There are two new script level functions to query and lookup files
from the core by their IDs. These are adding feature parity for
similarly named functions for files. The function prototypes are
as follows:
Files::file_exists(fuid: string): bool
Files::lookup_File(fuid: string): fa_file
Some of the existing mime types received extended matchers
to fix problems with UTF-16 BOMs.
New file mime types:
- .ini files
- MS Registry policy files
- MS Registry files
- MS Registry format files (e.g. DESKTOP.DAT)
- MS Outlook PST files
- Apple AFPInfo files
Mime type fixes:
- MP3 files with ID3 tags.
- JSON and XML matchers were extended
* origin/topic/seth/more-file-type-ident-fixes:
File API updates complete.
Fixes for file type identification.
API changes to file analysis mime type detection.
Make HTTP 206 reassembly require ETags by default.
More file type identification improvements
Fix an issue with files having gaps before the bof_buffer is filled.
Fix an issue with packet loss in http file reporting.
Adding WOFF fonts to file type identification.
Extended JSON matching and added OCSP responses.
Another large signature update.
More signature updates.
Even more file type ident clean up.
Lots of fixes for file type identification.
BIT-1368 #merged
- Backed out eTag changes. The real world is more complicated
than just using eTags to identify the same file.
- A bit of code simplication in the http base scripts.
- Test updates (more existing small problems were identified!).
-
Removed "file_mime_type" and "file_mime_types" event, replacing them
with a new event called "file_metadata_inferred". It has a record
argument of type "inferred_file_metadata", which contains the mime type
information that the earlier events used to supply. The idea here is
that future extensions to the record with new metadata will be less
likely to break user code than the alternatives (adding new events or
new event parameters).
Addresses BIT-1368.
- Lots of cleanup and expansion of XML match types.
- Signatures for ATOM and RSS (text/atom, text/rss).
- Improved SOAP signature.
- Improved text/cross-domain-policy signature
- Improved and expanded javascript matching a bit.
- Removed a lot of potentially problematic signatures (performance)
- Split out more signatures from libmagic.sig
- Added a signature for matching JSON. Seems to work ok.
- Signature for MPEGv4 audio.
- Expanded java applet signature.
- Improved PNG matching.
- Improved MP3 matching.
This allows the path for the default filter to be specified explicitly
when creating a stream and reduces the need to rely on the default path
function to magically supply the path.
The default path function is now only used if, when a filter is added to
a stream, it has neither a path nor a path function already.
Adapted the existing Log::create_stream calls to explicitly specify a
path value.
Addresses BIT-1324
- Plain text now identified with BOMs for UTF8,16,32
(even though 16 and 32 wouldn't get identified as plain text, oh-well)
- X.509 certificates are now populating files.log with
the mime type application/pkix-cert.
- File signatures are split apart into file types
to help group and organize signatures a bit better.
- Normalized some FILE_ANALYSIS debug messages.
- Improved Javascript detection.
- Improved HTML detection.
- Removed a bunch of bad signatures.
- Merged a bunch of signatures that ultimately detected
the same mime type.
- Added detection for MS LNK files.
- Added detection for cross-domain-policy XML files.
- Added detection for SOAP envelopes.
- Re-arrange how some fa_file fields (e.g. source, connection info, mime
type) get updated/set for consistency.
- Add more robust mechanisms for flushing the reassembly buffer.
The goal being to report all gaps and deliveries to file analyzers
regardless of the state of the reassembly buffer at the time it has to
be flushed.
- Remove all of the x-c detections. Nearly all false
positives.
- Remove the back up TAR detections. Not very helpful.
- Remove one of the x-elc detections that was too loose
and caused many false positives.
- Change to the default BOF buffer size to 3000 (was 1024).
- Reorganized MS signatures into a separate file
- Improved lots of the signatures and added new ones.
- This moves the signatures out of the libmagic imported signatures
and into our own general.sig.
- Expand the detection to LZMA compressed flash files.
with a MIME type.
Whenever that MIME is detected, Bro will now automatically activate
the analyzer. The interface mimics how well-known ports are defined
for protocol analyzers.
This isn't actually used by any existing file analyzer (because we
don't have any yet that target a specific file format), but there's a
test making sure it works.
* origin/topic/jsiwek/file-signatures:
File type detection changes and fix https.log {orig,resp}_fuids fields.
Various minor changes related to file mime type detection.
Refactor common MIME magic matching code.
Replace libmagic w/ Bro signatures for file MIME type identification.
Conflicts:
scripts/base/init-default.bro
testing/btest/Baseline/coverage.bare-load-baseline/canonified_loaded_scripts.log
testing/btest/Baseline/coverage.default-load-baseline/canonified_loaded_scripts.log
BIT-1143 #merged
- Removed "binary" and "octet-stream" mime type detections. They don't
provide any more information than an uninitialized mime_type field
which implicitly means no magic signature matches and so the media
type is unknown to Bro.
- Slight change to "text/plain" signature. It's still not the most
accurate, which is reflected in its -20 strength value.
- The logic for adding file ids to {orig,resp}_fuids fields of
the http.log incorrectly depended on the state of
{orig,resp}_mime_types fields, so sometimes not all file ids
associated w/ the session were logged.
- Improve or just remove some file magic signatures ported from libmagic
that were too general and matched incorrectly too often.
- Fix MHR script's use of fa_file$mime_type before checking if it's
initialized. It may be uninitialized if no signatures match.
- The "fa_file" record now contains a "mime_types" field that contains
all magic signatures that matched the file content (where the
"mime_type" field is just a shortcut for the strongest match).
Notable changes:
- libmagic is no longer used at all. All MIME type detection is
done through new Bro signatures, and there's no longer a means to get
verbose file type descriptions (e.g. "PNG image data, 1435 x 170").
The majority of the default file magic signatures are derived
from the default magic database of libmagic ~5.17.
- File magic signatures consist of two new constructs in the
signature rule parsing grammar: "file-magic" gives a regular
expression to match against, and "file-mime" gives the MIME type
string of content that matches the magic and an optional strength
value for the match.
- Modified signature/rule syntax for identifiers: they can no longer
start with a '-', which made for ambiguous syntax when doing negative
strength values in "file-mime". Also brought syntax for Bro script
identifiers in line with reality (they can't start with numbers or
include '-' at all).
- A new Built-In Function, "file_magic", can be used to get all
file magic matches and their corresponding strength against a given
chunk of data
- The second parameter of the "identify_data" Built-In Function
can no longer be used to get verbose file type descriptions, though it
can still be used to get the strongest matching file magic signature.
- The "file_transferred" event's "descr" parameter no longer
contains verbose file type descriptions.
- The BROMAGIC environment variable no longer changes any behavior
in Bro as magic databases are no longer used/installed.
- Reverted back to minimum requirement of CMake 2.6.3 from 2.8.0
(it's back to being the same requirement as the Bro v2.2 release).
The bump was to accomodate building libmagic as an external project,
which is no longer needed.
Addresses BIT-1143.
- The reassembly behavior can be modified per-file by enabling or
disabling the reassembler and/or modifying the size of the reassembly
buffer.
- Changed the file extraction analyzer to use the stream to avoid
issues with the chunk based approach not immediately triggering
the file_new event due to mime-type detection delay. Early chunks
frequently ended up lost before.
- Generally things are working now and I'd consider this in testing.
- Enable manager to associate analyzers with a MIME type. With that,
one can now say enable all analyzers for, e.g., "image/gif". This is
exposed to script-land as
Files::add_analyzers_for_mime_type(f: fa_file, mtype: string)
For MIME types identified via libmagic, this happens automatically
(via the file_new() handler in files/main.bro).
- Extend the analyzer API to better match that of protocol analyzers:
- Adding unique analyzer IDs so that we can refer to instances
from script-land.
- Adding subtypes to Components so that a single analyzer
implementation can support different types of analyzers
internally.
- Add an analyzer method SetTag() that allows to set the tag after
construction.
- Adding Init() and Done() methods for consistency with what other
classes offer.
- Add debug logging to the file_analysis stream.
TODO: test cases missing for the new script-land functionality.
Fixed reference to wrong field name.
Added documentation of a function arg.
Added a couple references to other parts of the documentation.
Explained how not specifying extraction filename results in automatic
filename generation.
Several other minor clarifications.
