Deleting scripts that aren't ready to be included.

- scan.bro and hot.conn.bro will be returning soon.

- The rest are going to return as updated protocol analysis
  scripts and new/updated frameworks later.
This commit is contained in:
Seth Hall 2011-09-27 14:40:11 -04:00
parent 827dcea586
commit 19f1e34408
5 changed files with 0 additions and 1054 deletions

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@ -1,3 +0,0 @@
# If we asked the Time Machine to capture, the filename prefix.
# TODO: implement this as a timemachine/notice.bro script?
#captured: string &optional;

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@ -1,98 +0,0 @@
##! This script makes it possible for the HTTP analysis scripts to analyze
##! the apparent normal case of "206 Partial Content" responses.
##!
##! This script doesn't work yet and isn't loaded by default.
@load base/frameworks/notice
@load ./main
@load ./utils
module HTTP;
export {
redef enum Notice::Type += {
Partial_Content_Out_Of_Order,
};
type Range: record {
from: count;
to: count;
} &log;
redef record Info += {
current_range: count &default=0;
request_ranges: vector of Range &optional;
response_range: Range &optional;
};
## Index is client IP address, server IP address, and URL being requested. The
## URL is tracked as part of the index in case multiple partial content segmented
## files are being transferred simultaneously between the server and client.
global partial_content_files: table[addr, addr, string] of Info &read_expire=5mins &redef;
}
event http_header(c: connection, is_orig: bool, name: string, value: string) &priority=2
{
local parts: table[count] of string;
if ( is_orig && name == "RANGE" )
{
# Example --> Range: bytes=1-1,2336-4951
parts = split(value, /[=]/);
if ( 2 in parts )
{
local ranges = split(parts[2], /,/);
for ( i in ranges )
{
if ( ! c$http?$request_ranges )
c$http$request_ranges = vector();
parts = split(ranges[i], /-/);
local r: Range = [$from=extract_count(parts[1]), $to=extract_count(parts[2])];
print r;
c$http$request_ranges[|c$http$request_ranges|] = r;
}
}
}
else if ( ! is_orig && name == "CONTENT-RANGE" )
{
# Example --> Content-Range: bytes 2336-4951/489528
parts = split(value, /[0-9]*/);
c$http$response_range = [$from=extract_count(parts[2]), $to=extract_count(parts[4])];
}
}
event http_reply(c: connection, version: string, code: count, reason: string) &priority=5
{
if ( code != 206 || ! c$http?$request_ranges )
return;
local url = build_url(c$http);
if ( [c$id$orig_h, c$id$resp_h, url] !in partial_content_files )
{
partial_content_files[c$id$orig_h, c$id$resp_h, url] = copy(c$http);
}
}
event http_entity_data(c: connection, is_orig: bool, length: count, data: string)
{
if ( is_orig || c$http$status_code != 206 || ! c$http?$request_ranges )
return;
local url = build_url(c$http);
local http = partial_content_files[c$id$orig_h, c$id$resp_h, url];
local range = http$request_ranges[http$current_range];
print http$current_range;
if ( http$current_range == 0 &&
c$http$response_range$from == 0 )
{
print "correct file beginning!";
}
}
event http_end_entity(c: connection, is_orig: bool)
{
print "end entity";
++c$http$current_range;
}

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#
# Log RPC request and reply messages. Does not in itself start/activate
# an analyzer. You need to load portmap and/or NFS for that
#
# TODO: maybe automatically load portmap, add a generic RPC analyzer and
# use expect connection, so that we can see RPC request/replies for RPC
# programs for which we don't have an analyzer.
#
@load base/utils/conn-ids
module RPC;
export {
global log_file = open_log_file("rpc") &redef;
# whether to match request to replies on the policy layer.
# (will report on rexmit and missing requests or replies)
global track_requests_replies = T &redef;
}
type rpc_call_state: enum {
NONE,
HAVE_CALL,
HAVE_REPLY
};
type rpc_call_info: record {
state: rpc_call_state;
calltime: time;
cid: conn_id;
};
function new_call(cid: conn_id): rpc_call_info
{
local ci: rpc_call_info;
ci$state = NONE;
ci$calltime = network_time();
ci$cid = cid;
return ci;
}
function rpc_expire_xid(t: table[count] of rpc_call_info, xid: count): interval
{
local ci = t[xid];
if (ci$state != HAVE_REPLY)
print log_file, fmt("%.6f %s %s note XID %d never recevied a reply",
ci$calltime, id_string(ci$cid),
get_port_transport_proto(ci$cid$orig_p), xid);
return 0 sec;
}
function new_xid_table(): table[count] of rpc_call_info
{
local inner: table[count] of rpc_call_info &write_expire=rpc_timeout &expire_func=rpc_expire_xid;
return inner;
}
# Match requests to replies.
# The analyzer does this indepently and might differ in timeouts and
# handling of xid reuse.
# FIXME: add timeouts. Note, we do clean up on connection_state_remove
global rpc_calls: table[conn_id] of table[count] of rpc_call_info;
# &write_expire = rpc_timeout &expire_func=expire_rpc_call;
event rpc_dialogue(c: connection, prog: count, ver: count, proc: count, status: rpc_status, start_time: time, call_len: count, reply_len: count)
{
# TODO: We currently do nothing here.
# using the rpc_call and rpc_reply events, is all we need.
}
event rpc_call(c: connection, xid: count, prog: count, ver: count, proc: count, call_len: count)
{
if (track_requests_replies)
{
if (c$id !in rpc_calls)
rpc_calls[c$id] = new_xid_table();
if (xid !in rpc_calls[c$id])
rpc_calls[c$id][xid] = new_call(c$id);
local curstate = rpc_calls[c$id][xid]$state;
if (curstate == HAVE_CALL)
print log_file, fmt("%.6f %s %s note XID %d call retransmitted",
network_time(), id_string(c$id), get_port_transport_proto(c$id$orig_p),
xid);
else if (curstate == HAVE_REPLY)
print log_file, fmt("%.6f %s %s note XID %d call received after reply",
network_time(), id_string(c$id), get_port_transport_proto(c$id$orig_p),
xid);
rpc_calls[c$id][xid]$state = HAVE_CALL;
}
print log_file, fmt("%.6f %s %s rpc_call %d %d %d %d %d",
network_time(), id_string(c$id), get_port_transport_proto(c$id$orig_p),
xid, prog, ver, proc, call_len);
}
event rpc_reply(c: connection, xid: count, status: rpc_status, reply_len: count)
{
if (track_requests_replies)
{
if (c$id !in rpc_calls)
rpc_calls[c$id] = new_xid_table();
if (xid !in rpc_calls[c$id])
{
rpc_calls[c$id][xid] = new_call(c$id);
# XXX: what to do about calltime in rpc_call_info??
}
if (rpc_calls[c$id][xid]$state == NONE)
print log_file, fmt("%.6f %s %s note XID %d reply but call is missing",
network_time(), id_string(c$id), get_port_transport_proto(c$id$orig_p),
xid);
else if (rpc_calls[c$id][xid]$state == HAVE_REPLY)
print log_file, fmt("%.6f %s %s note XID %d reply retransmitted",
network_time(), id_string(c$id), get_port_transport_proto(c$id$orig_p),
xid);
rpc_calls[c$id][xid]$state = HAVE_REPLY;
}
print log_file, fmt("%.6f %s %s rpc_reply %d %s %d",
network_time(), reverse_id_string(c$id), get_port_transport_proto(c$id$orig_p),
xid, status, reply_len);
}
function finish_calls(cid: conn_id)
{
for (xid in rpc_calls[cid])
rpc_expire_xid(rpc_calls[cid], xid);
}
event connection_state_remove(c: connection)
{
if (c$id !in rpc_calls)
return;
finish_calls(c$id);
delete rpc_calls[c$id];
}
event bro_done()
{
for (cid in rpc_calls)
finish_calls(cid);
}

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@load hot
redef enum Notice += {
Sensitive_Connection, # connection marked "hot"
};
# Whether to translate the local address in Sensitive_Connection notices
# to a hostname. Meant as a demonstration of the "when" construct.
const xlate_hot_local_addr = F &redef;
# The sets are indexed by the complete hot messages.
global hot_conns_reported: table[conn_id] of set[string];
const conn_closed = { TCP_CLOSED, TCP_RESET };
const state_graphic = {
["OTH"] = "?>?", ["REJ"] = "[",
["RSTO"] = ">]", ["RSTOS0"] = "}]", ["RSTR"] = ">[", ["RSTRH"] = "<[",
["S0"] = "}", ["S1"] = ">", ["S2"] = "}2", ["S3"] = "}3",
["SF"] = ">", ["SH"] = ">h", ["SHR"] = "<h",
};
function full_id_string(c: connection): string
{
local id = c$id;
local trans = get_port_transport_proto(id$orig_p);
local state = conn_state(c, trans);
local state_gr = state_graphic[state];
local service = service_name(c);
if ( state == "S0" || state == "S1" || state == "REJ" )
return fmt("%s %s %s/%s %s", id$orig_h, state_gr,
id$resp_h, service, c$addl);
else
return fmt("%s %sb %s %s/%s %sb %.1fs %s",
id$orig_h, conn_size(c$orig, trans),
state_gr, id$resp_h, service,
conn_size(c$resp, trans), c$duration, c$addl);
}
# Low-level routine that generates the actual Sensitive_Connection
# notice associated with a "hot" connection.
function do_hot_notice(c: connection, dir: string, host: string)
{
NOTICE([$note=Sensitive_Connection, $conn=c,
$msg=fmt("hot: %s %s local host: %s",
full_id_string(c), dir, host)]);
}
# Generate a Sensitive_Connection notice with the local hostname
# translated. Mostly intended as a demonstration of using "when".
function gen_hot_notice_with_hostnames(c: connection)
{
local id = c$id;
local inbound = is_local_addr(id$resp_h);
local dir = inbound ? "to" : "from";
local local_addr = inbound ? id$orig_h : id$resp_h;
add_notice_tag(c);
when ( local hostname = lookup_addr(local_addr) )
do_hot_notice(c, dir, hostname);
timeout 5 sec
{ do_hot_notice(c, dir, fmt("%s", local_addr)); }
}
function log_hot_conn(c: connection)
{
if ( c$id !in hot_conns_reported )
hot_conns_reported[c$id] = set() &mergeable;
local msg = full_id_string(c);
if ( msg !in hot_conns_reported[c$id] )
{
if ( xlate_hot_local_addr )
gen_hot_notice_with_hostnames(c);
else
NOTICE([$note=Sensitive_Connection, $conn=c,
$msg=fmt("hot: %s", full_id_string(c))]);
add hot_conns_reported[c$id][msg];
}
}
event connection_established(c: connection)
{
Hot::check_hot(c, Hot::CONN_ESTABLISHED);
if ( c$hot > 0 )
log_hot_conn(c);
}
event connection_state_remove(c: connection) &priority = -10
{
local os = c$orig$state;
local rs = c$resp$state;
if ( os == TCP_ESTABLISHED && rs == TCP_ESTABLISHED )
# It was still active, no summary generated.
connection_gone(c, "remove");
else if ( (os == TCP_CLOSED || rs == TCP_CLOSED) &&
(os == TCP_ESTABLISHED || rs == TCP_ESTABLISHED) )
# One side has closed, the other hasn't - it's in state S2
# or S3, hasn't been reported yet.
connection_gone(c, "remove");
delete hot_conns_reported[c$id];
}
event partial_connection(c: connection)
{
if ( c$orig$state == TCP_PARTIAL && c$resp$state == TCP_INACTIVE )
# This appears to be a stealth scan. Don't do hot-checking
# as there wasn't an established connection.
;
else
{
Hot::check_hot(c, Hot::CONN_ESTABLISHED);
Hot::check_hot(c, Hot::APPL_ESTABLISHED); # assume it's been established
}
if ( c$hot > 0 )
log_hot_conn(c);
}
event connection_attempt(c: connection)
{
Hot::check_spoof(c);
Hot::check_hot(c, Hot::CONN_ATTEMPTED);
}
event connection_finished(c: connection)
{
if ( c$orig$size == 0 || c$resp$size == 0 )
# Hard to get excited about this - not worth logging again.
c$hot = 0;
else
Hot::check_hot(c, Hot::CONN_FINISHED);
}
event connection_partial_close(c: connection)
{
if ( c$orig$size == 0 || c$resp$size == 0 )
# Hard to get excited about this - not worth logging again.
c$hot = 0;
else
Hot::check_hot(c, Hot::CONN_FINISHED);
}
event connection_half_finished(c: connection)
{
Hot::check_hot(c, Hot::CONN_ATTEMPTED);
}
event connection_rejected(c: connection)
{
Hot::check_hot(c, Hot::CONN_REJECTED);
}
event connection_reset(c: connection)
{
Hot::check_hot(c, Hot::CONN_FINISHED);
}
event connection_pending(c: connection)
{
if ( c$orig$state in conn_closed &&
(c$resp$state == TCP_INACTIVE || c$resp$state == TCP_PARTIAL) )
# This is a stray FIN or RST - don't bother reporting.
return;
if ( c$orig$state == TCP_RESET || c$resp$state == TCP_RESET )
# We already reported this connection when the RST
# occurred.
return;
Hot::check_hot(c, Hot::CONN_FINISHED);
}
function connection_gone(c: connection, gone_type: string)
{
if ( c$orig$size == 0 || c$resp$size == 0 )
{
if ( c$orig$state == TCP_RESET && c$resp$state == TCP_INACTIVE)
# A bare RST, no other context. Ignore it.
return;
# Hard to get excited about this - not worth logging again,
# per connection_finished().
c$hot = 0;
}
else
Hot::check_hot(c, Hot::CONN_TIMEOUT);
}

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@load base/frameworks/notice/main
@load port-name
module Scan;
export {
redef enum Notice::Type += {
## The source has scanned a number of ports.
PortScan,
## The source has scanned a number of addresses.
AddressScan,
## Apparent flooding backscatter seen from source.
BackscatterSeen,
## Summary of scanning activity.
ScanSummary,
## Summary of distinct ports per scanner.
PortScanSummary,
## Summary of distinct low ports per scanner.
LowPortScanSummary,
## Source touched a landmine destination.
Landmine,
## Source reached :bro:id:`Scan::shut_down_threshold`
ShutdownThreshold,
## Source touched privileged ports.
LowPortTrolling,
};
# Whether to consider UDP "connections" for scan detection.
# Can lead to false positives due to UDP fanout from some P2P apps.
const suppress_UDP_scan_checks = F &redef;
const activate_priv_port_check = T &redef;
const activate_landmine_check = F &redef;
const landmine_thresh_trigger = 5 &redef;
const landmine_address: set[addr] &redef;
const scan_summary_trigger = 25 &redef;
const port_summary_trigger = 20 &redef;
const lowport_summary_trigger = 10 &redef;
# Raise ShutdownThresh after this many failed attempts
const shut_down_threshold = 100 &redef;
# Which services should be analyzed when detecting scanning
# (not consulted if analyze_all_services is set).
const analyze_services: set[port] &redef;
const analyze_all_services = T &redef;
# Track address scaners only if at least these many hosts contacted.
const addr_scan_trigger = 0 &redef;
# Ignore address scanners for further scan detection after
# scanning this many hosts.
# 0 disables.
const ignore_scanners_threshold = 0 &redef;
# Report a scan of peers at each of these points.
const report_peer_scan: vector of count = {
20, 100, 1000, 10000, 50000, 100000, 250000, 500000, 1000000,
} &redef;
const report_outbound_peer_scan: vector of count = {
100, 1000, 10000,
} &redef;
# Report a scan of ports at each of these points.
const report_port_scan: vector of count = {
50, 250, 1000, 5000, 10000, 25000, 65000,
} &redef;
# Once a source has scanned this many different ports (to however many
# different remote hosts), start tracking its per-destination access.
const possible_port_scan_thresh = 20 &redef;
# Threshold for scanning privileged ports.
const priv_scan_trigger = 5 &redef;
const troll_skip_service = {
smtp, ftp, ssh, 20/tcp, http,
} &redef;
const report_accounts_tried: vector of count = {
20, 100, 1000, 10000, 100000, 1000000,
} &redef;
const report_remote_accounts_tried: vector of count = {
100, 500,
} &redef;
# Report a successful password guessing if the source attempted
# at least this many.
const password_guessing_success_threshhold = 20 &redef;
const skip_accounts_tried: set[addr] &redef;
const addl_web = {
81/tcp, 443/tcp, 8000/tcp, 8001/tcp, 8080/tcp, }
&redef;
const skip_services = { ident, } &redef;
const skip_outbound_services = { Hot::allow_services, ftp, addl_web, }
&redef;
const skip_scan_sources = {
255.255.255.255, # who knows why we see these, but we do
# AltaVista. Here just as an example of what sort of things
# you might list.
test-scooter.av.pa-x.dec.com,
} &redef;
const skip_scan_nets: set[subnet] = {} &redef;
# List of well known local server/ports to exclude for scanning
# purposes.
const skip_dest_server_ports: set[addr, port] = {} &redef;
# Reverse (SYN-ack) scans seen from these ports are considered
# to reflect possible SYN-flooding backscatter, and not true
# (stealth) scans.
const backscatter_ports = {
http, 53/tcp, 53/udp, bgp, 6666/tcp, 6667/tcp,
} &redef;
const report_backscatter: vector of count = {
20,
} &redef;
global check_scan:
function(c: connection, established: bool, reverse: bool): bool;
# The following tables are defined here so that we can redef
# the expire timeouts.
# FIXME: should we allow redef of attributes on IDs which
# are not exported?
# How many different hosts connected to with a possible
# backscatter signature.
global distinct_backscatter_peers: table[addr] of table[addr] of count
&read_expire = 15 min;
# Expire functions that trigger summaries.
global scan_summary:
function(t: table[addr] of set[addr], orig: addr): interval;
global port_summary:
function(t: table[addr] of set[port], orig: addr): interval;
global lowport_summary:
function(t: table[addr] of set[port], orig: addr): interval;
# Indexed by scanner address, yields # distinct peers scanned.
# pre_distinct_peers tracks until addr_scan_trigger hosts first.
global pre_distinct_peers: table[addr] of set[addr]
&read_expire = 15 mins &redef;
global distinct_peers: table[addr] of set[addr]
&read_expire = 15 mins &expire_func=scan_summary &redef;
global distinct_ports: table[addr] of set[port]
&read_expire = 15 mins &expire_func=port_summary &redef;
global distinct_low_ports: table[addr] of set[port]
&read_expire = 15 mins &expire_func=lowport_summary &redef;
# Indexed by scanner address, yields a table with scanned hosts
# (and ports).
global scan_triples: table[addr] of table[addr] of set[port];
global remove_possible_source:
function(s: set[addr], idx: addr): interval;
global possible_scan_sources: set[addr]
&expire_func=remove_possible_source &read_expire = 15 mins;
# Indexed by source address, yields user name & password tried.
global accounts_tried: table[addr] of set[string, string]
&read_expire = 1 days;
global ignored_scanners: set[addr] &create_expire = 1 day &redef;
# These tables track whether a threshold has been reached.
# More precisely, the counter is the next index of threshold vector.
global shut_down_threshold_reached: table[addr] of bool &default=F;
global rb_idx: table[addr] of count
&default=0 &read_expire = 1 days &redef;
global rps_idx: table[addr] of count
&default=0 &read_expire = 1 days &redef;
global rops_idx: table[addr] of count
&default=0 &read_expire = 1 days &redef;
global rpts_idx: table[addr,addr] of count
&default=0 &read_expire = 1 days &redef;
global rat_idx: table[addr] of count
&default=0 &read_expire = 1 days &redef;
global rrat_idx: table[addr] of count
&default=0 &read_expire = 1 days &redef;
}
global thresh_check: function(v: vector of count, idx: table[addr] of count,
orig: addr, n: count): bool;
global thresh_check_2: function(v: vector of count,
idx: table[addr,addr] of count, orig: addr,
resp: addr, n: count): bool;
function scan_summary(t: table[addr] of set[addr], orig: addr): interval
{
local num_distinct_peers = orig in t ? |t[orig]| : 0;
if ( num_distinct_peers >= scan_summary_trigger )
NOTICE([$note=ScanSummary, $src=orig, $n=num_distinct_peers,
$msg=fmt("%s scanned a total of %d hosts",
orig, num_distinct_peers)]);
return 0 secs;
}
function port_summary(t: table[addr] of set[port], orig: addr): interval
{
local num_distinct_ports = orig in t ? |t[orig]| : 0;
if ( num_distinct_ports >= port_summary_trigger )
NOTICE([$note=PortScanSummary, $src=orig, $n=num_distinct_ports,
$msg=fmt("%s scanned a total of %d ports",
orig, num_distinct_ports)]);
return 0 secs;
}
function lowport_summary(t: table[addr] of set[port], orig: addr): interval
{
local num_distinct_lowports = orig in t ? |t[orig]| : 0;
if ( num_distinct_lowports >= lowport_summary_trigger )
NOTICE([$note=LowPortScanSummary, $src=orig,
$n=num_distinct_lowports,
$msg=fmt("%s scanned a total of %d low ports",
orig, num_distinct_lowports)]);
return 0 secs;
}
function clear_addr(a: addr)
{
delete distinct_peers[a];
delete distinct_ports[a];
delete distinct_low_ports[a];
delete scan_triples[a];
delete possible_scan_sources[a];
delete distinct_backscatter_peers[a];
delete pre_distinct_peers[a];
delete rb_idx[a];
delete rps_idx[a];
delete rops_idx[a];
delete rat_idx[a];
delete rrat_idx[a];
delete shut_down_threshold_reached[a];
delete ignored_scanners[a];
}
function ignore_addr(a: addr)
{
clear_addr(a);
add ignored_scanners[a];
}
function check_scan(c: connection, established: bool, reverse: bool): bool
{
local id = c$id;
local service = "ftp-data" in c$service ? 20/tcp
: (reverse ? id$orig_p : id$resp_p);
local rev_service = reverse ? id$resp_p : id$orig_p;
local orig = reverse ? id$resp_h : id$orig_h;
local resp = reverse ? id$orig_h : id$resp_h;
local outbound = is_local_addr(orig);
# The following works better than using get_conn_transport_proto()
# because c might not correspond to an active connection (which
# causes the function to fail).
if ( suppress_UDP_scan_checks &&
service >= 0/udp && service <= 65535/udp )
return F;
if ( service in skip_services && ! outbound )
return F;
if ( outbound && service in skip_outbound_services )
return F;
if ( orig in skip_scan_sources )
return F;
if ( orig in skip_scan_nets )
return F;
# Don't include well known server/ports for scanning purposes.
if ( ! outbound && [resp, service] in skip_dest_server_ports )
return F;
if ( orig in ignored_scanners)
return F;
if ( (! established || service !in Hot::allow_services) &&
# not established, service not expressly allowed
# not known peer set
(orig !in distinct_peers || resp !in distinct_peers[orig]) &&
# want to consider service for scan detection
(analyze_all_services || service in analyze_services) )
{
if ( reverse && rev_service in backscatter_ports &&
# reverse, non-priv backscatter port
service >= 1024/tcp )
{
if ( orig !in distinct_backscatter_peers )
{
local empty_bs_table:
table[addr] of count &default=0;
distinct_backscatter_peers[orig] =
empty_bs_table;
}
if ( ++distinct_backscatter_peers[orig][resp] <= 2 &&
# The test is <= 2 because we get two check_scan()
# calls, once on connection attempt and once on
# tear-down.
distinct_backscatter_peers[orig][resp] == 1 &&
# Looks like backscatter, and it's not scanning
# a privileged port.
thresh_check(report_backscatter, rb_idx, orig,
|distinct_backscatter_peers[orig]|)
)
{
local rev_svc = rev_service in port_names ?
port_names[rev_service] :
fmt("%s", rev_service);
NOTICE([$note=BackscatterSeen, $src=orig,
$p=rev_service,
$msg=fmt("backscatter seen from %s (%d hosts; %s)",
orig, |distinct_backscatter_peers[orig]|, rev_svc)]);
}
if ( ignore_scanners_threshold > 0 &&
|distinct_backscatter_peers[orig]| >
ignore_scanners_threshold )
ignore_addr(orig);
}
else
{ # done with backscatter check
local ignore = F;
local svc = service in port_names ?
port_names[service] : fmt("%s", service);
if ( orig !in distinct_peers && addr_scan_trigger > 0 )
{
if ( orig !in pre_distinct_peers )
pre_distinct_peers[orig] = set();
add pre_distinct_peers[orig][resp];
if ( |pre_distinct_peers[orig]| < addr_scan_trigger )
ignore = T;
}
if ( ! ignore )
{ # XXXXX
if ( orig !in distinct_peers )
distinct_peers[orig] = set() &mergeable;
if ( resp !in distinct_peers[orig] )
add distinct_peers[orig][resp];
local n = |distinct_peers[orig]|;
if ( activate_landmine_check &&
n >= landmine_thresh_trigger &&
mask_addr(resp, 24) in landmine_address )
{
local msg2 = fmt("landmine address trigger %s%s ", orig, svc);
NOTICE([$note=Landmine, $src=orig,
$p=service, $msg=msg2]);
}
# Check for threshold if not outbound.
if ( ! shut_down_threshold_reached[orig] &&
n >= shut_down_threshold &&
! outbound && orig !in neighbor_nets )
{
shut_down_threshold_reached[orig] = T;
local msg = fmt("shutdown threshold reached for %s", orig);
NOTICE([$note=ShutdownThreshold, $src=orig,
$p=service, $msg=msg]);
}
else
{
local address_scan = F;
if ( outbound &&
# inside host scanning out?
thresh_check(report_outbound_peer_scan, rops_idx, orig, n) )
address_scan = T;
if ( ! outbound &&
thresh_check(report_peer_scan, rps_idx, orig, n) )
address_scan = T;
if ( address_scan )
NOTICE([$note=AddressScan,
$src=orig, $p=service,
$n=n,
$msg=fmt("%s has scanned %d hosts (%s)",
orig, n, svc)]);
if ( address_scan &&
ignore_scanners_threshold > 0 &&
n > ignore_scanners_threshold )
ignore_addr(orig);
}
}
} # XXXX
}
if ( established )
# Don't consider established connections for port scanning,
# it's too easy to be mislead by FTP-like applications that
# legitimately gobble their way through the port space.
return F;
# Coarse search for port-scanning candidates: those that have made
# connections (attempts) to possible_port_scan_thresh or more
# distinct ports.
if ( orig !in distinct_ports || service !in distinct_ports[orig] )
{
if ( orig !in distinct_ports )
distinct_ports[orig] = set() &mergeable;
if ( service !in distinct_ports[orig] )
add distinct_ports[orig][service];
if ( |distinct_ports[orig]| >= possible_port_scan_thresh &&
orig !in scan_triples )
{
scan_triples[orig] = table() &mergeable;
add possible_scan_sources[orig];
}
}
# For sources that have been identified as possible scan sources,
# keep track of per-host scanning.
if ( orig in possible_scan_sources )
{
if ( orig !in scan_triples )
scan_triples[orig] = table() &mergeable;
if ( resp !in scan_triples[orig] )
scan_triples[orig][resp] = set() &mergeable;
if ( service !in scan_triples[orig][resp] )
{
add scan_triples[orig][resp][service];
if ( thresh_check_2(report_port_scan, rpts_idx,
orig, resp,
|scan_triples[orig][resp]|) )
{
local m = |scan_triples[orig][resp]|;
NOTICE([$note=PortScan, $n=m, $src=orig,
$p=service,
$msg=fmt("%s has scanned %d ports of %s", orig, m, resp)]);
}
}
}
return T;
}
# Hook into the catch&release dropping. When an address gets restored, we reset
# the source to allow dropping it again.
event Drop::address_restored(a: addr)
{
#Drop::debug_log(fmt("received restored for %s (scan.bro)", a));
clear_addr(a);
}
event Drop::address_cleared(a: addr)
{
#Drop::debug_log(fmt("received cleared for %s (scan.bro)", a));
clear_addr(a);
}
# When removing a possible scan source, we automatically delete its scanned
# hosts and ports. But we do not want the deletion propagated, because every
# peer calls the expire_function on its own (and thus applies the delete
# operation on its own table).
function remove_possible_source(s: set[addr], idx: addr): interval
{
suspend_state_updates();
delete scan_triples[idx];
resume_state_updates();
return 0 secs;
}
# To recognize whether a certain threshhold vector (e.g. report_peer_scans)
# has been transgressed, a global variable containing the next vector index
# (idx) must be incremented. This cumbersome mechanism is necessary because
# values naturally don't increment by one (e.g. replayed table merges).
function thresh_check(v: vector of count, idx: table[addr] of count,
orig: addr, n: count): bool
{
if ( ignore_scanners_threshold > 0 && n > ignore_scanners_threshold )
{
ignore_addr(orig);
return F;
}
if ( idx[orig] < |v| && n >= v[idx[orig]] )
{
++idx[orig];
return T;
}
else
return F;
}
# Same as above, except the index has a different type signature.
function thresh_check_2(v: vector of count, idx: table[addr, addr] of count,
orig: addr, resp: addr, n: count): bool
{
if ( ignore_scanners_threshold > 0 && n > ignore_scanners_threshold )
{
ignore_addr(orig);
return F;
}
if ( idx[orig,resp] < |v| && n >= v[idx[orig, resp]] )
{
++idx[orig,resp];
return T;
}
else
return F;
}
event connection_established(c: connection)
{
local is_reverse_scan = (c$orig$state == TCP_INACTIVE);
Scan::check_scan(c, T, is_reverse_scan);
}
event partial_connection(c: connection)
{
Scan::check_scan(c, T, F);
}
event connection_attempt(c: connection)
{
Scan::check_scan(c, F, c$orig$state == TCP_INACTIVE);
}
event connection_half_finished(c: connection)
{
# Half connections never were "established", so do scan-checking here.
Scan::check_scan(c, F, F);
}
event connection_rejected(c: connection)
{
local is_reverse_scan = c$orig$state == TCP_RESET;
Scan::check_scan(c, F, is_reverse_scan);
}
event connection_reset(c: connection)
{
if ( c$orig$state == TCP_INACTIVE || c$resp$state == TCP_INACTIVE )
# We never heard from one side - that looks like a scan.
Scan::check_scan(c, c$orig$size + c$resp$size > 0,
c$orig$state == TCP_INACTIVE);
}
event connection_pending(c: connection)
{
if ( c$orig$state == TCP_PARTIAL && c$resp$state == TCP_INACTIVE )
Scan::check_scan(c, F, F);
}
# Report the remaining entries in the tables.
event bro_done()
{
for ( orig in distinct_peers )
scan_summary(distinct_peers, orig);
for ( orig in distinct_ports )
port_summary(distinct_ports, orig);
for ( orig in distinct_low_ports )
lowport_summary(distinct_low_ports, orig);
}