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zeek/NEWS
Robin Sommer f830ed3edf s/bro-ids.org/bro.org/g
2013-03-07 19:33:04 -08:00

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Release Notes
=============
This document summarizes the most important changes in the current Bro
release. For a complete list of changes, see the ``CHANGES`` file
(note that submodules, such as BroControl and Broccoli, come with
their own CHANGES.)
Bro 2.2
-------
New Functionality
~~~~~~~~~~~~~~~~~
- GPRS Tunnelling Protocol (GTPv1) decapsulation.
- GridFTP support. TODO: Extend.
- ssl.log now also records the subject client and issuer certificates.
- Hooks: TODO: Briefly summarize the documention from
doc/scripts/builtins.rst here.
- The ASCII writer can now output CSV files on a per filter basis.
- Bro's language now has a working "switch" statement that generally
behaves like C-style switches except case labels can be comprised of
multiple literal constants delimited by commas. Only atomic types
are allowed for now. Case label bodies that don't execute a
"return" or "break" statement will fall through to subsequent cases.
A default case label is allowed.
- Bro's language now has a new set of types "opaque of X". Opaque
values can be passed around like other values but they can only be
manipulated with BiF functions, not with other operators. Currently,
the following opaque types are supported:
- opaque of md5
- opaque of sha1
- opaque of sha256
- opaquey of entropy.
They go along with the corrsponding BiF functions md5_*, sha1_*,
sha256_*, and entropy_*, respectively. Note that these functions
have changed their signatures to work with opaques types rather
than global state as it was before.
- Strings now support the subscript operator to extract individual
characters and substrings (e.g., s[4], s[1,5]). The index expression
can take up to two indices for the start and end index of the
substring to return (e.g. "mystring[1,3]").
Changed Functionality
~~~~~~~~~~~~~~~~~~~~~
- We removed the following, already deprecated, functionality:
* Scripting language:
- &disable_print_hook attribute.
* BiF functions:
- parse_dotted_addr(), dump_config(),
make_connection_persistent(), generate_idmef(),
split_complete()
- md5_*, sha1_*, sha256_*, and entropy_* have all changed
their signatures to work with opaque types (see above).
- Removed a now unused argument from "do_split" helper function.
- "this" is no longer a reserved keyword.
- The Input Framework's update_finished event has been renamed to
end_of_data. It will now not only fire after table-reads have been
completed, but also after the last event of a whole-file-read (or
whole-db-read, etc.).
- Renamed the option defining the frequency of alarm summary mails to
'Logging::default_alarm_mail_interval'. When using BroControl, the
value can now be set with the new broctl.cfg option
"MailAlarmsInterval".
- We have completely reworded the "notice_policy" mechanism. It now no
linger uses a record of policy items but a "hook", a new language
element that's roughly equivalent to a function with multiple
bodies. The documentation [TODO: insert link] describes how to use
the new notice policy. For existing code, the two main changes are:
- What used to be a "redef" of "Notice::policy" now becomes a hook
implementation. Example:
Old:
redef Notice::policy += {
[$pred(n: Notice::Info) = {
return n$note == SSH::Login && n$id$resp_h == 10.0.0.1;
},
$action = Notice::ACTION_EMAIL]
};
New:
hook Notice::policy(n: Notice::Info)
{
if ( n$note == SSH::Login && n$id$resp_h == 10.0.0.1 )
add n$actions[Notice::ACTION_EMAIL];
}
- notice() is now likewise a hook, no longer an event. If you have
handlers for that event, you'll likely just need to change the
type accordingly. Example:
Old:
event notice(n: Notice::Info) { ... }
New:
hook notice(n: Notice::Info) { ... }
- The notice_policy.log is gone. That's a result of the new notice
policy setup.
- Removed the byte_len() and length() bif functions. Use the "|...|"
operator instead.
Bro 2.1
-------
New Functionality
~~~~~~~~~~~~~~~~~
- Bro now comes with extensive IPv6 support. Past versions offered
only basic IPv6 functionality that was rarely used in practice as it
had to be enabled explicitly. IPv6 support is now fully integrated
into all parts of Bro including protocol analysis and the scripting
language. It's on by default and no longer requires any special
configuration.
Some of the most significant enhancements include support for IPv6
fragment reassembly, support for following IPv6 extension header
chains, and support for tunnel decapsulation (6to4 and Teredo). The
DNS analyzer now handles AAAA records properly, and DNS lookups that
Bro itself performs now include AAAA queries, so that, for example,
the result returned by script-level lookups is a set that can
contain both IPv4 and IPv6 addresses. Support for the most common
ICMPv6 message types has been added. Also, the FTP EPSV and EPRT
commands are now handled properly. Internally, the way IP addresses
are stored has been improved, so Bro can handle both IPv4
and IPv6 by default without any special configuration.
In addition to Bro itself, the other Bro components have also been
made IPv6-aware by default. In particular, significant changes were
made to trace-summary, PySubnetTree, and Broccoli to support IPv6.
- Bro now decapsulates tunnels via its new tunnel framework located in
scripts/base/frameworks/tunnels. It currently supports Teredo,
AYIYA, IP-in-IP (both IPv4 and IPv6), and SOCKS. For all these, it
logs the outer tunnel connections in both conn.log and tunnel.log,
and then proceeds to analyze the inner payload as if it were not
tunneled, including also logging that session in conn.log. For
SOCKS, it generates a new socks.log in addition with more
information.
- Bro now features a flexible input framework that allows users to
integrate external information in real-time into Bro while it's
processing network traffic. The most direct use-case at the moment
is reading data from ASCII files into Bro tables, with updates
picked up automatically when the file changes during runtime. See
doc/input.rst for more information.
Internally, the input framework is structured around the notion of
"reader plugins" that make it easy to interface to different data
sources. We will add more in the future.
- BroControl now has built-in support for host-based load-balancing
when using either PF_RING, Myricom cards, or individual interfaces.
Instead of adding a separate worker entry in node.cfg for each Bro
worker process on each worker host, it is now possible to just
specify the number of worker processes on each host and BroControl
configures everything correctly (including any neccessary enviroment
variables for the balancers).
This change adds three new keywords to the node.cfg file (to be used
with worker entries): lb_procs (specifies number of workers on a
host), lb_method (specifies what type of load balancing to use:
pf_ring, myricom, or interfaces), and lb_interfaces (used only with
"lb_method=interfaces" to specify which interfaces to load-balance
on).
- Bro's default ASCII log format is not exactly the most efficient way
for storing and searching large volumes of data. An alternatives,
Bro now comes with experimental support for two alternative output
formats:
* DataSeries: an efficient binary format for recording structured
bulk data. DataSeries is developed and maintained at HP Labs.
See doc/logging-dataseries for more information.
* ElasticSearch: a distributed RESTful, storage engine and search
engine built on top of Apache Lucene. It scales very well, both
for distributed indexing and distributed searching. See
doc/logging-elasticsearch.rst for more information.
Note that at this point, we consider Bro's support for these two
formats as prototypes for collecting experience with alternative
outputs. We do not yet recommend them for production (but welcome
feedback!)
Changed Functionality
~~~~~~~~~~~~~~~~~~~~~
The following summarizes the most important differences in existing
functionality. Note that this list is not complete, see CHANGES for
the full set.
- Changes in dependencies:
* Bro now requires CMake >= 2.6.3.
* On Linux, Bro now links in tcmalloc (part of Google perftools)
if found at configure time. Doing so can significantly improve
memory and CPU use.
On the other platforms, the new configure option
--enable-perftools can be used to enable linking to tcmalloc.
(Note that perftools's support for non-Linux platforms may be
less reliable).
- The configure switch --enable-brov6 is gone.
- DNS name lookups performed by Bro now also query AAAA records. The
results of the A and AAAA queries for a given hostname are combined
such that at the scripting layer, the name resolution can yield a
set with both IPv4 and IPv6 addresses.
- The connection compressor was already deprecated in 2.0 and has now
been removed from the code base.
- We removed the "match" statement, which was no longer used by any of
the default scripts, nor was it likely to be used by anybody anytime
soon. With that, "match" and "using" are no longer reserved keywords.
- The syntax for IPv6 literals changed from "2607:f8b0:4009:802::1012"
to "[2607:f8b0:4009:802::1012]".
- Bro now spawns threads for doing its logging. From a user's
perspective not much should change, except that the OS may now show
a bunch of Bro threads.
- We renamed the configure option --enable-perftools to
--enable-perftools-debug to indicate that the switch is only relevant
for debugging the heap.
- Bro's ICMP analyzer now handles both IPv4 and IPv6 messages with a
joint set of events. The `icmp_conn` record got a new boolean field
'v6' that indicates whether the ICMP message is v4 or v6.
- Log postprocessor scripts get an additional argument indicating the
type of the log writer in use (e.g., "ascii").
- BroControl's make-archive-name script also receives the writer
type, but as its 2nd(!) argument. If you're using a custom version
of that script, you need to adapt it. See the shipped version for
details.
- Signature files can now be loaded via the new "@load-sigs"
directive. In contrast to the existing (and still supported)
signature_files constant, this can be used to load signatures
relative to the current script (e.g., "@load-sigs ./foo.sig").
- The options "tunnel_port" and "parse_udp_tunnels" have been removed.
Bro now supports decapsulating tunnels directly for protocols it
understands.
- ASCII logs now record the time when they were opened/closed at the
beginning and end of the file, respectively (wall clock). The
options LogAscii::header_prefix and LogAscii::include_header have
been renamed to LogAscii::meta_prefix and LogAscii::include_meta,
respectively.
- The ASCII writers "header_*" options have been renamed to "meta_*"
(because there's now also a footer).
Bro 2.0
-------
As the version number jump suggests, Bro 2.0 is a major upgrade and
lots of things have changed. We have assembled a separate upgrade
guide with the most important changes compared to Bro 1.5 at
http://www.bro.org/documentation/upgrade.html. You can find
the offline version of that document in ``doc/upgrade.rst.``.
Compared to the earlier 2.0 Beta version, the major changes in the
final release are:
* The default scripts now come with complete reference
documentation. See
http://www.bro.org/documentation/index.html.
* libz and libmagic are now required dependencies.
* Reduced snaplen default from 65535 to old default of 8192. The
large value was introducing performance problems on many
systems.
* Replaced the --snaplen/-l command line option with a
scripting-layer option called "snaplen". The new option can also
be redefined on the command line, e.g. ``bro -i eth0
snaplen=65535``.
* Reintroduced the BRO_LOG_SUFFIX environment variable that the
ASCII logger now respects to add a suffix to the log files it
creates.
* The ASCII logs now include further header information, and
fields set to an empty value are now logged as ``(empty)`` by
default (instead of ``-``, which is already used for fields that
are not set at all).
* Some NOTICES were renamed, and the signatures of some SSL events
have changed.
* bro-cut got some new capabilities:
- If no field names are given on the command line, we now pass
through all fields.
- New options -u/-U for time output in UTC.
- New option -F to give output field separator.
* Broccoli supports more types internally, allowing to send
complex records.
* Many smaller bug fixes, portability improvements, and general
polishing across all modules.
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