mirror of
https://github.com/zeek/zeek.git
synced 2025-10-02 06:38:20 +00:00
Change dns.log to include only standard DNS queries.
The scope of dns.log is now only standard queries (OPCODE == 0). Other kinds of queries (e.g. inverse query) were not handled correctly and could interfere with the state tracking of the default DNS scripts.
This commit is contained in:
Jon Siwek
parent
0e0e74e49c
commit
31866f8f59
14 changed files with 44 additions and 39 deletions
|
|
@ -1,5 +1,5 @@
|
|||
@load base/protocols/conn
|
||||
@load base/protocols/dns
|
||||
@load base/protocols/http
|
||||
|
||||
event connection_state_remove(c: connection)
|
||||
{
|
||||
|
|
|
|||
|
|
@ -232,7 +232,7 @@ overly populated.
|
|||
|
||||
.. btest:: connection-record-01
|
||||
|
||||
@TEST-EXEC: btest-rst-cmd bro -b -r ${TRACES}/dns-session.trace ${DOC_ROOT}/scripting/connection_record_01.bro
|
||||
@TEST-EXEC: btest-rst-cmd bro -b -r ${TRACES}/http/get.trace ${DOC_ROOT}/scripting/connection_record_01.bro
|
||||
|
||||
As you can see from the output, the connection record is something of
|
||||
a jumble when printed on its own. Regularly taking a peek at a
|
||||
|
|
@ -248,9 +248,9 @@ originating host is referenced by ``c$id$orig_h`` which if given a
|
|||
narrative relates to ``orig_h`` which is a member of ``id`` which is
|
||||
a member of the data structure referred to as ``c`` that was passed
|
||||
into the event handler." Given that the responder port
|
||||
(``c$id$resp_p``) is ``53/tcp``, it's likely that Bro's base DNS scripts
|
||||
(``c$id$resp_p``) is ``53/tcp``, it's likely that Bro's base HTTP scripts
|
||||
can further populate the connection record. Let's load the
|
||||
``base/protocols/dns`` scripts and check the output of our script.
|
||||
``base/protocols/http`` scripts and check the output of our script.
|
||||
|
||||
Bro uses the dollar sign as its field delimiter and a direct
|
||||
correlation exists between the output of the connection record and the
|
||||
|
|
@ -262,16 +262,16 @@ brackets, which would correspond to the ``$``-delimiter in a Bro script.
|
|||
|
||||
.. btest:: connection-record-02
|
||||
|
||||
@TEST-EXEC: btest-rst-cmd bro -b -r ${TRACES}/dns-session.trace ${DOC_ROOT}/scripting/connection_record_02.bro
|
||||
@TEST-EXEC: btest-rst-cmd bro -b -r ${TRACES}/http/get.trace ${DOC_ROOT}/scripting/connection_record_02.bro
|
||||
|
||||
The addition of the ``base/protocols/dns`` scripts populates the
|
||||
``dns=[]`` member of the connection record. While Bro is doing a
|
||||
The addition of the ``base/protocols/http`` scripts populates the
|
||||
``http=[]`` member of the connection record. While Bro is doing a
|
||||
massive amount of work in the background, it is in what is commonly
|
||||
called "scriptland" that details are being refined and decisions
|
||||
being made. Were we to continue running in "bare mode" we could slowly
|
||||
keep adding infrastructure through ``@load`` statements. For example,
|
||||
were we to ``@load base/frameworks/logging``, Bro would generate a
|
||||
``conn.log`` and ``dns.log`` for us in the current working directory.
|
||||
``conn.log`` and ``http.log`` for us in the current working directory.
|
||||
As mentioned above, including the appropriate ``@load`` statements is
|
||||
not only good practice, but can also help to indicate which
|
||||
functionalities are being used in a script. Take a second to run the
|
||||
|
|
|
|||
|
|
@ -206,6 +206,10 @@ hook set_session(c: connection, msg: dns_msg, is_query: bool) &priority=5
|
|||
|
||||
event dns_message(c: connection, is_orig: bool, msg: dns_msg, len: count) &priority=5
|
||||
{
|
||||
if ( msg$opcode != 0 )
|
||||
# Currently only standard queries are tracked.
|
||||
return;
|
||||
|
||||
hook set_session(c, msg, is_orig);
|
||||
|
||||
if ( msg$QR && msg$rcode != 0 && msg$num_queries == 0 )
|
||||
|
|
@ -214,6 +218,10 @@ event dns_message(c: connection, is_orig: bool, msg: dns_msg, len: count) &prior
|
|||
|
||||
event DNS::do_reply(c: connection, msg: dns_msg, ans: dns_answer, reply: string) &priority=5
|
||||
{
|
||||
if ( msg$opcode != 0 )
|
||||
# Currently only standard queries are tracked.
|
||||
return;
|
||||
|
||||
if ( ! msg$QR )
|
||||
# This is weird: the inquirer must also be providing answers in
|
||||
# the request, which is not what we want to track.
|
||||
|
|
@ -249,7 +257,7 @@ event DNS::do_reply(c: connection, msg: dns_msg, ans: dns_answer, reply: string)
|
|||
|
||||
event DNS::do_reply(c: connection, msg: dns_msg, ans: dns_answer, reply: string) &priority=-5
|
||||
{
|
||||
if ( c$dns$ready )
|
||||
if ( c?$dns && c$dns$ready )
|
||||
{
|
||||
Log::write(DNS::LOG, c$dns);
|
||||
# This record is logged and no longer pending.
|
||||
|
|
@ -260,6 +268,10 @@ event DNS::do_reply(c: connection, msg: dns_msg, ans: dns_answer, reply: string)
|
|||
|
||||
event dns_request(c: connection, msg: dns_msg, query: string, qtype: count, qclass: count) &priority=5
|
||||
{
|
||||
if ( msg$opcode != 0 )
|
||||
# Currently only standard queries are tracked.
|
||||
return;
|
||||
|
||||
c$dns$RD = msg$RD;
|
||||
c$dns$TC = msg$TC;
|
||||
c$dns$qclass = qclass;
|
||||
|
|
@ -356,7 +368,8 @@ event dns_SRV_reply(c: connection, msg: dns_msg, ans: dns_answer) &priority=5
|
|||
|
||||
event dns_rejected(c: connection, msg: dns_msg, query: string, qtype: count, qclass: count) &priority=5
|
||||
{
|
||||
c$dns$rejected = T;
|
||||
if ( c?$dns )
|
||||
c$dns$rejected = T;
|
||||
}
|
||||
|
||||
event connection_state_remove(c: connection) &priority=-5
|
||||
|
|
|
|||
|
|
@ -21,6 +21,10 @@ export {
|
|||
|
||||
event DNS::do_reply(c: connection, msg: dns_msg, ans: dns_answer, reply: string) &priority=4
|
||||
{
|
||||
if ( msg$opcode != 0 )
|
||||
# Currently only standard queries are tracked.
|
||||
return;
|
||||
|
||||
# The "ready" flag will be set here. This causes the setting from the
|
||||
# base script to be overridden since the base script will log immediately
|
||||
# after all of the ANS replies have been seen.
|
||||
|
|
|
|||
|
|
@ -4,10 +4,10 @@
|
|||
:linenos:
|
||||
:emphasize-lines: 1,1
|
||||
|
||||
# bro -b -r dns-session.trace connection_record_01.bro
|
||||
[id=[orig_h=212.180.42.100, orig_p=25000/tcp, resp_h=131.243.64.3, resp_p=53/tcp], orig=[size=29, state=5, num_pkts=6, num_bytes_ip=273, flow_label=0], resp=[size=44, state=5, num_pkts=5, num_bytes_ip=248, flow_label=0], start_time=930613226.067666, duration=0.709643, service={
|
||||
# bro -b -r http/get.trace connection_record_01.bro
|
||||
[id=[orig_h=141.142.228.5, orig_p=59856/tcp, resp_h=192.150.187.43, resp_p=80/tcp], orig=[size=136, state=5, num_pkts=7, num_bytes_ip=512, flow_label=0], resp=[size=5007, state=5, num_pkts=7, num_bytes_ip=5379, flow_label=0], start_time=1362692526.869344, duration=0.211484, service={
|
||||
|
||||
}, addl=, hot=0, history=ShADadFf, uid=CXWv6p3arKYeMETxOg, tunnel=<uninitialized>, conn=[ts=930613226.067666, uid=CXWv6p3arKYeMETxOg, id=[orig_h=212.180.42.100, orig_p=25000/tcp, resp_h=131.243.64.3, resp_p=53/tcp], proto=tcp, service=<uninitialized>, duration=0.709643, orig_bytes=29, resp_bytes=44, conn_state=SF, local_orig=<uninitialized>, missed_bytes=0, history=ShADadFf, orig_pkts=6, orig_ip_bytes=273, resp_pkts=5, resp_ip_bytes=248, tunnel_parents={
|
||||
}, addl=, hot=0, history=ShADadFf, uid=CXWv6p3arKYeMETxOg, tunnel=<uninitialized>, conn=[ts=1362692526.869344, uid=CXWv6p3arKYeMETxOg, id=[orig_h=141.142.228.5, orig_p=59856/tcp, resp_h=192.150.187.43, resp_p=80/tcp], proto=tcp, service=<uninitialized>, duration=0.211484, orig_bytes=136, resp_bytes=5007, conn_state=SF, local_orig=<uninitialized>, missed_bytes=0, history=ShADadFf, orig_pkts=7, orig_ip_bytes=512, resp_pkts=7, resp_ip_bytes=5379, tunnel_parents={
|
||||
|
||||
}], extract_orig=F, extract_resp=F]
|
||||
|
||||
|
|
|
|||
|
|
@ -4,16 +4,14 @@
|
|||
:linenos:
|
||||
:emphasize-lines: 1,1
|
||||
|
||||
# bro -b -r dns-session.trace connection_record_02.bro
|
||||
[id=[orig_h=212.180.42.100, orig_p=25000/tcp, resp_h=131.243.64.3, resp_p=53/tcp], orig=[size=29, state=5, num_pkts=6, num_bytes_ip=273, flow_label=0], resp=[size=44, state=5, num_pkts=5, num_bytes_ip=248, flow_label=0], start_time=930613226.067666, duration=0.709643, service={
|
||||
# bro -b -r http/get.trace connection_record_02.bro
|
||||
[id=[orig_h=141.142.228.5, orig_p=59856/tcp, resp_h=192.150.187.43, resp_p=80/tcp], orig=[size=136, state=5, num_pkts=7, num_bytes_ip=512, flow_label=0], resp=[size=5007, state=5, num_pkts=7, num_bytes_ip=5379, flow_label=0], start_time=1362692526.869344, duration=0.211484, service={
|
||||
|
||||
}, addl=, hot=0, history=ShADadFf, uid=CXWv6p3arKYeMETxOg, tunnel=<uninitialized>, conn=[ts=930613226.067666, uid=CXWv6p3arKYeMETxOg, id=[orig_h=212.180.42.100, orig_p=25000/tcp, resp_h=131.243.64.3, resp_p=53/tcp], proto=tcp, service=<uninitialized>, duration=0.709643, orig_bytes=29, resp_bytes=44, conn_state=SF, local_orig=<uninitialized>, missed_bytes=0, history=ShADadFf, orig_pkts=6, orig_ip_bytes=273, resp_pkts=5, resp_ip_bytes=248, tunnel_parents={
|
||||
}, addl=, hot=0, history=ShADadFf, uid=CXWv6p3arKYeMETxOg, tunnel=<uninitialized>, conn=[ts=1362692526.869344, uid=CXWv6p3arKYeMETxOg, id=[orig_h=141.142.228.5, orig_p=59856/tcp, resp_h=192.150.187.43, resp_p=80/tcp], proto=tcp, service=<uninitialized>, duration=0.211484, orig_bytes=136, resp_bytes=5007, conn_state=SF, local_orig=<uninitialized>, missed_bytes=0, history=ShADadFf, orig_pkts=7, orig_ip_bytes=512, resp_pkts=7, resp_ip_bytes=5379, tunnel_parents={
|
||||
|
||||
}], extract_orig=F, extract_resp=F, dns=<uninitialized>, dns_state=[pending={
|
||||
[34798] = [initialized=T, vals={
|
||||
}], extract_orig=F, extract_resp=F, http=[ts=1362692526.939527, uid=CXWv6p3arKYeMETxOg, id=[orig_h=141.142.228.5, orig_p=59856/tcp, resp_h=192.150.187.43, resp_p=80/tcp], trans_depth=1, method=GET, host=bro.org, uri=/download/CHANGES.bro-aux.txt, referrer=<uninitialized>, user_agent=Wget/1.14 (darwin12.2.0), request_body_len=0, response_body_len=4705, status_code=200, status_msg=OK, info_code=<uninitialized>, info_msg=<uninitialized>, filename=<uninitialized>, tags={
|
||||
|
||||
}, settings=[max_len=<uninitialized>], top=1, bottom=1, size=0]
|
||||
}, finished_answers={
|
||||
}, username=<uninitialized>, password=<uninitialized>, capture_password=F, proxied=<uninitialized>, range_request=F, orig_fuids=<uninitialized>, orig_mime_types=<uninitialized>, resp_fuids=[FakNcS1Jfe01uljb3], resp_mime_types=[text/plain], current_entity=<uninitialized>, orig_mime_depth=1, resp_mime_depth=1], http_state=[pending={
|
||||
|
||||
}]]
|
||||
}, current_request=1, current_response=1]]
|
||||
|
||||
|
|
|
|||
|
|
@ -3,7 +3,7 @@
|
|||
connection_record_02.bro
|
||||
|
||||
@load base/protocols/conn
|
||||
@load base/protocols/dns
|
||||
@load base/protocols/http
|
||||
|
||||
event connection_state_remove(c: connection)
|
||||
{
|
||||
|
|
|
|||
|
|
@ -1,10 +0,0 @@
|
|||
#separator \x09
|
||||
#set_separator ,
|
||||
#empty_field (empty)
|
||||
#unset_field -
|
||||
#path dns
|
||||
#open 2013-08-26-19-04-37
|
||||
#fields ts uid id.orig_h id.orig_p id.resp_h id.resp_p proto trans_id query qclass qclass_name qtype qtype_name rcode rcode_name AA TC RD RA Z answers TTLs rejected auth addl
|
||||
#types time string addr port addr port enum count string count string count string count string bool bool bool bool count vector[string] vector[interval] bool table[string] table[string]
|
||||
930613226.518174 CXWv6p3arKYeMETxOg 212.180.42.100 25000 131.243.64.3 53 tcp 34798 - - - - - 0 NOERROR F F F T 0 4.3.2.1 31337.000000 F - -
|
||||
#close 2013-08-26-19-04-37
|
||||
|
|
@ -1 +1 @@
|
|||
@TEST-EXEC: btest-rst-cmd bro -b -r ${TRACES}/dns-session.trace ${DOC_ROOT}/scripting/connection_record_01.bro
|
||||
@TEST-EXEC: btest-rst-cmd bro -b -r ${TRACES}/http/get.trace ${DOC_ROOT}/scripting/connection_record_01.bro
|
||||
|
|
|
|||
|
|
@ -1 +1 @@
|
|||
@TEST-EXEC: btest-rst-cmd bro -b -r ${TRACES}/dns-session.trace ${DOC_ROOT}/scripting/connection_record_02.bro
|
||||
@TEST-EXEC: btest-rst-cmd bro -b -r ${TRACES}/http/get.trace ${DOC_ROOT}/scripting/connection_record_02.bro
|
||||
|
|
|
|||
|
|
@ -3,7 +3,7 @@
|
|||
connection_record_02.bro
|
||||
|
||||
@load base/protocols/conn
|
||||
@load base/protocols/dns
|
||||
@load base/protocols/http
|
||||
|
||||
event connection_state_remove(c: connection)
|
||||
{
|
||||
|
|
|
|||
|
|
@ -1,4 +0,0 @@
|
|||
# @TEST-EXEC: bro -r $TRACES/dns-session.trace %INPUT
|
||||
# @TEST-EXEC: btest-diff dns.log
|
||||
|
||||
@load protocols/dns/auth-addl
|
||||
|
|
@ -0,0 +1,4 @@
|
|||
# @TEST-EXEC: bro -r $TRACES/dns-inverse-query.trace %INPUT
|
||||
# @TEST-EXEC: test ! -e dns.log
|
||||
|
||||
@load protocols/dns/auth-addl
|
||||
Loading…
Add table
Add a link
Reference in a new issue