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extend and refact script-side of NTP analyzer

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Palumbo Mauro 2019-06-03 17:50:32 +02:00
parent 411908a102
commit ce07b10aa8
3 changed files with 180 additions and 105 deletions
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3
scripts/base/protocols/ntp/__load__.zeek
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# Generated by binpac_quickstart
@load ./main @load ./main
@load ./consts #@load-sigs ./dpd.sig

14
scripts/base/protocols/ntp/dpd.sig
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# Generated by binpac_quickstart
signature dpd_ntp { signature dpd_ntp {
ip-proto == udp
# ## TODO: Define the payload. When Bro sees this regex, on ip-proto == udp
# ## TODO: Define the payload. When Bro sees this regex, on
# ## any port, it will enable your analyzer on that # ## any port, it will enable your analyzer on that
# ## connection. # ## connection.
# ## payload /^NTP/ # ## payload /^NTP/
enable "ntp" enable "ntp"
} }

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scripts/base/protocols/ntp/main.zeek
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module NTP; module NTP;
@load ./consts # TODO: The recommended method to do dynamic protocol detection
# (DPD) is with the signatures in dpd.sig.
# For the time being, we use port detection.
const ports = { 123/udp };
redef likely_server_ports += { ports };
export { export {
redef enum Log::ID += { LOG }; redef enum Log::ID += { LOG };
type Info: record { type Info: record {
## Timestamp for when the event happened. ## Timestamp for when the event happened.
ts: time &log; ts: time &log;
## Unique ID for the connection. ## Unique ID for the connection.
uid: string &log; uid: string &log;
## The connection's 4-tuple of endpoint addresses/ports. ## The connection's 4-tuple of endpoint addresses/ports.
id: conn_id &log; id: conn_id &log;
## The version of NTP ## The NTP version number (1, 2, 3, 4)
ver: count &log; version: count &log;
## The stratum (primary, secondary, etc.) of the server ## The NTP mode being used
stratum: count &log &optional; mode: count &log;
## The precision of the system clock of the client ## The stratum (primary server, secondary server, etc.)
precision: interval &log &optional; stratum: count &log;
## The time at the client that the request was sent to the server ## The maximum interval between successive messages
org_time: time &log &optional; poll: interval &log;
## The time at the server when the request was received ## The precision of the system clock
rec_time: time &log &optional; precision: interval &log;
## The time at the server when the reply was sent ## Total round-trip delay to the reference clock
xmt_time: time &log &optional; root_delay: interval &log;
## For stratum 0, 4 character string used for debugging ## Total dispersion to the reference clock
kiss_code: string &log &optional; root_disp: interval &log;
## For stratum 1, ID assigned to the clock by IANA ## For stratum 0, 4 character string used for debugging
ref_id: string &log &optional; kiss_code: string &optional &log;
## The IP of the server's reference clock ## For stratum 1, ID assigned to the reference clock by IANA
ref_clock: addr &log &optional; ref_id: string &optional &log;
## Above stratum 1, when using IPv4, the IP address of the reference clock
ref_addr: addr &optional &log;
## Above stratum 1, when using IPv6, the first four bytes of the MD5 hash of the
## IPv6 address of the reference clock
ref_v6_hash_prefix: string &optional &log;
## Time when the system clock was last set or correct
ref_time: time &log;
## Time at the client when the request departed for the NTP server
org_time: time &log;
## Time at the server when the request arrived from the NTP client
rec_time: time &log;
## Time at the server when the response departed for the NTP client
xmt_time: time &log;
## Key used to designate a secret MD5 key
key_id: count &optional &log;
## MD5 hash computed over the key followed by the NTP packet header and extension fields
digest: string &optional &log;
## Number of extension fields (which are not currently parsed)
num_exts: count &default=0 &log;
## An integer specifying the command function. Values currently defined includes:
## 1 read status command/response
## 2 read variables command/response
## 3 write variables command/response
## 4 read clock variables command/response
## 5 write clock variables command/response
## 6 set trap address/port command/response
## 7 trap response
## Other values are reserved.
OpCode : count &log;
## The response bit. Set to zero for commands, one for responses.
resp_bit : bool &log;
## The error bit. Set to zero for normal response, one for error response.
err_bit : bool &log;
## The more bit. Set to zero for last fragment, one for all others.
more_bit : bool &log;
## The sequence number of the command or response
sequence : count &log;
## The current status of the system, peer or clock
status : count &log;
## A 16-bit integer identifying a valid association
association_id : count &log;
## An implementation-specific code which specifies the
## operation to be (which has been) performed and/or the
## format and semantics of the data included in the packet.
ReqCode : count &log;
## The authenticated bit. If set, this packet is authenticated.
auth_bit : bool &log;
## For a multipacket response, contains the sequence
## number of this packet. 0 is the first in the sequence,
## 127 (or less) is the last. The More Bit must be set in
## all packets but the last.
sequence : count &log;
## The number of the implementation this request code
## is defined by. An implementation number of zero is used
## for requst codes/data formats which all implementations
## agree on. Implementation number 255 is reserved (for
## extensions, in case we run out).
implementation : count &log;
## Must be 0 for a request. For a response, holds an error
## code relating to the request. If nonzero, the operation
## requested wasn't performed.
##
## 0 - no error
## 1 - incompatible implementation number
## 2 - unimplemented request code
## 3 - format error (wrong data items, data size, packet size etc.)
## 4 - no data available (e.g. request for details on unknown peer)
## 5-6 I don't know
## 7 - authentication failure (i.e. permission denied)
err : count &log;
}; };
## Event that can be handled to access the NTP record as it is sent on ## Event that can be handled to access the NTP record as it is sent on
## to the logging framework. ## to the logging framework.
global log_ntp: event(rec: Info); global log_ntp: event(rec: Info);
} }
redef record connection += { redef record connection += {
ntp: Info &optional; ntp: Info &optional;
}; };
const ports = { 123/udp };
redef likely_server_ports += { ports };
event zeek_init() &priority=5
{
Log::create_stream(NTP::LOG, [$columns=Info, $ev=log_ntp, $path="ntp"]);
Analyzer::register_for_ports(Analyzer::ANALYZER_NTP, ports);
}
event ntp_message(c: connection, is_orig: bool, msg: NTP::Message) &priority=5 event ntp_message(c: connection, is_orig: bool, msg: NTP::Message) &priority=5
{ {
# Record initialization
local info: Info; local info: Info;
if ( c?$ntp ) info$ts = network_time();
info = c$ntp; info$uid = c$uid;
else info$id = c$id;
{ info$version = msg$version;
info$ts = network_time(); info$mode = msg$mode;
info$uid = c$uid;
info$id = c$id;
info$ver = msg$version;
}
# From the request, we get the desired precision if ( msg$mode < 6 ) {
if ( is_orig ) info$stratum = msg$std_msg$stratum;
{ info$poll = msg$std_msg$poll;
info$precision = msg$precision; info$precision = msg$std_msg$precision;
c$ntp = info; info$root_delay = msg$std_msg$root_delay;
return; info$root_disp = msg$std_msg$root_disp;
}
# From the response, we fill out most of the rest of the fields. if ( info?$kiss_code)
info$stratum = msg$stratum; info$kiss_code = msg$std_msg$kiss_code;
info$org_time = msg$org_time; if ( info?$ref_id)
info$rec_time = msg$rec_time; info$ref_id = msg$std_msg$ref_id;
info$xmt_time = msg$xmt_time; if ( info?$ref_addr)
info$ref_addr = msg$std_msg$ref_addr;
if ( info?$ref_v6_hash_prefix)
info$ref_v6_hash_prefix = msg$std_msg$ref_v6_hash_prefix;
# Stratum 1 has the textual reference ID info$ref_time = msg$std_msg$ref_time;
if ( msg$stratum == 1 ) info$org_time = msg$std_msg$org_time;
info$ref_id = gsub(msg$ref_id, /\x00*/, ""); info$rec_time = msg$std_msg$rec_time;
info$xmt_time = msg$std_msg$xmt_time;
# Higher stratums using IPv4 have the address of the reference server. if ( info?$key_id)
if ( msg$stratum > 1 ) info$key_id = msg$std_msg$key_id;
{ if ( info?$digest)
if ( is_v4_addr(c$id$orig_h) ) info$digest = msg$std_msg$digest;
info$ref_clock = msg$ref_addr;
} info$num_exts = msg$std_msg$num_exts;
}
if ( msg$mode==6 ) {
info$OpCode = msg$control_msg$OpCode;
info$resp_bit = msg$control_msg$resp_bit;
info$err_bit = msg$control_msg$err_bit;
info$more_bit = msg$control_msg$more_bit;
info$sequence = msg$control_msg$sequence;
info$status = msg$control_msg$status;
info$association_id = msg$control_msg$association_id;
}
if ( msg$mode==7 ) {
info$ReqCode = msg$mode7_msg$ReqCode;
info$auth_bit = msg$mode7_msg$auth_bit;
info$sequence = msg$mode7_msg$sequence;
info$implementation = msg$mode7_msg$implementation;
info$err = msg$mode7_msg$err;
}
# Copy the present packet info into the connection record
# If more ntp packets are sent on the same connection, the newest one
# will overwrite the previous
c$ntp = info; c$ntp = info;
}
# Add the service to the Conn::LOG
add c$service["ntp"];
}
event ntp_message(c: connection, is_orig: bool, msg: NTP::Message) &priority=-5 event ntp_message(c: connection, is_orig: bool, msg: NTP::Message) &priority=-5
{ {
if ( ! is_orig ) # Log every ntp packet into ntp.log
{ Log::write(NTP::LOG, c$ntp);
Log::write(NTP::LOG, c$ntp); }
delete c$ntp;
}
}
event connection_state_remove(c: connection) &priority=-5 event zeek_init() &priority=5
{ {
if ( c?$ntp ) Analyzer::register_for_ports(Analyzer::ANALYZER_NTP, ports);
Log::write(NTP::LOG, c$ntp);
}
event ntp_mode6_message(c: connection, is_orig: bool, opcode: count) Log::create_stream(NTP::LOG, [$columns = Info, $ev = log_ntp]);
{ }
print "Mode 6", opcode;
}
event ntp_mode7_message(c: connection, is_orig: bool, opcode: count)
{
print "Mode 7", opcode;
}