This rule will match on the STREAM_3WHS_ACK_DATA_INJECT, that is
set if we're:
- in IPS mode
- get a data packet from the server
- that matches the exact SEQ/ACK expectations for the 3whs
The action of the rule is set to drop as the stream engine will drop.
So the rule action is actually not needed, but for consistency it
is drop.
If we have only seen the SYN and SYN/ACK of the 3whs, accept from
server data if it perfectly matches the SEQ/ACK expectations. This
might happen in 2 scenarios:
1. packet loss: if we lost the final ACK, we may get data that fits
this pattern (e.g. a SMTP EHLO message).
2. MOTS/MITM packet injection: an attacker can send a data packet
together with its SYN/ACK packet. The client due to timing almost
certainly gets the SYN/ACK before considering the data packet,
and will respond with the final ACK before processing the data
packet.
In IDS mode we will accept the data packet and rely on the reassembly
engine to warn us if the packet was indeed injected.
In IPS mode we will drop the packet. In the packet loss case we will
rely on retransmissions to get the session back up and running. For
the injection case we blocked this injection attempt.
The detect engine would bypass packets that are set as dropped. This
seems sane, as these packets are going to be dropped anyway.
However, it lead to the following corner case: stream events that
triggered the drop could not be matched on the rules. The packet
with the event wouldn't make it to the detect engine due to the bypass.
This patch changes the logic to not bypass DROP packets anymore.
Packets that are dropped by the stream engine will set the no payload
inspection flag, so avoid needless cost.
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"}
READ replies with large data chunks are processed partially to avoid
queuing too much data. When the final chunk was received however, the
start of the chunk would already tag the transaction as 'done'. The
more aggressive tx freeing that was recently merged would cause this
tx to be freed before the rest of the in-progress chunk was done.
This patch delays the tagging of the tx until the final data has been
received.
This commit fixes a leak of mmap'ed ring buffer that was not
unmaped when a socket was closed. In addition, the leak could
break an inline channel on certain configurations.
Also slightly changed AFPCreateSocket():
1. If an interface is not up, it does not try to apply any
settings to a socket. This reduces a number of error messages
while an interface is down.
2. Interface is considered active if both IFF_UP and IFF_RUNNING
are present.
So far, the suricata socket suricata-command.socket has the rights
rw-r----- suricata:user.
When suricata is used with restricted access, an other application
(suricatasc like) that needs to access to the command socket also
with restricted access can not write to the socket since it is not
the owner (e.g suricata within container, with an hardened value
for umask and hardened rights for users).
The socket should be set as rw-rw----. Use chmod instead of fchmod
and set it after the socket creation.
https://redmine.openinfosecfoundation.org/issues/2412
Suricatasc is not supporting pcap-file processing in continuous mode.
Register a new command pcap-file-continuous in the unix manager to work
with suricatasc. Add defaulted arguments for pcap-file to support
backwards compatibility.
RAND_MAX is not guaranteed to be a divisor of ULONG_MAX, so take the
necessary precautions to get unbiased random numbers. Although the
bias might be negligible, it's not advisable to rely on it.
according to its man page, sigprocmask has undefined behavior in
multithreaded environments. Instead of explictly blocking the handling
of SIGUSR2 in every thread, direct block handling SIGUSR2 before
creating the threads and enable again the handling of this signal
afterwards. In this way, only the main thread will be able to manage
this signal properly.
Add startswith modifier to simplify matching patterns at the start
of a buffer.
Instead of:
content:"abc"; depth:3;
This enables:
content:"abc"; startswith;
Especially with longer patterns this makes the intention of the rule
more clear and eases writing the rules.
Internally it's simply a shorthand for 'depth:<pattern len>;'.
Ticket https://redmine.openinfosecfoundation.org/issues/742
Fix the inspection of multiple files in a single TX, where new files
may be added to the TX after inspection started.
Assign the hard coded id DE_STATE_FLAG_FILE_INSPECT to the file
inspect engine.
Make sure that sigs that do file inspection and don't match on the
current file always store a detailed state. This state will include
the DE_STATE_FLAG_FILE_INSPECT flag.
When the app-layer indicates a new file is available, for each sig
that has the DE_STATE_FLAG_FILE_INSPECT flag set, reset part of the
state so that the sig is evaluated again.
Free txs that are done out of order if we can. Some protocol
implementations have transactions running in parallel, where it is
possible that a tx that started later finishes earlier than other
transactions. Support freeing those.
Also improve handling on asynchronious transactions. If transactions
are unreplied, e.g. in the dns flood case, the parser may at some
point free transactions on it's own. Handle this case in
the app-layer engine so that the various tracking id's (inspect, log,
and 'min') are updated accordingly.
Next, free txs much more aggressively. Instead of freeing old txs
at the app-layer parsing stage, free all complete txs at the end
of the flow-worker. This frees txs much sooner in many cases.
When stateless rules are depending on a flowbit being set by a stateful
rule, the inspection order is almost certainly wrong.
Switch stateless rules depending on stateful rules to being stateful.
This is used to turn 'TCP stream' inspecting rules (which are stateless
unless mixed with stateful keywords) into stateful rules.
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.
Victor Julien
Pascal Delalande
Clement Galland
Jason Ish
Alexander Gozman
Danny Browning
Martin Natano
Maurizio Abba
Ruslan Usmanov