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NEWS
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This document summarizes the most important changes in the current Bro
release. For an exhaustive list of changes, see the ``CHANGES`` file
(note that submodules, such as BroControl and Broccoli, come with
their own ``CHANGES``.)
Bro 2.6 (in progress)
=====================
New Functionality
-----------------
- Bro has switched to using the new Broker library for all its
communication. Broker's API has been completely redesigned (compared
to the version in 2.5), and much of its implementation has been
redone. There's a new script-level "broker" framework that
supersedes the old "communication" framework, which is now
depracated. The "cluster" and "control" frameworks have been ported
to Broker; same for BroControl. For more about the new Broker
framework, see doc/frameworks/broker.rst (there's also guide there
for porting existing Bro scripts to Broker). For more about Broker
itself, including its API for external applications, see
aux/broker/doc.
TODO: Replace documentation paths with URLs once these are available
online.
When using BroControl, the meaning of proxies has changed with
Broker. If you are upgrading and have configured more than one proxy
currenty, we recommend going back down to a single proxy node now.
Unless you are using custom scripts doing significant data
distribution themselves through the new cluster framework, that
should be fine.
- Bro now has new "is" and "as" script operators for dynamic
type-checking and casting.
- "v as T" casts a value v into a value of type T, assuming that's
possible (if not, it triggers a runtime error).
- "v is T" returns a boolean indicating whether value v can be
casted into type T (i.e., if true then "v as T" will succeed).
This casting supports three cases currently: (1) a value of
declared type "any" can be casted to its actual underlying type;
(2) Broker values can be casted to their corresponding script
types; and (3) all values can be casted to their declared types
(i.e., a no-op).
Example for "any":
# cat a.bro
function check(a: any)
{
local s: string = "default";
if ( a is string )
s = (a as string);
print fmt("s=%s", s);
}
event bro_init()
{
check("Foo");
check(1);
}
# bro a.bro
s=Foo
s=default
- The existing "switch" got extended to now also support switching by
type rather than value. The new syntax supports two type-based versions
of "case":
- "case type T: ...": Take branch if operand can be casted to type T.
- "case type T as x: ... ": Take branch if operand can be casted
to type T, and make the casted value available through ID "x".
Multiple types can be listed per branch, separated by commas.
However, one cannot mix cases with expressions and types inside a
single switch statement.
Example:
function switch_one(v: any)
{
switch (v) {
case type string:
print "It's a string!";
break;
case type count as c:
print "It's a count!", c;
break;
case type bool, type addr:
print "It's a bool or address!";
break;
default:
print "Something else!";
break;
}
}
- Bro now comes with a new "configuration framework" that allows
updating script options dynamically at runtime. This functionality
consists of three larger pieces working together:
- Option variables: The new "option" keyword allows variables to be
declared as runtime options. Such variables cannot be changed
using normal assignments. Instead, they can be changed using the
new function Option::set.
It is possible to "subscribe" to an option through
Option::set_change_handler, which will trigger a handler callback
when an option changes. Change handlers can optionally modify
values before they are applied by returning the desired value, or
reject updates by returning the old value. Priorities can be
specified if there are several handlers for one option.
Example script::
option testbool: bool = T;
function option_changed(ID: string, new_value: bool): bool
{
print fmt("Value of %s changed from %s to %s", ID, testbool, new_value);
return new_value;
}
event bro_init()
{
print "Old value", testbool;
Option::set_change_handler("testbool", option_changed);
Option::set("testbool", F);
print "New value", testbool;
}
- Script-level configuration framework: The new script framework
base/framework/config facilitates reading in new option values
from external files at runtime. The format for these files looks
like this:
[option name][tab/spaces][new variable value]
Configuration files to read can be specified by adding them to
Config::config_files.
Usage example::
redef Config::config_files += { "/path/to/config.dat" };
module TestConfig;
export {
option testbool: bool = F;
}
The specified file will now be monitored continuously for changes, so
that writing "testbool T" into /path/to/config.dat will
automatically update the option's value accordingly.
The configuration framework creates a config.log that shows all
value changes that took place.
- Config reader: Internally, the configuration framework uses a new
type of input reader to read such configuration files into Bro.
The reader uses the option name to look up the type that variable
has, converts the read value to the correct type, and then updates
the option's value. Example script use::
type Idx: record {
option_name: string;
};
type Val: record {
option_val: string;
};
global currconfig: table[string] of string = table();
event InputConfig::new_value(name: string, source: string, id: string, value: any)
{
print id, value;
}
event bro_init()
{
Input::add_table([$reader=Input::READER_CONFIG, $source="../configfile", $name="configuration", $idx=Idx, $val=Val, $destination=currconfig, $want_record=F]);
}
- Support for OCSP and Signed Certificate Timestamp. This adds the
following events and BIFs:
- Events: ocsp_request, ocsp_request_certificate,
ocsp_response_status, ocsp_response_bytes
ocsp_response_certificate ocsp_extension
x509_ocsp_ext_signed_certificate_timestamp
ssl_extension_signed_certificate_timestamp
- Functions: sct_verify, x509_subject_name_hash,
x509_issuer_name_hash x509_spki_hash
- The SSL scripts provide a new hook "ssl_finishing(c: connection)"
to trigger actions after the handshake has concluded.
- New functionality has been added to the TLS parser, adding several
events. These events mostly extract information from the server and client
key exchange messages. The new events are:
ssl_ecdh_server_params, ssl_dh_server_params, ssl_server_signature,
ssl_ecdh_client_params, ssl_dh_client_params, ssl_rsa_client_pms
Since ssl_ecdh_server_params contains more information than the old
ssl_server_curve event, ssl_server_curve is now marked as deprecated.
- Functions for retrieving files by their ID have been added:
Files::file_exists, Files::lookup_File
- New functions in the logging API: Log::get_filter_names, Log::enable_stream
- HTTP now recognizes and skips upgraded/websocket connections. A new event,
http_connection_upgrade, is raised in such cases.
- Added a MOUNT3 protocol parser
- This is not enabled by default (no ports are registered and no
DPD signatures exist, so no connections will end up attaching the
new Mount analyzer). If it were to be activated by users, the
following events are available: mount_proc_null, mount_proc_mnt,
mount_proc_umnt, mount_proc_umnt_all, mount_proc_not_implemented,
mount_reply_status.
- Added new NFS events: nfs_proc_symlink, nfs_proc_link, nfs_proc_sattr
- Added new SMB events: smb1_transaction_secondary_request,
smb1_transaction2_secondary_request, smb1_transaction_response
Changed Functionality
---------------------
- ALl communication is now handled through Broker, requiring changes
to existing scripts to port them over to the new API. The Broker
framework documentation comes with a porting guide.
- The DHCP analyzer and its script-layer interface have been rewritten.
- Supports more DHCP options than before.
- The DHCP log now represents DHCP sessions based on transaction ID
and works on Bro cluster deployments.
- Removed the policy/protocols/dhcp/known-devices-and-hostnames.bro
script since it's generally less relevant now with the updated log.
- Removed policy/misc/known-devices.bro script and thus
known_devices.log will no longer be created.
- Removed the base/protocols/dhcp/utils.bro script and thus the
'reverse_ip' function.
- Replaced all DHCP events with the single 'dhcp_message' event.
The list of removed events includes:
- dhcp_discover
- dhcp_offer
- dhcp_request
- dhcp_decline
- dhcp_ack
- dhcp_nak
- dhcp_release
- dhcp_inform
- The --with-binpac= configure option has changed to mean "path
to the binpac executable" instead of "path to binpac installation root".
- The MIME types used to identify X.509 certificates in SSL
connections changed from "application/pkix-cert" to
"application/x-x509-user-cert" for host certificates and
"application/x-x509-ca-cert" for CA certificates.
- With the new ssl_ecdh_server_params event, the ssl_server_curve
event is considered deprecated and will be removed in a future
version of Bro.
- The Socks analyzer no longer logs passwords by default. This
brings its behavior in line with the FTP/HTTP analyzers which also
do not log passwords by default.
To restore the previous behavior and log Socks passwords, use:
redef SOCKS::default_capture_password = T;
- The DNS base scripts no longer generate some noisy and annoying
weirds (dns_unmatched_msg, dns_unmatched_msg_quantity, dns_unmatched_reply)
- The 'tunnel_parents' field of conn.log is now marked &optional, so, for
the default configuration of logs, this field will show "-" instead of
"(empty)" for connections that lack any tunelling.
- SMB event argument changes:
- smb1_transaction_request now has two additional arguments, "parameters"
and "data" strings
- smb1_transaction2_request now has an additional "args" record argument
- SSL event argument changes:
- event ssl_server_signature now has an additional argument
"signature_and_hashalgorithm".
- The "dnp3_header_block" event no longer has the "start" parameter
Removed Functionality
---------------------
- We no longer maintain any Bro plugins as part of the Bro
distribution. Most of the plugins that used be in aux/plugins have
been moved over to use the Bro Package Manager instead. See
https://github.com/bro/packages for a list of Bro packages currently
available.
- BroControl: The option 'IPv6Comm' and 'ZoneID' options are no longer
available (though Broker should be able to handle IPv6
automatically).
Deprecated Functionality
------------------------
- The old communication system is now deprecated and scheduled for
removal with the next Bro release. This includes the "communication"
framework, the &sychronized attributes, and the existing
communication-related BiFs. Use Broker instead.
- The infrastructure for serializing Bro values into a binary
representation is now deprecated and scheduled for removal with the
next Bro release. This includes the &persistent attribute, as well
as BiFs like send_id(). Use Broker data stores and the new
configuration framework instead.
- BroControl: The 'update' command is deprecated and scheduled for
removal with the next Bro release. Bro's new configuration framework
is taking its place.
Bro 2.5.1
=========
New Functionality
-----------------
- Bro now includes bifs for rename, unlink, and rmdir.
- Bro now includes events for two extensions used by TLS 1.3:
ssl_extension_supported_versions and ssl_extension_psk_key_exchange_modes
- Bro now includes hooks that can be used to interact with log processing
on the C++ level.
- Bro now supports ERSPAN. Currently this ignores the ethernet header that is
carried over the tunnel; if a MAC is logged currently only the outer MAC
is returned.
- Added a new BroControl option CrashExpireInterval to enable
"broctl cron" to remove crash directories that are older than the
specified number of days (the default value is 0, which means crash
directories never expire).
- Added a new BroControl option MailReceivingPackets to control
whether or not "broctl cron" will mail a warning when it notices
that no packets were seen on an interface.
- There is a new broctl command-line option "--version" which outputs
the BroControl version.
Changed Functionality
---------------------
- The input framework's Ascii reader is now more resilient. If an input
is marked to reread a file when it changes and the file didn't exist
during a check Bro would stop watching the file in previous versions.
The same could happen with bad data in a line of a file. These
situations do not cause Bro to stop watching input files anymore. The
old behavior is available through settings in the Ascii reader.
- The RADIUS scripts have been reworked. Requests are now logged even if
there is no response. The new framed_addr field in the log indicates
if the radius server is hinting at an address for the client. The ttl
field indicates how quickly the server is replying to the network access
server.
- With the introduction of the Bro package manager, the Bro plugin repository
is considered deprecated. The af_packet, postgresql, and tcprs plugins have
already been removed and are available via bro-pkg.
Bro 2.5
=======
New Dependencies
----------------
- Bro now requires a compiler with C++11 support for building the
source code.
- Bro now requires Python instead of Perl to compile the source code.
- When enabling Broker (which is disabled by default), Bro now requires
version 0.14 of the C++ Actor Framework.
New Functionality
-----------------
- SMB analyzer. This is the rewrite that has been in development for
several years. The scripts are currently not loaded by default and
must be loaded manually by loading policy/protocols/smb. The next
release will load the smb scripts by default.
- Implements SMB1+2.
- Fully integrated with the file analysis framework so that files
transferred over SMB can be analyzed.
- Includes GSSAPI and NTLM analyzer and reimplements the DCE-RPC
analyzer.
- New logs: smb_cmd.log, smb_files.log, smb_mapping.log, ntlm.log,
and dce_rpc.log
- Not every possible SMB command or functionality is implemented, but
generally, file handling should work whenever files are transferred.
Please speak up on the mailing list if there is an obvious oversight.
- Bro now includes the NetControl framework. The framework allows for easy
interaction of Bro with hard- and software switches, firewalls, etc.
New log files: netcontrol.log, netcontrol_catch_release.log,
netcontrol_drop.log, and netcontrol_shunt.log.
- Bro now includes the OpenFlow framework which exposes the data structures
necessary to interface to OpenFlow capable hardware.
- Bro's Intelligence Framework was refactored and new functionality
has been added:
- The framework now supports the new indicator type Intel::SUBNET.
As subnets are matched against seen addresses, the new field 'matched'
in intel.log was introduced to indicate which indicator type(s) caused
the hit.
- The new function remove() allows to delete intelligence items.
- The intel framework now supports expiration of intelligence items.
Expiration can be configured using the new Intel::item_expiration constant
and can be handled by using the item_expired() hook. The new script
do_expire.bro removes expired items.
- The new hook extend_match() allows extending the framework. The new
policy script whitelist.bro uses the hook to implement whitelisting.
- Intel notices are now suppressible and mails for intel notices now
list the identified services as well as the intel source.
- There is a new file entropy analyzer for files.
- Bro now supports the remote framebuffer protocol (RFB) that is used by
VNC servers for remote graphical displays. New log file: rfb.log.
- Bro now supports the Radiotap header for 802.11 frames.
- Bro now has rudimentary IMAP and XMPP analyzers examining the initial
phases of the protocol. Right now these analyzers only identify
STARTTLS sessions, handing them over to TLS analysis. These analyzers
do not yet analyze any further IMAP/XMPP content.
- New funtionality has been added to the SSL/TLS analyzer:
- Bro now supports (draft) TLS 1.3.
- The new event ssl_extension_signature_algorithm() allows access to the
TLS signature_algorithms extension that lists client supported signature
and hash algorithm pairs.
- The new event ssl_extension_key_share gives access to the supported named
groups in TLS 1.3.
- The new event ssl_application_data gives information about application data
that is exchanged before encryption fully starts. This is used to detect
when encryption starts in TLS 1.3.
- Bro now tracks VLAN IDs. To record them inside the connection log,
load protocols/conn/vlan-logging.bro.
- A new dns_CAA_reply() event gives access to DNS Certification Authority
Authorization replies.
- A new per-packet event raw_packet() provides access to layer 2
information. Use with care, generating events per packet is
expensive.
- A new built-in function, decode_base64_conn() for Base64 decoding.
It works like decode_base64() but receives an additional connection
argument that will be used for decoding errors into weird.log
(instead of reporter.log).
- A new get_current_packet_header() bif returns the headers of the current
packet.
- Three new built-in functions for handling set[subnet] and table[subnet]:
- check_subnet(subnet, table) checks if a specific subnet is a member
of a set/table. This is different from the "in" operator, which always
performs a longest prefix match.
- matching_subnets(subnet, table) returns all subnets of the set or table
that contain the given subnet.
- filter_subnet_table(subnet, table) works like matching_subnets, but returns
a table containing all matching entries.
- Several built-in functions for handling IP addresses and subnets were added:
- is_v4_subnet(subnet) checks whether a subnet specification is IPv4.
- is_v6_subnet(subnet) checks whether a subnet specification is IPv6.
- addr_to_subnet(addr) converts an IP address to a /32 subnet.
- subnet_to_addr(subnet) returns the IP address part of a subnet.
- subnet_width(subnet) returns the width of a subnet.
- The IRC analyzer now recognizes StartTLS sessions and enables the SSL
analyzer for them.
- The misc/stats.bro script is now loaded by default and logs more Bro
execution statistics to the stats.log file than it did previously. It
now also uses the standard Bro log format.
- A set of new built-in functions for gathering execution statistics:
get_net_stats(), get_conn_stats(), get_proc_stats(),
get_event_stats(), get_reassembler_stats(), get_dns_stats(),
get_timer_stats(), get_file_analysis_stats(), get_thread_stats(),
get_gap_stats(), get_matcher_stats()
- Two new functions haversine_distance() and haversine_distance_ip()
for calculating geographic distances. The latter function requires that Bro
be built with libgeoip.
- Table expiration timeout expressions are evaluated dynamically as
timestamps are updated.
- The pcap buffer size can be set through the new option Pcap::bufsize.
- Input framework readers stream types Table and Event can now define a custom
event (specified by the new "error_ev" field) to receive error messages
emitted by the input stream. This can, e.g., be used to raise notices in
case errors occur when reading an important input source.
- The logging framework now supports user-defined record separators,
renaming of column names, as well as extension data columns that can
be added to specific or all logfiles (e.g., to add new names).
- The new "bro-config" script can be used to determine the Bro installation
paths.
- New BroControl functionality in aux/broctl:
- There is a new node type "logger" that can be specified in
node.cfg (that file has a commented-out example). The purpose of
this new node type is to receive logs from all nodes in a cluster
in order to reduce the load on the manager node. However, if
there is no "logger" node, then the manager node will handle
logging as usual.
- The post-terminate script will send email if it fails to archive
any log files. These mails can be turned off by changing the
value of the new BroControl option MailArchiveLogFail.
- Added the ability for "broctl deploy" to reload the BroControl
configuration (both broctl.cfg and node.cfg). This happens
automatically if broctl detects any changes to those config files
since the last time the config was loaded. Note that this feature
is relevant only when using the BroControl shell interactively.
- The BroControl plugin API has a new function "broctl_config".
This gives plugin authors the ability to add their own script code
to the autogenerated broctl-config.bro script.
- There is a new BroControl plugin for custom load balancing. This
plugin can be used by setting "lb_method=custom" for your worker
nodes in node.cfg. To support packet source plugins, it allows
configuration of a prefix and suffix for the interface name.
- New Bro plugins in aux/plugins:
- af_packet: Native AF_PACKET support.
- kafka : Log writer interfacing to Kafka.
- myricom: Native Myricom SNF v3 support.
- pf_ring: Native PF_RING support.
- postgresql: A PostgreSQL reader/writer.
- redis: An experimental log writer for Redis.
- tcprs: A TCP-level analyzer detecting retransmissions, reordering, and more.
Changed Functionality
---------------------
- Log changes:
- Connections
The 'history' field gains two new flags: '^' indicates that
Bro heuristically flipped the direction of the connection.
't/T' indicates the first TCP payload retransmission from
originator or responder, respectively.
- Intelligence
New field 'matched' to indicate which indicator type(s) caused the hit.
- DNS
New 'rtt' field to indicate the round trip time between when a
request was sent and when a reply started.
- SMTP
New 'cc' field which includes the 'Cc' header from MIME
messages sent over SMTP.
Changes in 'mailfrom' and 'rcptto' fields to remove some
non-address cruft that will tend to be found. The main
example is the change from ``"<user@domain>"`` to
``"[email protected]"``.
- HTTP
Removed 'filename' field (which was seldomly used).
New 'orig_filenames' and 'resp_filenames' fields which each
contain a vector of filenames seen in entities transferred.
- stats.log
The following fields have been added: active_tcp_conns,
active_udp_conns, active_icmp_conns, tcp_conns, udp_conns,
icmp_conns, timers, active_timers, files, active_files, dns_requests,
active_dns_requests, reassem_tcp_size, reassem_file_size,
reassem_frag_size, reassem_unknown_size.
The following fields have been renamed: lag -> pkt_lag.
The following fields have been removed: pkts_recv.
- The BrokerComm and BrokerStore namespaces were renamed to Broker.
The Broker "print()" function was renamed to Broker::send_print(), and
the "event()" function was renamed to Broker::send_event().
- The constant ``SSH::skip_processing_after_detection`` was removed. The
functionality was replaced by the new constant
``SSH::disable_analyzer_after_detection``.
- The ``net_stats()`` and ``resource_usage()`` functions have been
removed, and their functionality is now provided by the new execution
statistics functions (see above).
- Some script-level identifiers have changed their names:
- snaplen -> Pcap::snaplen
- precompile_pcap_filter() -> Pcap::precompile_pcap_filter()
- install_pcap_filter() -> Pcap::install_pcap_filter()
- pcap_error() -> Pcap::error()
- TCP analysis was changed to process connections without the initial
SYN packet. In the past, connections without a full handshake were
treated as partial, meaning that most application-layer analyzers
would refuse to inspect the payload. Now, Bro will consider these
connections as complete and all analyzers will process them normally.
- The ``policy/misc/capture-loss.bro`` script is now loaded by default.
- The traceroute detection script package ``policy/misc/detect-traceroute``
is no longer loaded by default.
- Changed BroControl functionality in aux/broctl:
- The networks.cfg file now contains private IP space 172.16.0.0/12
by default.
- Upon startup, if broctl can't get IP addresses from the "ifconfig"
command for any reason, then broctl will now also try to use the
"ip" command.
- BroControl will now automatically search the Bro plugin directory
for BroControl plugins (in addition to all the other places where
BroControl searches). This enables automatic loading of
BroControl plugins that are provided by a Bro plugin.
- Changed the default value of the StatusCmdShowAll option so that
the "broctl status" command runs faster. This also means that
there is no longer a "Peers" column in the status output by
default.
- Users can now specify a more granular log expiration interval. The
BroControl option LogExpireInterval can be set to an arbitrary
time interval instead of just an integer number of days. The time
interval is specified as an integer followed by a time unit:
"day", "hr", or "min". For backward compatibility, an integer
value without a time unit is still interpreted as a number of
days.
- Changed the text of crash report emails. Now crash reports tell
the user to forward the mail to the Bro team only when a backtrace
is included in the crash report. If there is no backtrace, then
the crash report includes instructions on how to get backtraces
included in future crash reports.
- There is a new option SitePolicyScripts that replaces SitePolicyStandalone
(the old option is still available, but will be removed in the next
release).
Removed Functionality
---------------------
- The app-stats scripts have been removed because they weren't
being maintained and they were becoming inaccurate (as a result, the
app_stats.log is also gone). They were also prone to needing more regular
updates as the internet changed and will likely be more relevant if
maintained externally.
- The event ack_above_hole() has been removed, as it was a subset
of content_gap() and led to plenty of noise.
- The command line options ``--analyze``, ``--set-seed``, and
``--md5-hashkey`` have been removed.
- The packaging scripts pkg/make-\*-packages are gone. They aren't
used anymore for the binary Bro packages that the project
distributes; haven't been supported in a while; and have
problems.
Deprecated Functionality
------------------------
- The built-in functions decode_base64_custom() and
encode_base64_custom() are no longer needed and will be removed
in the future. Their functionality is now provided directly by
decode_base64() and encode_base64(), which take an optional
parameter to change the Base64 alphabet.
Bro 2.4
=======
New Functionality
-----------------
- Bro now has support for external plugins that can extend its core
functionality, like protocol/file analysis, via shared libraries.
Plugins can be developed and distributed externally, and will be
pulled in dynamically at startup (the environment variables
BRO_PLUGIN_PATH and BRO_PLUGIN_ACTIVATE can be used to specify the
locations and names of plugins to activate). Currently, a plugin
can provide custom protocol analyzers, file analyzers, log writers,
input readers, packet sources and dumpers, and new built-in functions.
A plugin can furthermore hook into Bro's processing at a number of
places to add custom logic.
See https://www.bro.org/sphinx-git/devel/plugins.html for more
information on writing plugins.
- Bro now has support for the MySQL wire protocol. Activity gets
logged into mysql.log.
- Bro now parses DTLS traffic. Activity gets logged into ssl.log.
- Bro now has support for the Kerberos KRB5 protocol over TCP and
UDP. Activity gets logged into kerberos.log.
- Bro now has an RDP analyzer. Activity gets logged into rdp.log.
- Bro now has a file analyzer for Portable Executables. Activity gets
logged into pe.log.
- Bro now has support for the SIP protocol over UDP. Activity gets
logged into sip.log.
- Bro now features a completely rewritten, enhanced SSH analyzer. The
new analyzer is able to determine if logins failed or succeeded in
most circumstances, logs a lot more more information about SSH
sessions, supports v1, and introduces the intelligence type
``Intel::PUBKEY_HASH`` and location ``SSH::IN_SERVER_HOST_KEY``. The
analayzer also generates a set of additional events
(``ssh_auth_successful``, ``ssh_auth_failed``, ``ssh_auth_attempted``,
``ssh_auth_result``, ``ssh_capabilities``, ``ssh2_server_host_key``,
``ssh1_server_host_key``, ``ssh_encrypted_packet``,
``ssh2_dh_server_params``, ``ssh2_gss_error``, ``ssh2_ecc_key``). See
next section for incompatible SSH changes.
- Bro's file analysis now supports reassembly of files that are not
transferred/seen sequentially. The default file reassembly buffer
size is set with the ``Files::reassembly_buffer_size`` variable.
- Bro's file type identification has been greatly improved (new file types,
bug fixes, and performance improvements).
- Bro's scripting language now has a ``while`` statement::
while ( i < 5 )
print ++i;
``next`` and ``break`` can be used inside the loop's body just like
with ``for`` loops.
- Bro now integrates Broker, a new communication library. See
aux/broker/README for more information on Broker, and
doc/frameworks/broker.rst for the corresponding Bro script API.
With Broker, Bro has the similar capabilities of exchanging events and
logs with remote peers (either another Bro process or some other
application that uses Broker). It also includes a key-value store
API that can be used to share state between peers and optionally
allow data to persist on disk for longer-term storage.
Broker support is by default off for now; it can be enabled at
configure time with --enable-broker. It requires CAF version 0.13+
(https://github.com/actor-framework/actor-framework) as well as a
C++11 compiler (e.g. GCC 4.8+ or Clang 3.3+).
Broker will become a mandatory dependency in future Bro versions and
replace the current communication and serialization system.
- Add --enable-c++11 configure flag to compile Bro's source code in
C++11 mode with a corresponding compiler. Note that 2.4 will be the
last version of Bro that compiles without C++11 support.
- The SSL analysis now alerts when encountering SSL connections with
old protocol versions or unsafe cipher suites. It also gained
extended reporting of weak keys, caching of already validated
certificates, and full support for TLS record defragmentation. SSL generally
became much more robust and added several fields to ssl.log (while
removing some others).
- A new icmp_sent_payload event provides access to ICMP payload.
- The input framework's raw reader now supports seeking by adding an
option "offset" to the config map. Positive offsets are interpreted
to be from the beginning of the file, negative from the end of the
file (-1 is end of file).
- One can now raise events when a connection crosses a given size
threshold in terms of packets or bytes. The primary API for that
functionality is in base/protocols/conn/thresholds.bro.
- There is a new command-line option -Q/--time that prints Bro's execution
time and memory usage to stderr.
- BroControl now has a new command "deploy" which is equivalent to running
the "check", "install", "stop", and "start" commands (in that order).
- BroControl now has a new option "StatusCmdShowAll" that controls whether
or not the broctl "status" command gathers all of the status information.
This option can be used to make the "status" command run significantly
faster (in this case, the "Peers" column will not be shown in the output).
- BroControl now has a new option "StatsLogEnable" that controls whether
or not broctl will record information to the "stats.log" file. This option
can be used to make the "broctl cron" command run slightly faster (in this
case, "broctl cron" will also no longer send email about not seeing any
packets on the monitoring interfaces).
- BroControl now has a new option "MailHostUpDown" which controls whether or
not the "broctl cron" command will send email when it notices that a host
in the cluster is up or down.
- BroControl now has a new option "CommandTimeout" which specifies the number
of seconds to wait for a command that broctl ran to return results.
Changed Functionality
---------------------
- bro-cut has been rewritten in C, and is hence much faster.
- File analysis
* Removed ``fa_file`` record's ``mime_type`` and ``mime_types``
fields. The event ``file_sniff`` has been added which provides
the same information. The ``mime_type`` field of ``Files::Info``
also still has this info.
* The earliest point that new mime type information is available is
in the ``file_sniff`` event which comes after the ``file_new`` and
``file_over_new_connection`` events. Scripts which inspected mime
type info within those events will need to be adapted. (Note: for
users that worked w/ versions of Bro from git, for a while there was
also an event called ``file_mime_type`` which is now replaced with
the ``file_sniff`` event).
* Removed ``Files::add_analyzers_for_mime_type`` function.
* Removed ``offset`` parameter of the ``file_extraction_limit``
event. Since file extraction now internally depends on file
reassembly for non-sequential files, "offset" can be obtained
with other information already available -- adding together
``seen_bytes`` and ``missed_bytes`` fields of the ``fa_file``
record gives how many bytes have been written so far (i.e.
the "offset").
- The SSH changes come with a few incompatibilities. The following
events have been renamed:
* ``SSH::heuristic_failed_login`` to ``ssh_auth_failed``
* ``SSH::heuristic_successful_login`` to ``ssh_auth_successful``
The ``SSH::Info`` status field has been removed and replaced with
the ``auth_success`` field. This field has been changed from a
string that was previously ``success``, ``failure`` or
``undetermined`` to a boolean. a boolean that is ``T``, ``F``, or
unset.
- The has_valid_octets function now uses a string_vec parameter instead of
string_array.
- conn.log gained a new field local_resp that works like local_orig,
just for the responder address of the connection.
- GRE tunnels are now identified as ``Tunnel::GRE`` instead of
``Tunnel::IP``.
- The default name for extracted files changed from extract-protocol-id
to extract-timestamp-protocol-id.
- The weird named "unmatched_HTTP_reply" has been removed since it can
be detected at the script-layer and is handled correctly by the
default HTTP scripts.
- When adding a logging filter to a stream, the filter can now inherit
a default ``path`` field from the associated ``Log::Stream`` record.
- When adding a logging filter to a stream, the
``Log::default_path_func`` is now only automatically added to the
filter if it has neither a ``path`` nor a ``path_func`` already
explicitly set. Before, the default path function would always be set
for all filters which didn't specify their own ``path_func``.
- BroControl now establishes only one ssh connection from the manager to
each remote host in a cluster configuration (previously, there would be
one ssh connection per remote Bro process).
- BroControl now uses SQLite to record state information instead of a
plain text file (the file "spool/broctl.dat" is no longer used).
On FreeBSD, this means that there is a new dependency on the package
"py27-sqlite3".
- BroControl now records the expected running state of each Bro node right
before each start or stop. The "broctl cron" command uses this info to
either start or stop Bro nodes as needed so that the actual state matches
the expected state (previously, "broctl cron" could only start nodes in
the "crashed" state, and could never stop a node).
- BroControl now sends all normal command output (i.e., not error messages)
to stdout. Error messages are still sent to stderr, however.
- The capability of processing NetFlow input has been removed for the
time being. Therefore, the -y/--flowfile and -Y/--netflow command-line
options have been removed, and the netflow_v5_header and netflow_v5_record
events have been removed.
- The -D/--dfa-size command-line option has been removed.
- The -L/--rule-benchmark command-line option has been removed.
- The -O/--optimize command-line option has been removed.
- The deprecated fields "hot" and "addl" have been removed from the
connection record. Likewise, the functions append_addl() and
append_addl_marker() have been removed.
- Log files now escape non-printable characters consistently as "\xXX'.
Furthermore, backslashes are escaped as "\\", making the
representation fully reversible.
Deprecated Functionality
------------------------
- The split* family of functions are to be replaced with alternate
versions that return a vector of strings rather than a table of
strings. This also allows deprecation for some related string
concatenation/extraction functions. Note that the new functions use
0-based indexing, rather than 1-based.
The full list of now deprecated functions is:
* split: use split_string instead.
* split1: use split_string1 instead.
* split_all: use split_string_all instead.
* split_n: use split_string_n instead.