IPv6 Destination Address of the packet. This option is only employed for packets sent in "active" mode.

Note: this option might be useful to check whether an implementation validates the contents of the Redirect message.

--redir-port, -o

This option specifies the Destination Port of the TCP or UDP packet contained in the Redirect payload.

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

--peer-port, -a

This option specifies the Source Port of the TCP or UDP packet contained in the Redirect payload.

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

--tcp-flags, -X

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