When http_reply events are received before http_request events, either
through faking traffic or possible re-ordering, it is possible to trigger
unbounded state growth due to later http_requests never being matched
again with responses.
Prevent this by synchronizing request/response counters when late
requests come in.
Also forcefully flush pending requests when http_replies are never
observed either due to the analyzer having been disabled or because
half-duplex traffic.
Fixes#1705
* origin/topic/awelzel/3145-dcerpc-state-clean:
dce-rpc: Test cases for unbounded state growth
dce-rpc: Handle smb2_close_request() in scripts
smb/dce-rpc: Cleanup DCE-RPC analyzers when fid is closed and limit them
dce-rpc: Do not repeatedly register removal hooks
Roughly 2.5 years ago all events taking the ``icmp_conn`` parameter were
removed with 44ad614094 and the NetVar.cc
type not populated anymore.
Remove the left-overs in script land, too.
This patch does two things:
1) For SMB close requests, tear down any associated DCE-RPC
analyzer if one exists.
2) Protect from fid_to_analyzer_map growing unbounded by introducing a
new SMB::max_dce_rpc_analyzers limit and forcefully wipe the
analyzers if exceeded. Propagate this to script land as event
smb_discarded_dce_rpc_analyzers() for additional cleanup.
This is mostly to fix how the binpac SMB analyzer tracks individual
DCE-RPC analyzers per open fid. Connections that re-open the same or
different pipe may currently allocate unbounded number of analyzers.
Closes#3145.
This is similar to what the external corelight/zeek-smb-clear-state script
does, but leverages the smb2_discarded_messages_state() event instead of
regularly checking on the state of SMB connections.
The pcap was created using the dperson/samba container image and mounting
a share with Linux's CIFS filesystem, then copying the content of a
directory with 100 files. The test uses a BPF filter to imitate mostly
"half-duplex" traffic.
An invalid mail transaction is determined as
* RCPT TO command without a preceding MAIL FROM
* a DATA command without a preceding RCPT TO
and logged as a weird.
The testing pcap for invalid mail transactions was produced with a Python
script against a local exim4 configured to accept more errors and unknown
commands than 3 by default:
# exim4.conf.template
smtp_max_synprot_errors = 100
smtp_max_unknown_commands = 100
See also: https://www.rfc-editor.org/rfc/rfc5321#section-3.3
The user and password fields are replicated to each of the ftp.log
entries. Using a very large username (100s of KBs) allows to bloat
the log without actually sending much traffic. Further, limit the
arg and reply_msg columns to large, but not unbounded values.
* When a file is transferred over multiple connection, have
create_file_info() just pick the first one instead of none.
* Do not unconditionally assume cid and cuid as set on a
Notice::FileInfo object.
oss-fuzz produced FTP traffic with a ~550KB long FTP command. Cap FTP command
length at 100 bytes, log a weird if a command is larger than that and move
on to the next. Likely it's not actual FTP traffic, but raising an
analyzer violation would allow clients an easy way to disable the analyzer
by sending an overly long command.
The added test PCAP was generated using a fake Python socket server/client.
This adds a "policy" hook into the logging framework's streams and
filters to replace the existing log filter predicates. The hook
signature is as follows:
hook(rec: any, id: Log::ID, filter: Log::Filter);
The logging manager invokes hooks on each log record. Hooks can veto
log records via a break, and modify them if necessary. Log filters
inherit the stream-level hook, but can override or remove the hook as
needed.
The distribution's existing log streams now come with pre-defined
hooks that users can add handlers to. Their name is standardized as
"log_policy" by convention, with additional suffixes when a module
provides multiple streams. The following adds a handler to the Conn
module's default log policy hook:
hook Conn::log_policy(rec: Conn::Info, id: Log::ID, filter: Log::Filter)
{
if ( some_veto_reason(rec) )
break;
}
By default, this handler will get invoked for any log filter
associated with the Conn::LOG stream.
The existing predicates are deprecated for removal in 4.1 but continue
to work.
* 'action-drop' of https://github.com/LBL-gov/zeek:
Moved verb ACTION_DROP from policy/frameworks/netcontrol/catch-and-release.zeek to base/frameworks/notice/main.zeek.
ACTION_DROP is not only part of catch-n-release subsystem.
Also, historically ACTION_DROP has been bundled with ACTION_LOG, ACTION_ALARM, ACTION_EMAIL... and its helpful that this verb remains in base/frameworks/notice/main.zeek
This introduces a new sampling state-map for expired connections to fix
segfaults that previously occured when passing in a `connection` record
to `Reporter::conn_weird()` for which the internal `Connection` object
had already been expired and deleted. This also introduces a new event
called `expired_conn_weird`, which is similar to `conn_weird`, except
the full `connection` record is no longer available, just the `conn_id`
and UID string.
In the past they were processed on the manager - which requires big
records to be sent around.
This has a potential of incompatibilities if someone relied on global
state for notice processing.
GH-214
* "bro_is_terminating" is now "zeek_is_terminating"
* "bro_version" is now "zeek_version"
The old function names still exist for now, but are deprecated.
These are no longer loaded by default due to the performance impact they
cause simply by being loaded (they have event handlers for commonly
generated events) and they aren't generally useful enough to justify it.
For backward compatibility when reading values, we first check
the ZEEK-prefixed value, and if not set, then check the corresponding
BRO-prefixed value.
* All "Broxygen" usages have been replaced in
code, documentation, filenames, etc.
* Sphinx roles/directives like ":bro:see" are now ":zeek:see"
* The "--broxygen" command-line option is now "--zeexygen"
