This commit adds support for the Remote Framebuffer Protocol (RFB) as
used, for example, by various VNC implementations. It targets the
official versions 3.3, 3.7 and 3.8 of the protocol and provides logging
for the RFB handshake communication for now. Logged events include
endpoint versions, details of the security (i.e. authentication)
exchange as well as metadata about the image transfer parameters.
Detection is enabled using keywords for:
- rfb.name: Session name as sticky buffer
- rfb.sectype: Security type, e.g. VNC-style challenge-response
- rfb.secresult: Result of the security exchange, e.g. OK, FAIL, ...
The latter could be used, for example, to detect brute-force attempts
on open VNC servers, while the name could be used to map unwanted VNC
sessions to the desktop owners or machines.
We also ship example EVE-JSON output and keyword docs as part of the
Sphinx source for Suricata's RTD documentation.
Add a rule keyword, dns.opcode to match on the opcode flag
found in the DNS request and response headers.
Only exact matches are allowed with negation.
Examples:
- dns.opcode:4;
- dns.opcode:!1;
Datasets are sets/lists of data that can be accessed or added from
the rule language.
This patch implements 3 data types:
1. string (or buffer)
2. md5
3. sha256
The patch also implements 2 new rule keywords:
1. dataset
2. datarep
The dataset keyword allows matching against a list of values to see if
it exists or not. It can also add the value to the set. The set can
optionally be stored to disk on exit.
The datarep support matching/lookups only. With each item in the set a
reputation value is stored and this value can be matched against. The
reputation value is unsigned 16 bit, so values can be between 0 and 65535.
Datasets can be registered in 2 ways:
1. through the yaml
2. through the rules
The goal of this rules based approach is that rule writers can start using
this without the need for config changes.
A dataset is implemented using a thash hash table. Each dataset is its own
separate thash.
Match on JA3S hash using ja3s.hash keyword, e.g:
alert tls any any -> any any (msg:"ja3s.hash test";
ja3s.hash; content:"b26c652e0a402a24b5ca2a660e84f9d5"; sid:1;)
Add keyword to do "raw" matching on each of the certificates in the
TLS certificate sticky buffer.
Example:
alert tls any any -> any any (msg:"tls.certs test"; tls.certs; \
content:"|01 02 03 04|"; sid:1;)