User Manual: Bro Output

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This section explains the contents of the various output files and reports that Bro creates.

Contents

Rotating Log Files

There are a number of ways to control the rotation of Bro's log files. Here are some examples:

# if using one log, must open append (default = truncate)

# rotate at midnight
redef log_rotate_base_time = "0:00";

# do not rotate on shutdown  (default = T)
redef RotateLogs::rotate_on_shutdown = F;

# rotate frequency
redef log_rotate_interval = 24 hr;

Alarm File

Alarm File Format

The alarm.log is a 'tagged' format that is fairly self descriptive. This is an example from the alarm.log file:

  t=1000057981.940712 no=AddressScan na=NOTICE_ALARM_ALWAYS sa=10.1.1.1 sp=2222/tcp da=10.2.2.2 dp=3333/tcp msg=10.1.1.1\ has\ scanned\ 2000\ hosts\ (3333/tcp) tag=@42

Here the tags indicate the following:

  • t: time
  • no: notice
  • na: notice action
  • sa: source address
  • sp: source port
  • da: destination address
  • dp: destination port
  • msg: message (in this case a host has scanned 20 hosts)
  • tag: identifier to match this to lines in notice.log and conn.log:

The alarm file format is designed to be easy to parse and interpret by programs, not humans.

Sample Alarm File Contents

NOTE: the examples in this section still use the old log format. This needs to be updated

Bro generates a number of types of alarms, such as suspicious connection attempts directed at your systems (address scanning), port scans, and attempts to gain access to user accounts. We describe some of these in more detail here.

Vulnerability scans directed against systems

The first category of suspicious connection attempts that Bro identifies and reports is vulnerability scans directed against systems. Instead of burdening you with every vulnerability scan (no matter how tiny) against systems that occurs, it reports only scans that occur at or above its threshold in terms of a specified size, such as the number of vulnerability scan attempts per second. The following entry indicates that IP address 66.243.211.244 has scanned 10000 of your systems on tcp port 445, the port used by newer Windows systems such as Windows 2000, XP and Server 2003 for share access:

Nov 16 06:30:49 AddressScan 66.243.211.244 has scanned 10000 hosts (445/tcp)

Important note: If the source of a scan is an IP address within your own network, the probability that this system is infected or has been taken over by an attacker is very high.

At the bottom portion of each Bro report summaries of scan activity also will appear for your convenience (see the bottom part of Figure 1). Scan summaries look like the following:

Nov 16  8 01:30:11 ScanSummary 194.201.88.100 scanned a total of 145 hosts

Port scanning

Port scanning means that a system has targeted one system, connecting to one port, then another, until it has scanned a whole range of ports. In the following example a system with an IP address of 218.204.91.85 has scanned 50 ports of a system named diblys.dhcp within an internal network:

Nov 16 06:30:50 PortScan 218.204.91.85 has scanned 50 ports of siblys.dhcp

An address dropped entry is likely to appear shortly after a port scan is reported. In the following entry, the system with an IP address of 218.204.91.85 was systematically probing low ports, that is, ports in the range from 0 to 1023, on sibyls.dhcp:

Nov 16 06:30:52 AddressDropped low port trolling 218.204.91.85 403/tcp

Connection attempts

Bro finds attacks against user accounts, such as password guessing attempts. When it does, it reports them as follows:

(Need example here)

Weird events

Bro labels unusual or exceptional events as weird. Weird events include a wide range of events, including malformed connections, attacker's attempts to confuse or evade being detected, malfunctioning hardware, or misconfigured systems or network devices such as routers. Some weird events could be the result of an attack; others are just anomalies. The better you know your own systems and networks, the more likely you will be to correctly determine whether or not weird events compromise an attack. Weird events are divided into three categories:

  1. Weird connections that are not formed in accordance with protocol conventions such as the way the tcp protocol should work
  2. Weird flows in which data is being sent between two systems, but no specific connection between them can be identified, and
  3. Weird network behavior that cannot be associated with any particular system.

The following entry shows a weird connection in which packets are being sent between systems in what appears to be an ongoing ftp session, but Bro has not identified any initial connection attempt (i.e., there is an ack above a hole):

Nov 16 06:30:58 WeirdActivity window/50406 > klecker.debian.org/ftp ack above a hole

The next entry (below) shows another weird traffic pattern in which eqvaadvip1.doubleclick.net has sent a flood of FIN packets, packets that tell the other system in a connection to terminate the connection, to bcig-8 within the network that Bro protects.

Nov 16 06:32:09 WeirdActivity bcig-8/2044 > eqvaadvip1.doubleclick.net/http: FIN_storm

Here's another one --- in this case a system with an IP address of 222.64.93.208 has sent a flood of packets that have both the SYN and the ACK flags set, something that should normally happen only once in a TCP session. nsx is the destination system.

Nov 16 06:30:58 WeirdActivity 222.64.93.208/1115 > nsx/dns: repeated_SYN_with_ack

Packets sent over networks are often broken up (or fragmented) for various reasons. Fragmented packets are not necessarily a sign of an attack, but large fragments can indicate suspicious activity such as attempts to cause denial of service. In the following example Bro has identified a very large packet fragment sent by p508c7fc5.dip.t-dialin.net to an internal system with an IP address of 131.243.3.162:

Nov 16 06:30:50 WeirdActivity p508c7fc5.dip.t-dialin.net -> 131.243.3.162: excessively_large_fragment

Sometimes attackers attempt to evade being detected by sending malformed packets to the system they are attacking. The receiving system cannot process them, so it informs the sending (attacking system) accordingly, asking it to resend them. The sending system may now send packets that constitute an attack. Some intrusion detection systems (but not Bro) ignore what is resent because in theory it is unnecessary to reanalyze what has already been sent. Bro detects this kind of retransmission inconsistency (rexmit inconsistency) and reports it. The following example shows that there has been retransmission inconsistency in packets sent by a system at IP address 131.243.223.212 to origin2.microsoft.com:

Nov 16 06:30:59 RetransmissionInconsistency 131.243.223.212/2270 > origin2.microsoft.com/http @/ rexmit inconsistency (HTTP/1.1 200 OK^M^JDate: Tue, 16 Nov 2004

Connection Summary File

See the Connection Summary section in the Reference Manual for a description of the conn.log files.

Analyzer-specific Files

A number of analyzers such as HTTP and FTP generate their own log files. These files are fairly self explanatory.

coming soon: sample http.log, ftp.log, etc

Tracefiles

Bro can be configured to output captured packets that look to be part of suspicious sessions. These files are in tcpdump format.

Bro Summary Reports

may be out of date. }

Bro reports are generated using the site-report.pl script, which is typically run as a nightly cron job.

A daily report is created that covers three sets of information:

  • Incident information
  • Operational status of Bro
  • General network traffic information

The reports will be mailed to the email addresses specified during Bro installation. These email addresses can be changed by re-running the bro_config script or by editing $BROHOME/etc/bro.cfg directly.

The report is divided into three parts, the summary, incidents, and scans. The summary includes a rollup of incident information, Bro operational statistics, and network information. The incidents section has details for each Bro alarm. The scans section gives details about scans that Bro detected.

Parts of a Report

The header gives some basic information about the report. Site name is determined by the "Site name for reports" that was given during the installation and configuration process.

Start time and interval of the report are also entered during the configuration process.

This section give a numeric summary of the events that have happened in the reporting period.

Incidents shows the number of incidents that are recorded in the report period. An incident is any occurrence that is deemed worth investigating. An incident is formed by the triggering of one or more alarms.

Scanning Hosts are the number of specific IP addresses that have been detected scanning either into or out from the site. A scan can be a:

  • port scan: scanning several ports of a single host.
  • network scan: scanning several hosts for open ports.
  • signature scan: attacking multiple hosts with a specific vulnerability attack (signature).
  • targeted attack: launching multiple signatures against a single host.
  • password scan: attempts to guess passwords on telnet terminals.

A successful scan is when:

  • the bytes sent by a single probe of a scan against a host or several hosts are more than three deviations away from the standard deviation of the rest of scan. In essence, where the bytes transferred on one connection is different than the rest of the scan other connections involved in the scan,
  • a separate connection back to the attacker host is detected from the local network,
  • the number of bytes sent back from the targeted victim host to the offender during a scan connection exceeds 20480.


Signature Summary shows the total number of alarms triggered by signatures during the report period and the number of those that are unique. These numbers do not include alarms triggered by embedded Bro rules. See Understand What Triggered the Alarm(s).

This is a list of all signatures that were triggered during the report period.

Caution.png Note: This section does not include alarms triggered by embedded Bro rules.

Count is the number of times the signature was seen.

Unique Sources is the number of unique ip addresses that used the specific signature as an attack.

Unique Dests is the number of unique ip addresses that were attacked by the particular signature.

Unique Pairs are the number of unique source/dest ip address pairs where the source used the signature to attack the destination.

Legend This is the legend for reading the connections portions of the each incident. It is shown once on each report at the top of the Incidents section.

Incident number Each incident listed in the Bro report is assigned a unique, sequential, identification number prefixed with the organization identifier. This number is unique for all incidents, not just to the daily reports.

Remote and Local hosts The Remote and Local hosts are identified by both ip address and hostname. The local hosts are those that are in local subnets as determined during Bro configuration. It is important to note that remote host does not infer attack host. Attacks can come from local hosts (indicating an inside hacker or a compromised host).

Alarms The network event(s) that Bro detects and identifies as possible attacks. There are two general types of alarms, those triggered by signatures and those triggered by Bro rules. All alarms will include the date/time of the attack, the direction of the attack, and the ports involved. A SensitiveSignature will include the signature code and payload to help evaluate what triggered the alarm. Embedded Bro rules will include the payload and a session number which can be used for further investigation in the logs.

Connections A list of the first 25 connections after the first alarm is triggered that are attempted between the attacking and victim host. This tabulation of connections can be used to see if connections were accepted by the victim host, the amount of bytes transferred in both directions, the timing between the connections, and the ports involved.

This is a summary of the ip addresses involved in successful scans, the type of scans, and the attacks used by the scanners.

This section gives a overview of the most prominent connections that have occurred during the report period, as shown by way of five tables.

Site-wide connection statistics The number of successful and unsuccessful connections and the ratio between the two.

Top 20 Sources Hosts that have initiated the most connections.

Top 20 Destinations Hosts that have accepted connections.

Top 20 Local E-mail Servers The most active E-mail servers.

Top 20 Services The services, as determined by port number, that have been involved in connections.

This section gives a summary of the ip address address pairs that have transferred the most bytes during the report period.

Annotated Example Report:

Site Report for ORG_NAME 
from 2004/11/03 00:00:00 to 2004/11/04 00:00:00
generated on Sat Nov 13 12:02:48 2004

Since this report is simple and only includes two incidents, the summary is rather uninteresting. A glance at this summary would reveal a rather "slow" day (for which you should be thankful).

========================================================================
Summary
========================================================================

 Incidents               2
 Scanning Hosts
   Successful            8
   Unsuccessful          15
 Signature Summary
   Total signatures          2
   Unique signatures         2
   Unique sources            2
   Unique destinations       2
   Unique source/dest pairs  1

Since the same to ip addresses were involved in both signature attacks, there is only one unique source/dest pair.

========================================================================
Signature Distributions
========================================================================
                                      Unique      Unique    Unique
 Signature ID               Count     Sources     Dests      Pairs
 ------------------------  --------  ---------  ---------  --------
 bro-687-5                 1          1          1          1
 bro-144-3                 1          1          1          1
========================================================================
Incident Details
========================================================================

The following legend appears once in every report at the top of the "Incidents" section.

    # legend for connection type #
                 ------------------------------
        C Connection Status
          # number corresponds to alarm triggered by the connection
          * successful connection, otherwise unsuccessful.
        I Initiatator of Connection
          > connection initiated by remote host
          < connection initiated by local host
------------------------------------------------------------------------
Incident      ORG_NAME-000004524
------------------------------------------------------------------------

The host domain name "org_name.org" will normally be replaced by the local domain name. The IP addresses in this example have been synthesized from an imaginary range outside of the octal range. (We realize these ip addresses cannot exist). In this example the ip ranges 124.333.0.0/24 and 132.257.0.0/24 are considered the local subnets.

Remote Host: 84.136.338.21   p54877614.dip.hacker.net
Local Host: 124.333.183.162 pooroljoe.dhcp.org_name.org

This attacker was successful in using an SQL attack and then downloaded a "tool" using TFTP. Both of these were detected and created the following alarms.

Alarm: SensitiveSignature
 1    bro-687-5: MS-SQL xp_cmdshell - program execution
      7/29 12:43:31                  84.136.338.21 -> 124.333.183.62
                                           566/tcp -> 1433/tcp
      signature code:
      signature bro-687-5 {
        ip-proto == tcp
        dst-port == 1433
        event "MS-SQL xp_cmdshell - program execution"
        tcp-state established,originator
        payload /.*[xX]\x00[pP]\x00_\x00[cC]\x00[mM]\x00[dD]\x00[sS]
        \x00[hH]\x00[eE]\x00[lL]\x00[lL]\x00/
      }
      payload: xp_cmdshell 'echo.> c:\\temp\\bcp.cmd'
Alarm: SensitiveSignature
 2    bro-1444-3: TFTP Get
      7/29 12:43:31                  84.136.338.21 -> 124.333.183.62
                                          2318/upd -> 69/udp
      signature code:
      signature bro-1444-3 {
          ip-proto == udp
          dst-port == 69
          event "TFTP Get"
          payload /\x00\x01/
          }
      payload: Runtime.exe

Looking at the "C" column below, the alarms are signified by "1" and "2", both occuring at 12:43:31. Since the attacks take place within one second, this is probably an automated attack. The remote host continues to connect to the victim host, using a different port each time to avoid detection. The large transfers from the local host to the remote host, subsequent to the alarmed attacks, signifies that the attack is probably successful.

Connections (only first 25 after first alarm are listed)
-----------
                time     byte   remote        local   byte
date   time   duration transfer  port  C   I   port transfer  protocol
----- -------- -------- -------- ------ ------ ----- -------- ----------
07/29 12:43:31        ?     566 b  4634 1   >  1433      467 b tcp/MSSQL
07/29 12:43:31        0         ?  2318 2  <     69       20 b udp/tftp
07/29 12:43:32    265.7       4 b  4638 *  <   2318      3.0kb udp
07/29 12:48:56        ?         ?  4640     >  2362          ? tcp
07/29 12:50:05        ?    11.4kb  4639 *  <   3333      8.6kb tcp
07/29 12:53:00        0         ?  4684 *   >  2362          ? tcp
07/29 12:53:07        ?         ?  4685 *   >  2362          ? tcp
07/29 12:53:59        ?         ?  4689 *   >  2362          ? tcp
07/29 12:54:14      6.1         0  4693 *  <   2380     94.2kb tcp
07/29 12:54:21       .5      50 b  4694     >  2381          0 tcp
07/29 12:54:23       .7         ?  4695    <   2382          0 tcp
07/29 12:54:25       .5      51 b  4696 *   >  2383          0 tcp
07/29 12:54:27       .5      61 b  4697 *   >  2384          0 tcp
07/29 12:54:28       .7      39 b  4698     >  2385          0 tcp
07/29 12:54:31       .5      41 b  4699 *   >  2386          0 tcp
07/29 12:54:33      1.2    4.9 kb  4700     >  2387          0 tcp
07/29 12:54:35     12.8  195.0 kb  4701 *  <   2388          0 tcp
07/29 12:54:53       .2         ?  4703    <   2390          0 tcp
07/29 12:54:54       .5      37 b  4704     >  2391          0 tcp
07/29 12:54:56      3.4      23 b  4705 *   >  2392          0 tcp
07/29 12:55:04     21.4  308.7 kb  4706     >  2393          0 tcp
07/29 12:55:27     50.7         ?  4707     >  2394          ? tcp
07/29 12:59:23        ?         ?  4775     >  1433          ? tcp
07/29 12:59:25        ?         ?  4774 *   >  3333          ? tcp

The next Incident demonstrates alarms triggered by embedded rules, rather than signatures.

------------------------------------------------------------------------
Incident      ORG_NAME-000004525
--------------------------------
Remote Host:  80.143.378.186     p508FB2BA.dip.t-dialin.net
Local Host:  128.333.181.191      lemonade.lbl.gov

Since these alarms are triggered in the HTTP protocol, the actual trigger rules are found in the file bro/policy/http.bro.

Alarm: HTTP_SensitiveURI
      11/13 11:36:05                80.143.378.186 -> 128.333.181.191
                                          1560/tcp -> 80/tcp
      session: %4672
      payload: GET http://cn.edit.vip.cnb.yahoo.com/config/login?.redir
               _from=PROFILES
Alarm: HTTP_SensitiveURI
      11/13 11:53:54                80.143.378.186 -> 128.333.181.191
                                          2434/tcp -> 80/tcp
      session:%7386
      payload: GET http://l10.login.scd.yahoo.com/config/login?.redir_f
               rom=PROFILES?&

In the connections shown below, all connections are from the remote host to the local host, with no successful connections back. Also the payload above is seeking yahoo.com. Hence the likelihood is that this is not an attack.

Connections (only first 25 after alarm are listed)
-----------
                time     byte   remote        local   byte
date   time   duration transfer  port  C   I   port transfer  protocol
----- -------- -------- -------- ------ ------ ----- -------- ----------
11/13 11:36:05 1.109227      297   1560 *    >    80     1531       http
11/13 11:36:06        ?        ?   1560      >    80        ?       http
11/13 11:41:51 0.843209      301   3175 *    >    80     1533       http
11/13 11:41:52        ?        ?   3175      >    80        ?       http
11/13 11:47:37 2.562365      281   4701 *    >    80     1382       http
11/13 11:47:39        ?        ?   4701      >    80        ?       http
11/13 11:53:53 0.694131      293   2434 *    >    80     1529       http
11/13 11:53:54        ?        ?   2434      >    80        ?       http
11/13 11:59:23 0.685181      301   3975 *    >    80     1529       http
11/13 11:59:23        ?        ?   3975      >    80        ?       http
11/13 12:04:53 1.054925      289   1700 *    >    80     1527       http
11/13 12:04:54        ?        ?   1700      >    80        ?       http
11/13 12:11:56 2.579652      283   3442 *    >    80     1523       http
11/13 12:11:59        ?        ?   3442      >    80        ?       http
11/13 12:18:08 1.046188      289   1083 *    >    80     1531       http
11/13 13:14:42        ?        ?   3282      >    80        ?       http
11/13 13:16:46        ?        ?   4802      >    80        ?       http
11/13 13:19:04 1.731771        0   2764 *    >    80        0       http
11/13 13:19:07        ?        ?   2764      >    80        ?       http
11/13 13:20:42 0.994114      289   4142 *    >    80     1527       http
11/13 13:20:43        ?        ?   4142      >    80        ?       http
11/13 13:22:37 1.122448      292   1732 *    >    80     1523       http
11/13 13:22:38        ?        ?   1732      >    80        ?       http
11/13 13:24:40 1.042112      289   3179 *    >    80     1531       http
11/13 13:24:41        ?        ?   3179      >    80        ?       http
========================================================================
Scans (only first 100 shown)
========================================================================

The scans show below are considered "successful". Four interesting scans shown below are the ones originating from the 124.333 and 132.257 domains, since they are local domains. These should be investigated. The attack against 132.257.85.96 might also be investigated further. With each report, a review of the attacks will give an understanding of what types of scans are becoming "popular".

Scanning IP      Victim IP       Attack
132.257.70.234   multiple        bro-1344-5
132.257.52.64    multiple        bro-1367-5
63.251.3.51      multiple        bro-2570-6
124.333.181.191  multiple        bro-1599-7
210.313.36.53    132.257.85.96   >1000 port scan
211.300.24.151   132.257.85.96   >1000 port scan
124.333.95.0     62.214.34.30    >250 port scan
172.278.206.135  multiple       (3128/tcp)
========================================================================
Connection Log Summary
========================================================================

The connection log summary gives a general idea of what hosts are most active. The analyst may want to become familiar with any new hosts that appear on the next three lists and services that appear or radically change position on the fourth list

Site-wide connection statistics
   Successful:   4498748
   Unsuccessful: 35941140
   Ratio: 1:7.989
Top 20 Sources
               Host                      IP         Bytes   Conn. Count
 --------------------------------  ---------------  ------  -----------
                 ns1.org_name.org  124.333.34.186    3.7 G       683948
                 ns2.org_name.org  132.257.64.2      165 M       231245
            lemonade.org_name.org  124.333.181.191    88 M       217781
                 nsx.org_name.org  132.257.64.3      371 M       200935
              cinnamon.mining.com  207.5.380.138     4.5 M       103011
      node2.lbnl.nodes.planet.org  198.328.56.12     106 M        75725
      node1.lbnl.nodes.planet.org  198.328.56.11      85 M        73719
     microscope.dhcp.org_name.org  132.257.19.79      61 M        54024
                                   169.299.224.1     2.3 M        40348
               uhuru.org_name.org  132.257.10.97     423 M        39847
                                   132.257.77.246     13 M        29496
           googledev.org_name.org  124.333.41.57      13 M        24930
                                   64.46.248.43       60 M        19785
 ...16-141.sfo4.dsl.contactor.net  66.292.16.141     6.2 M        19048
                     rock.es.net  198.128.2.83      2.8 G        18459
            perry.Geo.college.EDU  124.32.349.11     1.7 M        17326
              google.org_name.org  124.333.41.70     8.5 M        15508
            egspd42212.search.com  65.264.38.212     3.1 M        15138
      hmb-330-042.MSE.college.EDU  124.32.349.20     222 M        14865
         1rodan.dhcp.org_name.org  132.257.19.170    7.7 M        11873
Top 20 Destinations
               Host                      IP         Bytes   Conn. Count
 --------------------------------  ---------------  ------  -----------
                 nsx.org_name.org  132.257.64.3       14 G      1571638
                 ns1.org_name.org  124.333.34.186    1.6 G       264976
                 ns2.org_name.org  132.257.64.2       80 M       218740
            lemonade.org_name.org  124.333.181.191   2.6 G       176788
                CS.university.EDU  128.312.136.10     10 M        81622
                g.old-servers.net  192.42.293.30      11 G        71407
         engram.CS.university.EDU  128.312.136.12    7.5 M        61309
              aulvs.realthing.com  207.288.24.156    792 M        50493
                  ns1.college.EDU  124.32.349.9      995 M        39977
                 rohan.superc.gov  128.550.6.34      4.7 G        32883
           sportsmed.starship.com  199.281.132.79     17 M        32152
                     ns2.yoho.com  66.263.169.170    2.1 G        24361
               uhuru.org_name.org  132.257.10.97      58 M        19785
                     g3.NSDDD.COM  192.342.93.32     488 M        19734
                  w4.org_name.org  124.333.7.51      447 M        19334
                E.TOP-SERVERS.NET  192.303.230.10    195 M        19066
              mantis.org_name.org  124.333.7.39      395 M        18811
             postala.org_name.org  124.333.41.61     8.0 M        17283
               vista.org_name.org  132.257.48.146    488 M        15961
              calmail.college.EDU  128.32.349.103     73 M        15154
Top 20 Local Email Senders
                 Hostname                        IP          Conn.
Count
 ----------------------------------------  ---------------  -----------
                        mta1.org_name.org  124.333.41.24           3869
                     postala.org_name.org  124.333.41.61           2850
                          ci.org_name.org  132.257.192.220          868
                     postal2.org_name.org  132.257.248.26           376
                          ee.org_name.org  132.257.1.10             173
                        math.org_name.org  124.333.7.22             131
                        rod2.org_name.org  132.257.112.183          121
                        gigo.org_name.org  124.333.2.54             110
                         mh1.org_name.org  124.333.7.48              82
                         stm.org_name.org  132.257.16.51             81
Top 20 Services
 Service        Conn. Count  % of Total   Bytes In  Bytes Out
 ------------  ------------  ----------  ---------  ---------
 dns                3378522       75.10       30 G       11 G
 http                902573       20.06       18 G       11 G
 other                92913        2.07       14 G      249 G
 smtp                 35942        0.80      458 M      196 M
 https                33848        0.75      2.3 G      179 M
 ssh                  25515        0.57      977 M      1.0 G
 netbios-ssn          11004        0.24       65 M      9.5 M
 pop-3                 5494        0.12       58 M      3.6 M
 ftp-data              4495        0.10       37 G       34 G
 ldap                  3549        0.08      740 K      2.0 M
 ftp                   1061        0.02      1.3 M      873 K
 ident                  970        0.02      29602       9039
 printer                834        0.02        837       9176
 time                   645        0.01       2416        166
 imap4                  636        0.01       28 M       47 M
 nntp                   308        0.01      355 M      1.5 M
 pm_getport             238        0.01      13328       6664
 telnet                 164        0.00      469 K       7850
 ntp                     26        0.00       1344       1392
 X11                      6        0.00      652 K      64280
========================================================================
Byte Transfer Pairs
========================================================================

Once again, this summary gives a general idea of what hosts are most active. Radical changes to this list may indicate malicious activity.

Hot Report - Top 20
                                   Local      Remote     Conn.
 Local Host       Remote Host      Bytes      Bytes      Count
---------------  ---------------  ---------  ---------  ---------
124.333.28.60    128.265.128.131      123 G     5327 K  3930
124.333.28.60    128.265.128.132      123 G     5159 K  3927
132.257.64.3     198.328.2.83        2855 M     11.9 G  15097
124.333.34.186   192.342.93.30       2958 M     10.7 G  40033
132.257.64.3     61.283.32.172       7469 M      10393  11
124.333.41.57    128.256.6.34        12.0 M     4490 M  22360
124.333.181.191  81.257.197.163      1350 M     4430 M  3341
132.257.64.3     130.262.101.6        276 M     2200 M  13064
124.333.34.186   66.263.169.170       389 M     2095 M  17919
132.257.195.68   140.267.28.48       91.3 M     2029 M  6275
132.257.212.232  151.293.199.65       39155     1994 M  24
124.333.41.61    206.290.82.18         3401     1853 M  22
132.257.64.3     61.278.72.30        1798 M          7  1
124.333.181.191  61.263.209.246      16.8 M     1676 M  113
132.257.64.3     261.232.163.3       1544 M      24069  9
132.257.64.3     61.273.210.110      1517 M       4140  7
124.333.34.186   128.342.121.70      1351 M      222 M  14861
132.257.64.3     258.14.200.58       1350 M      24075  14
132.257.64.3     222.330.100.28      1219 M       4077  7
132.257.64.3     210.261.41.131      1162 M         25  3

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Overview of Bro | Requirements | Installation and Configuration

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Intrusion Prevention Using Bro | Performance Tuning | Bulk Traces and Off-line Analysis

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