Mirror/zeek
1
0
Fork 0
mirror of https://github.com/zeek/zeek.git synced 2025-10-02 14:48:21 +00:00
Code Issues Projects Releases Packages Wiki Activity Actions 2

Merge branch 'master' into topic/jsiwek/reorg-followup

Browse source 
Conflicts:
	scripts/base/frameworks/cluster/setup-connections.bro
	scripts/base/protocols/ssh/main.bro
This commit is contained in:
Jon Siwek 2011-08-11 10:56:20 -05:00
commit 59e5fc5633
18 changed files with 363 additions and 199 deletions
Download patch file Download diff file Expand all files Collapse all files

53
scripts/base/protocols/smtp/main.bro
View file

@ -7,13 +7,6 @@ module SMTP;
export {
redef enum Log::ID += { SMTP };
redef enum Notice::Type += {
## Indicates that the server sent a reply mentioning an SMTP block list.
BL_Error_Message,
## Indicates the client's address is seen in the block list error message.
BL_Blocked_Host,
};
type Info: record {
ts: time &log;
uid: string &log;
@ -62,26 +55,7 @@ export {
## ALL_HOSTS - always capture the entire path.
## NO_HOSTS - never capture the path.
const mail_path_capture = ALL_HOSTS &redef;
# This matches content in SMTP error messages that indicate some
# block list doesn't like the connection/mail.
const bl_error_messages =
/spamhaus\.org\//
| /sophos\.com\/security\//
| /spamcop\.net\/bl/
| /cbl\.abuseat\.org\//
| /sorbs\.net\//
| /bsn\.borderware\.com\//
| /mail-abuse\.com\//
| /b\.barracudacentral\.com\//
| /psbl\.surriel\.com\//
| /antispam\.imp\.ch\//
| /dyndns\.com\/.*spam/
| /rbl\.knology\.net\//
| /intercept\.datapacket\.net\//
| /uceprotect\.net\//
| /hostkarma\.junkemailfilter\.com\// &redef;
global log_smtp: event(rec: Info);
## Configure the default ports for SMTP analysis.
@ -184,27 +158,6 @@ event smtp_reply(c: connection, is_orig: bool, code: count, cmd: string,
# This continually overwrites, but we want the last reply,
# so this actually works fine.
c$smtp$last_reply = fmt("%d %s", code, msg);
if ( code != 421 && code >= 400 )
{
# Raise a notice when an SMTP error about a block list is discovered.
if ( bl_error_messages in msg )
{
local note = BL_Error_Message;
local message = fmt("%s received an error message mentioning an SMTP block list", c$id$orig_h);
# Determine if the originator's IP address is in the message.
local ips = find_ip_addresses(msg);
local text_ip = "";
if ( |ips| > 0 && to_addr(ips[0]) == c$id$orig_h )
{
note = BL_Blocked_Host;
message = fmt("%s is on an SMTP block list", c$id$orig_h);
}
NOTICE([$note=note, $conn=c, $msg=message, $sub=msg]);
}
}
}
event smtp_reply(c: connection, is_orig: bool, code: count, cmd: string,
@ -259,7 +212,7 @@ event mime_one_header(c: connection, h: mime_header_rec) &priority=5
else if ( h$name == "X-ORIGINATING-IP" )
{
local addresses = find_ip_addresses(h$name);
local addresses = find_ip_addresses(h$value);
if ( 1 in addresses )
c$smtp$x_originating_ip = to_addr(addresses[1]);
}
@ -277,7 +230,7 @@ event mime_one_header(c: connection, h: mime_header_rec) &priority=3
# If we've decided that we're done watching the received headers for
# whatever reason, we're done. Could be due to only watching until
# local addresses are seen in the received from headers.
if ( ! c?$smtp || h$name != "RECEIVED" || ! c$smtp$process_received_from)
if ( ! c?$smtp || h$name != "RECEIVED" || ! c$smtp$process_received_from )
return;
local text_ip = find_address_in_smtp_header(h$value);

198
scripts/base/protocols/ssh/main.bro
View file

@ -1,3 +1,10 @@
##! Base SSH analysis script. The heuristic to blindly determine success or
##! failure for SSH connections is implemented here. At this time, it only
##! uses the size of the data being returned from the server to make the
##! heuristic determination about success of the connection.
##! Requires that :bro:id:`use_conn_size_analyzer` is set to T! The heuristic
##! is not attempted if the connection size analyzer isn't enabled.
@load base/frameworks/notice/main
@load base/utils/site
@load base/utils/thresholds
@ -8,71 +15,49 @@ module SSH;
export {
redef enum Log::ID += { SSH };
redef enum Notice::Type += {
Login,
Password_Guessing,
Login_By_Password_Guesser,
Login_From_Interesting_Hostname,
Bytecount_Inconsistency,
};
type Info: record {
ts: time &log;
uid: string &log;
id: conn_id &log;
## Indicates if the login was heuristically guessed to be "success"
## or "failure".
status: string &log &optional;
direction: string &log &optional;
remote_location: geo_location &log &optional;
## Direction of the connection. If the client was a local host
## logging into an external host, this would be OUTBOUD. INBOUND
## would be set for the opposite situation.
# TODO: handle local-local and remote-remote better.
direction: Direction &log &optional;
## The software string given by the client.
client: string &log &optional;
## The software string given by the server.
server: string &log &optional;
## The amount of data returned from the server. This is currently
## the only measure of the success heuristic and it is logged to
## assist analysts looking at the logs to make their own determination
## about the success on a case-by-case basis.
resp_size: count &log &default=0;
## Indicate if the SSH session is done being watched.
done: bool &default=F;
};
const password_guesses_limit = 30 &redef;
# The size in bytes at which the SSH connection is presumed to be
# successful.
## The size in bytes at which the SSH connection is presumed to be
## successful.
const authentication_data_size = 5500 &redef;
# The amount of time to remember presumed non-successful logins to build
# model of a password guesser.
const guessing_timeout = 30 mins &redef;
# The set of countries for which you'd like to throw notices upon successful login
# requires Bro compiled with libGeoIP support
const watched_countries: set[string] = {"RO"} &redef;
# Strange/bad host names to originate successful SSH logins
const interesting_hostnames =
/^d?ns[0-9]*\./ |
/^smtp[0-9]*\./ |
/^mail[0-9]*\./ |
/^pop[0-9]*\./ |
/^imap[0-9]*\./ |
/^www[0-9]*\./ |
/^ftp[0-9]*\./ &redef;
# This is a table with orig subnet as the key, and subnet as the value.
const ignore_guessers: table[subnet] of subnet &redef;
# If true, we tell the event engine to not look at further data
# packets after the initial SSH handshake. Helps with performance
# (especially with large file transfers) but precludes some
# kinds of analyses (e.g., tracking connection size).
## If true, we tell the event engine to not look at further data
## packets after the initial SSH handshake. Helps with performance
## (especially with large file transfers) but precludes some
## kinds of analyses (e.g., tracking connection size).
const skip_processing_after_detection = F &redef;
# Keeps count of how many rejections a host has had
global password_rejections: table[addr] of TrackCount
&write_expire=guessing_timeout
&synchronized;
# Keeps track of hosts identified as guessing passwords
# TODO: guessing_timeout doesn't work correctly here. If a user redefs
# the variable, it won't take effect.
global password_guessers: set[addr] &read_expire=guessing_timeout+1hr &synchronized;
## This event is generated when the heuristic thinks that a login
## was successful.
global heuristic_successful_login: event(c: connection);
## This event is generated when the heuristic thinks that a login
## failed.
global heuristic_failed_login: event(c: connection);
global log_ssh: event(rec: Info);
}
@ -110,116 +95,51 @@ function check_ssh_connection(c: connection, done: bool)
# If this is still a live connection and the byte count has not
# crossed the threshold, just return and let the resheduled check happen later.
if ( !done && c$resp$size < authentication_data_size )
if ( !done && c$resp$num_bytes_ip < authentication_data_size )
return;
# Make sure the server has sent back more than 50 bytes to filter out
# hosts that are just port scanning. Nothing is ever logged if the server
# doesn't send back at least 50 bytes.
if ( c$resp$size < 50 )
if ( c$resp$num_bytes_ip < 50 )
return;
local status = "failure";
local direction = Site::is_local_addr(c$id$orig_h) ? "to" : "from";
local location: geo_location;
location = (direction == "to") ? lookup_location(c$id$resp_h) : lookup_location(c$id$orig_h);
c$ssh$direction = Site::is_local_addr(c$id$orig_h) ? OUTBOUND : INBOUND;
c$ssh$resp_size = c$resp$num_bytes_ip;
if ( done && c$resp$size < authentication_data_size )
if ( c$resp$num_bytes_ip < authentication_data_size )
{
# presumed failure
if ( c$id$orig_h !in password_rejections )
password_rejections[c$id$orig_h] = new_track_count();
# Track the number of rejections
if ( !(c$id$orig_h in ignore_guessers &&
c$id$resp_h in ignore_guessers[c$id$orig_h]) )
++password_rejections[c$id$orig_h]$n;
if ( default_check_threshold(password_rejections[c$id$orig_h]) )
{
add password_guessers[c$id$orig_h];
NOTICE([$note=Password_Guessing,
$conn=c,
$msg=fmt("SSH password guessing by %s", c$id$orig_h),
$sub=fmt("%d failed logins", password_rejections[c$id$orig_h]$n),
$n=password_rejections[c$id$orig_h]$n]);
}
}
# TODO: This is to work around a quasi-bug in Bro which occasionally
# causes the byte count to be oversized.
# Watch for Gregors work that adds an actual counter of bytes transferred.
else if ( c$resp$size < 20000000 )
c$ssh$status = "failure";
event SSH::heuristic_failed_login(c);
}
else
{
# presumed successful login
status = "success";
c$ssh$done = T;
if ( c$id$orig_h in password_rejections &&
password_rejections[c$id$orig_h]$n > password_guesses_limit &&
c$id$orig_h !in password_guessers )
{
add password_guessers[c$id$orig_h];
NOTICE([$note=Login_By_Password_Guesser,
$conn=c,
$n=password_rejections[c$id$orig_h]$n,
$msg=fmt("Successful SSH login by password guesser %s", c$id$orig_h),
$sub=fmt("%d failed logins", password_rejections[c$id$orig_h]$n)]);
}
local message = fmt("SSH login %s %s \"%s\" \"%s\" %f %f %s (triggered with %d bytes)",
direction, location$country_code, location$region, location$city,
location$latitude, location$longitude,
id_string(c$id), c$resp$size);
NOTICE([$note=Login,
$conn=c,
$msg=message,
$sub=location$country_code]);
# Check to see if this login came from an interesting hostname
when ( local hostname = lookup_addr(c$id$orig_h) )
{
if ( interesting_hostnames in hostname )
{
NOTICE([$note=Login_From_Interesting_Hostname,
$conn=c,
$msg=fmt("Strange login from %s", hostname),
$sub=hostname]);
}
}
if ( location$country_code in watched_countries )
{
}
c$ssh$status = "success";
event SSH::heuristic_successful_login(c);
}
else if ( c$resp$size >= 200000000 )
{
NOTICE([$note=Bytecount_Inconsistency,
$conn=c,
$msg="During byte counting in SSH analysis, an overly large value was seen.",
$sub=fmt("%d",c$resp$size)]);
}
c$ssh$remote_location = location;
c$ssh$status = status;
c$ssh$direction = direction;
c$ssh$resp_size = c$resp$size;
Log::write(SSH, c$ssh);
# Set the "done" flag to prevent the watching event from rescheduling
# after detection is done.
c$ssh$done;
c$ssh$done=T;
# Stop watching this connection, we don't care about it anymore.
if ( skip_processing_after_detection )
{
# Stop watching this connection, we don't care about it anymore.
skip_further_processing(c$id);
set_record_packets(c$id, F);
}
}
event SSH::heuristic_successful_login(c: connection) &priority=-5
{
Log::write(SSH, c$ssh);
}
event SSH::heuristic_failed_login(c: connection) &priority=-5
{
Log::write(SSH, c$ssh);
}
event connection_state_remove(c: connection) &priority=-5
{
if ( c?$ssh )
@ -230,7 +150,7 @@ event ssh_watcher(c: connection)
{
local id = c$id;
# don't go any further if this connection is gone already!
if ( !connection_exists(id) )
if ( ! connection_exists(id) )
return;
check_ssh_connection(c, F);
@ -248,5 +168,9 @@ event ssh_client_version(c: connection, version: string) &priority=5
{
set_session(c);
c$ssh$client = version;
schedule +15secs { ssh_watcher(c) };
# The heuristic detection for SSH relies on the ConnSize analyzer.
# Don't do the heuristics if it's disabled.
if ( use_conn_size_analyzer )
schedule +15secs { ssh_watcher(c) };
}