When Suricata picks up a flow it assumes the first packet is
toserver. In a perfect world without packet loss and where all
sessions neatly start after Suricata itself started, this would be
true. However, in reality we have to account for packet loss and
Suricata starting to get packets for flows already active be for
Suricata is (re)started.
The protocol records on the wire would often be able to tell us more
though. For example in SMB1 and SMB2 records there is a flag that
indicates whether the record is a request or a response. This patch
is enabling the procotol detection engine to utilize this information
to 'reverse' the flow.
There are three ways in which this is supported in this patch:
1. patterns for detection are registered per direction. If the proto
was not recognized in the traffic direction, and midstream is
enabled, the pattern set for the opposing direction is also
evaluated. If that matches, the flow is considered to be in the
wrong direction and is reversed.
2. probing parsers now have a way to feed back their understanding
of the flow direction. They are now passed the direction as
Suricata sees the traffic when calling the probing parsers. The
parser can then see if its own observation matches that, and
pass back it's own view to the caller.
3. a new pattern + probing parser set up: probing parsers can now
be registered with a pattern, so that when the pattern matches
the probing parser is called as well. The probing parser can
then provide the protocol detection engine with the direction
of the traffic.
The process of reversing takes a multi step approach as well:
a. reverse the current packets direction
b. reverse most of the flows direction sensitive flags
c. tag the flow as 'reversed'. This is because the 5 tuple is
*not* reversed, since it is immutable after the flows creation.
Most of the currently registered parsers benefit already:
- HTTP/SMTP/FTP/TLS patterns are registered per direction already
so they will benefit from the pattern midstream logic in (1)
above.
- the Rust based SMB parser uses a mix of pattern + probing parser
as described in (3) above.
- the NFS detection is purely done by probing parser and is updated
to consider the direction in that parser.
Other protocols, such as DNS, are still to do.
Ticket: #2572
This is a DHCP decoder and logger written in Rust. Unlike most
parsers, this one is stateless so responses are not matched
up to requests by Suricata. However, the output does contain
enough fields to match them up in post-processing.
Rules are included to alert of malformed or truncated options.
Add a new parser for Internet Key Exchange version (IKEv2), defined in
RFC 7296.
The IKEv2 parser itself is external. The embedded code includes the
parser state and associated variables, the state machine, and the
detection code.
The parser looks the first two messages of a connection, and analyzes
the client and server proposals to check the cryptographic parameters.
TFTP parsing and logging written in Rust.
Log on eve.json the type of request (read or write), the name of the file and
the mode.
Example of output:
"tftp":{"packet":"read","file":"rfc1350.txt","mode":"octet"}
Use per tx detect_flags to track prefilter. Detect flags are used for 2
things:
1. marking tx as fully inspected
2. tracking already run prefilter (incl mpm) engines
This supercedes the MpmIDs API for directionless tracking
of the prefilter engines.
When we have no SGH we have to flag the txs that are 'complete'
as inspected as well.
Special handling for the stream engine:
If a rule mixes TX inspection and STREAM inspection, we can encounter
the case where the rule is evaluated against multiple transactions
during a single inspection run. As the stream data is exactly the same
for each of those runs, it's wasteful to rerun inspection of the stream
portion of the rule.
This patch enables caching of the stream 'inspect engine' result in
the local 'RuleMatchCandidateTx' array. This is valid only during the
live of a single inspection run.
Remove stateful inspection from 'mask' (SignatureMask). The mask wasn't
used in most cases for those rules anyway, as there we rely on the
prefilter. Add a alproto check to catch the remaining cases.
When building the active non-mpm/non-prefilter list check not just
the mask, but also the alproto. This especially helps stateful rules
with negated mpm.
Simplify AppLayerParserHasDecoderEvents usage in detection to only
return true if protocol detection events are set. Other detection is done
in inspect engines.
Move rule group lookup and handling into it's own function. Handle
'post lookup' tasks immediately, instead of after the first detect
run. The tasks were independent of the initial detection.
Many cleanups and much refactoring.
Use expectation to be able to identify connections that are
ftp data. It parses the PASV response, STOR message and the
RETR message to provide extraction of files.
Implementation in Rust of FTP messages parsing is available.
Also this patch changes some var name prefixed by ssh to ftp.
Add StringToAppProto to map a protocol name to a AppProto.
Exposing this function is required to let parsers discover their
AppProto identifier constant dynamically.
For example, a parser can request this value, and use it for
registration without knowing the value.
Since the parser now also does nfs2, the name nfs3 became confusing.
As it's still in beta, we can rename so this patch renames all 'nfs3'
logic to simply 'nfs'.
Add support for the ENIP/CIP Industrial protocol
This is an app layer implementation which uses the "enip" protocol
and "cip_service" and "enip_command" keywords
Implements AFL entry points
Decode Modbus request and response messages, and extracts
MODBUS Application Protocol header and the code function.
In case of read/write function, extracts message contents
(read/write address, quantity, count, data to write).
Links request and response messages in a transaction according to
Transaction Identifier (transaction management based on DNS source code).
MODBUS Messaging on TCP/IP Implementation Guide V1.0b
(http://www.modbus.org/docs/Modbus_Messaging_Implementation_Guide_V1_0b.pdf)
MODBUS Application Protocol Specification V1.1b3
(http://www.modbus.org/docs/Modbus_Application_Protocol_V1_1b3.pdf)
Based on DNS source code.
Signed-off-by: David DIALLO <diallo@et.esia.fr>
app-layer.[ch], app-layer-detect-proto.[ch] and app-layer-parser.[ch].
Things addressed in this commit:
- Brings out a proper separation between protocol detection phase and the
parser phase.
- The dns app layer now is registered such that we don't use "dnstcp" and
"dnsudp" in the rules. A user who previously wrote a rule like this -
"alert dnstcp....." or
"alert dnsudp....."
would now have to use,
alert dns (ipproto:tcp;) or
alert udp (app-layer-protocol:dns;) or
alert ip (ipproto:udp; app-layer-protocol:dns;)
The same rules extend to other another such protocol, dcerpc.
- The app layer parser api now takes in the ipproto while registering
callbacks.
- The app inspection/detection engine also takes an ipproto.
- All app layer parser functions now take direction as STREAM_TOSERVER or
STREAM_TOCLIENT, as opposed to 0 or 1, which was taken by some of the
functions.
- FlowInitialize() and FlowRecycle() now resets proto to 0. This is
needed by unittests, which would try to clean the flow, and that would
call the api, AppLayerParserCleanupParserState(), which would try to
clean the app state, but the app layer now needs an ipproto to figure
out which api to internally call to clean the state, and if the ipproto
is 0, it would return without trying to clean the state.
- A lot of unittests are now updated where if they are using a flow and
they need to use the app layer, we would set a flow ipproto.
- The "app-layer" section in the yaml conf has also been updated as well.
Per packet per app layer parser profiling. Example summary output:
Per App layer parser stats:
App Layer IP ver Proto cnt min max avg
-------------------- ------ ----- ------ ------ ---------- -------
ALPROTO_HTTP IPv4 6 163394 126 38560320 42814
ALPROTO_FTP IPv4 6 644 117 26100 2566
ALPROTO_TLS IPv4 6 670 117 7137 799
ALPROTO_SMB IPv4 6 114794 126 225270 957
ALPROTO_DCERPC IPv4 6 5207 126 25596 1266
Also added to the csv out.
In the csv out there is a new column "stream (no app)" that removes the
app layer parsers from the stream tracking. So raw stream engine performance
becomes visible.
First version of a simple pattern based L7 proto detection engine. Currently just works by matching a single pattern in the initial data. Implemented HTTP, SSL, MSN, JABBER, SMTP and a few more.
Couple of pattern matcher cleanups.
Victor Julien
Jason Ish
Pierre Chifflier
Clement Galland
Eric Leblond
kwong
DIALLO David
Anoop Saldanha
Anoop Saldanha
Gurvinder Singh
Kirby Kuehl
William Metcalf
Kirby Kuehl