Fix methods relating to answer/question data structures which were
set up for Net::DNS objects in the original implementation
utilizing uppercase letters in the exact same method names.
Testing:
None yet, completely forgot i even wrote this module till i saw
it in my merge conflicts after upstream merged the PR.
DNS spoofing module should be feature complete, with forwarding of
requests which do not have cached answers (can be disabled same as
the native server module), empty replies to reduce client wait on
outstanding DNS requests, and post-send output in verbose mode
to reduce garbage and execution time in the critical/racy path.
This module is best used in conditions where MITM is achieved by
way of MAC spoofing, route interception, or compromise of an inline
host on the datapath. The attacker should avoid forwarding
original requests to the intended destination, or if this is not
possible, prevent replies from traversing the MITM space in order
to avoid race conditions between the spoofer and victim.
Example iptables configuration on MITM host:
iptables -t nat -A POSTROUTING -o eth0 -p udp ! --dport 53 -j ...
Testing:
Internal testing in Virtualbox local network, atop 802.11, and
mostly in Neutron (with port security disabled on the VIFs) atop
OpenStack Liberty ML2+OVS.
Move all output lines out of the execution path in order to reduce
execution time and help win the race against the real response.
Update the IP header ID for responses so as not to return the sent
header value on the wire and alert clever IDS.
Allow retrieval of '*' from stored static entries for spoofing
all domains to any IP using wildcard names. Replace the wildcard
response with the name submitted to the search in the response.
Fix improper checks in DNS::Packet for Resolv objects from decode
to encode.
Misc cleanup for records not responding to :address, convenience
methods, and packet structure.
Import PCAP-based DNS spoofing server module:
This module uses the Capture mixin to sniff and parse packets off
the wire, then match answers to sniffed requests from static
entries in the server's cache. If answers are found, they are
appended to a cloned packet with reverse saddr/daddr pairs at
layers 2-4, the qr bit is set, and it is injected back into the
interface from where it came.
Minor cleanup in the Rex::Proto::DNS::Server::Cache class to allow
multiple address->name pairs and fix issues when adding multiple
static entries.
See the complaint on #4039. This doesn't fix that particular
issue (it's somewhat unrelated), but does solve around
a file parsing problem reported by @void-in
William Vu