Clean up base SNMP script. Mostly docs, some logic refactors.

This commit is contained in:
Jon Siwek 2014-05-02 12:09:06 -05:00
parent 2e84e1f78c
commit 3905b6fc70
3 changed files with 62 additions and 36 deletions

14
CHANGES
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@ -1,4 +1,18 @@
2.2-409 | 2014-05-02 12:09:06 -0500
* Clean up and documentation for base SNMP script. (Jon Siwek)
* Update base SNMP script to now produce a snmp.log. (Seth Hall)
* Add DH support to SSL analyzer. When using DHE or DH-Anon, sever
key parameters are now available in scriptland. Also add script to
alert on weak certificate keys or weak dh-params. (Bernhard Amann)
* Add a few more ciphers Bro did not know at all so far. (Bernhard Amann)
* Log chosen curve when using ec cipher suite in TLS. (Bernhard Amann)
2.2-397 | 2014-05-01 20:29:20 -0700
* Fix reference counting for lookup_ID() usages. (Jon Siwek)

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@ -1 +1 @@
2.2-397
2.2-409

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@ -1,45 +1,68 @@
##! Enables analysis of SNMP datagrams.
##! Enables analysis and logging of SNMP datagrams.
module SNMP;
export {
redef enum Log::ID += { LOG };
## Information tracked per SNMP session.
type Info: record {
## Timestamp of first packet belonging to the SNMP session.
ts: time &log;
## The unique ID for the connection.
uid: string &log;
## The connection's 5-tuple of addresses/ports (ports inherently
## include transport protocol information)
id: conn_id &log;
## The amount of time between the first packet beloning to
## the SNMP session and the latest one seen.
duration: interval &log &default=0secs;
## The version of SNMP being used.
version: string &log;
## The community string of the first SNMP packet associated with
## the session. This is used as part of SNMP's (v1 and v2c)
## administrative/security framework. See :rfc:`1157` or :rfc:`1901`.
community: string &log &optional;
## The number of variable bindings in GetRequest/GetNextRequest PDUs
## seen for the session.
get_requests: count &log &default=0;
## The number of variable bindings in GetBulkRequest PDUs seen for
## the session.
get_bulk_requests: count &log &default=0;
## The number of variable bindings in GetResponse/Response PDUs seen
## for the session.
get_responses: count &log &default=0;
## The number of variable bindings in SetRequest PDUs seen for
## the session.
set_requests: count &log &default=0;
## A system description of the SNMP responder endpoint.
display_string: string &log &optional;
## The time at which the SNMP responder endpoint claims it's been
## up since.
up_since: time &log &optional;
};
## Maps an SNMP version integer to a human readable string.
const version_map: table[count] of string = {
[0] = "1",
[1] = "2c",
[3] = "3",
} &redef &default="unknown";
## Event that can be handled to access the SNMP record as it is sent on
## to the logging framework.
global log_snmp: event(rec: Info);
}
redef record connection += {
snmp: SNMP::Info &optional;
};
global log_snmp: event(rec: Info);
}
const ports = { 161/udp, 162/udp };
redef likely_server_ports += { ports };
const version_map = {
[0] = "1",
[1] = "2c",
[3] = "3",
};
event bro_init() &priority=5
{
Analyzer::register_for_ports(Analyzer::ANALYZER_SNMP, ports);
@ -56,11 +79,12 @@ function init_state(c: connection, h: SNMP::Header): Info
}
local s = c$snmp;
if ( ! s?$community )
{
if ( h?$v1 )
s$community = h$v1$community;
if ( h?$v2 )
else if ( h?$v2 )
s$community = h$v2$community;
}
@ -78,39 +102,30 @@ event connection_state_remove(c: connection) &priority=-5
event snmp_get_request(c: connection, is_orig: bool, header: SNMP::Header, pdu: SNMP::PDU) &priority=5
{
local s = init_state(c, header);
for ( i in pdu$bindings )
{
++s$get_requests;
}
s$get_requests += |pdu$bindings|;
}
event snmp_get_bulk_request(c: connection, is_orig: bool, header: SNMP::Header, pdu: SNMP::BulkPDU) &priority=5
{
local s = init_state(c, header);
for ( i in pdu$bindings )
{
++s$get_bulk_requests;
}
s$get_bulk_requests += |pdu$bindings|;
}
event snmp_get_next_request(c: connection, is_orig: bool, header: SNMP::Header, pdu: SNMP::PDU) &priority=5
{
local s = init_state(c, header);
for ( i in pdu$bindings )
{
++s$get_requests;
}
s$get_requests += |pdu$bindings|;
}
event snmp_response(c: connection, is_orig: bool, header: SNMP::Header, pdu: SNMP::PDU) &priority=5
{
local s = init_state(c, header);
s$get_responses += |pdu$bindings|;
for ( i in pdu$bindings )
{
++s$get_responses;
local binding = pdu$bindings[i];
if ( binding$oid == "1.3.6.1.2.1.1.1.0" && binding$value?$octets )
c$snmp$display_string = binding$value$octets;
else if ( binding$oid == "1.3.6.1.2.1.1.3.0" && binding$value?$unsigned )
@ -124,10 +139,7 @@ event snmp_response(c: connection, is_orig: bool, header: SNMP::Header, pdu: SNM
event snmp_set_request(c: connection, is_orig: bool, header: SNMP::Header, pdu: SNMP::PDU) &priority=5
{
local s = init_state(c, header);
for ( i in pdu$bindings )
{
++s$set_requests;
}
s$set_requests += |pdu$bindings|;
}
event snmp_trap(c: connection, is_orig: bool, header: SNMP::Header, pdu: SNMP::TrapPDU) &priority=5
@ -165,6 +177,6 @@ event snmp_encrypted_pdu(c: connection, is_orig: bool, header: SNMP::Header) &pr
init_state(c, header);
}
event snmp_unknown_header_version(c: connection, is_orig: bool, version: count) &priority=5
{
}
#event snmp_unknown_header_version(c: connection, is_orig: bool, version: count) &priority=5
# {
# }